Ignition FAQ TCI & CDI Electronic Ignition / Stators & Charging Systems
This guide was started for the "YAMAHA VISION" motorcycle group (http://ridersofvision.net/). However, much of this info applies to any ignition / charging / electrical system. Specifically, how this stuff works, how to trace problems, and ultimately how the driveway mechanic might fix an electric, ignition -or- charging problem . If you have comments or corrections... PLEASE email. I will update this when I can. ©1999 Dave "Leather" Draper Jetav8r@JetAv8r.com . My Vision Info Site Here. "Yamaha Vision" Motorcycle Electronics / Ignition FAQ
Version 4.0 (July 2005) Designed for 1024x768 screens Photos & Diagrams
Main Links Download This Entire Guide As PDF How Does Electronic Ignition Work? (NEW page) The basics & big picture view of typical ignition systems Motorcycle Charging Systems and Vision Stator problems (NEW page) Basics of motorcycle charging How Vision TCI Works (jump on this same page) Electricity Guide (new page) Top Vision Links Yamaha Vision Riders Group
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (1 of 43)8/6/2005 7:13:08 AM Disassemble & Repair A Vision TCI (NEW page) Battery Guide (new page) Vision Resources Page Ignition FAQ Top Ignition Links Yamaha XZ550RJ/RK Ignition FAQ Table Of Contents
q q q q q q 1. Intro 2. Trouble shooting Overview r 2.1 Common sense approach r 2.2 What ARE the symptoms r 2.3 Quick Checklist r 2.4 Troubleshooting Chart 3. First Things to Check r 3.1 Fuses r 3.15 Replacing Fuse Box r 3.2 Connections r 3.25 Cleaning connectors r 3.3 Battery s 3.31 Battery Voltage test s 3.32 Battery Charging Circuit Test r 3.4 Moisture r 3.5 Spark Plugs! 4. Side Stand Relay r 4.1 Symptoms 4.2 How it works 4.3 Disconnecting 5. Engine Stop Switch 6. Rev Limiter + Tachometer r 6.1 Symptoms r 6.2 Disconnecting r 6.3 How Tach + Limiter work r 6.4 Inside the TACH q q q q 7. Electronic Ignition System Overview r 7.1 Symptoms r 7.2 What is TCI s 7.21 TCI is not CDI s 7.22 TCI vs. CDI s 7.23 How it works r 7.3 How Coil spark works r 7.4 How TCI works to fire coil r 7.5 Good news about TCI r 7.6 Bad News about TCI r 7.7 Replacement cost of TCI r 7.8 What's inside and goes bad r 7.9 How To Tell TCI Module bad 8. Pickup Sensors r 8.1 Tach Importance r 8.2 Symptoms r 8.3 Sensor ohm test s 8.31 Bad news about this test r 8.4 TCI pin to sensor check r 8.5 Pickup Crosstalk / Short s 8.51 Crosstalk check s 8.52 Short check r 8.6 Swap Pickup Test r 8.7 TCI manual triggering r 8.8 Replacing pickups 8.9 Pickup kills TCI 9. Checking TCI module (Power Checks) r 9.1 Pin / Plug Checks r 9.2 Voltage dropout test r 9.3 Test while running q q q q 11. "Wasted Spark" r 11.1 Common Coil Spark r 11.2 Vision Wasted Spark s 11.21 Symptom s 11.22 How It Works 12. TCI Power-On Tests r 12.1 Test at SparkPlug r 12.2 Test at TCI 13. COILS r 13.1 Symptoms r 13.2 Spark Test r 13.3 Ohm Test r 13.4 Swap coil test r 13.5 Plug Wire Check 14. Ignition Cares r 14.1 Ignition Burnout r 14.2 Coil Care === A P P E N D I X ====
q q q A1. TCI Pin/Plug Diagram A2. Spark Test A3. Multi meter Use r A3.1 Calibrate ohm Scale r A3.2 Volts vs Amps r A3.25How To Measure A Good 12 Volt Connection r A3.3 Testing Current Draw r A3.4 Voltage Drop r A3.5 "Near Ground" file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (2 of 43)8/6/2005 7:13:08 AM Ignition FAQ
q 10. TCI Disassembling + Inspection r 10.1 Why? (=Moisture problem!) r 10.2 Getting Inside "The Black Box" r 10.3 What You Will See r 10.4 Moisture Solution q q q q q q q A4. Battery Theory and Care A5. Removing TCI Wires From Plugs (to be added) A6. Electrical Theory / Formulas A7. Rebuilding A TCI module B1. The Author B2. Credits & Contributors B3. Revisions & Corrections top 1.0=> INTRO The document you're reading here (and below) is primarily about the Vision Electronics with emphasis on solving ignition problems. If you want to read about how most all ignitions work then open the new page on ignition basics listed above. If you want to understand basic motorcycle charging systems or have problems specifically with the Vision open the new charging page listed above. If you're already convinced your Vision TCI is bad and are motivated enough to try a fix it, open the new page above on fixing a TCI. We have not had anyone document in detail fixing a TCI but clearly know that it has been done. Would be great to hear from someone who has done it. There are also 2 other pages dealing with basic electronic theory and batteries. The `82/`83 VISION has a "Transistor Controlled Ignition" system ("TCI"). This type of ignition is used on many older non-automotive motors (look at a Virago...) and is closely related to modern Capacitive Discharge Ignition ("CDI") systems. While technology advances bring us to the computerized ignition systems of today, the principles of ignition have remained fairly the same. The 2-cyclinder Vision motorcycle TCI system consists of :
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (3 of 43)8/6/2005 7:13:08 AM Ignition FAQ - 2 sensor pickups under the crankshaft cover - magnet on outside edge of flywheel (triggers sensor pickups) - 2 spark coils (1 for each cyclinder) - a solid state module box ("ignitor") that controls the spark Solid state (electronic) ignitions were introduced in the early 70's (my '72 Outboard has one), became widely used in autos in the mid 80's and are now common on ALL motors. The Vision ignition has the typical problems associated with older (and poorly built) solid state ignition systems. The sensors or control module will fail completely ... -OR- ... (more frustratingly) the ignition becomes erratic and usually increasingly worse when hot. Electronic Ignitions fail usually due to: - electronic components (switching transistors) in the system breaking down with heat (older transistors were not as good as today) - material defects (bad or broken solder joints) - corrosion and bad connections to the module or inside the module - normal life span ("MTF" mean time between failure rate) of older electronics (diodes, transistors, etc) Lets face it, electronics don't last forever and I'll bet you don't have your first stereo anymore either (or do you ?!?!! you cheapskate). A Vision TCI cost about $400 new and about $50 used. If you have ignition problems you know your ride is not worth too much more than that. Still... it's a great ride!! If you want to fix it affordably here's your best chance. Eliminate ignition problems in an organized progression and you will minimize the chance of buying a expensive parts you really didn't need. (..... example: "put the coil back, you really don't need a new coil" ......) top 2.0 => TROUBLE SHOOTING OVERVIEW
top2.1 [COMMON SENSE APPROACH] You want to narrow down ALL the possibilities before you replace a TCI, PICKUP, or COIL. If you can get (beg, borrow, steal ..) a good spare ignition then DO IT. Bottom Line... You have 2 coils and 2 pickups. So you can eventually tell if one is BAD by using the other in its place. BUT there is no "SURE" test of the TCI. You can prove it's bad, but you can't prove it's good. Eliminate every other possibility and then you know it's a TCI module.
q REMEMBER Some Comon Sense Stuff r Plugs really do foul bad enough not to work (check spark with plug removed) r Don't confuse ignition symptoms for carb problems (again, check for spark) r Bad connections (voltage dropout) and fuses can produce all the same symptoms of bad TCI/Pickups r Dude ..... Is Your Battery Good ???? file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (4 of 43)8/6/2005 7:13:08 AM Ignition FAQ top2.2 [WHAT **ARE** THE SYMPTOMS] Exactly "WHAT IS GOING ON" ?? Take your time and write it down. Try to pin down your symptoms: -Is just ONE cylinder misfiring? Which one? It makes a difference! -What is the Tach doing during the problem since the TCI drives the tach too -What conditions make it happen/worse?..after getting hot / been running awhile / bumps / etc.. top2.3 [Quick Check List In Priority Order] [ [ [ [ [ [ [ [ ] ] ] ] ] ] ] ] a. Fuses b. Connections c. Voltage Dropouts d. Battery e. Spark Plugs and Wires f. Side Stand Relay g. Engine Stop Switch h. Rev Limiter Wire [ [ [ [ [ ] ] ] ] ] i. TCI Power On Test j. TCI module Power/Voltage Checks k. TCI disassembly + inspection l. Sensor Ohm Check / Swap Test m. Coils Ohm Check / Swap Test top 2.4 ["The Matrix"] Symptoms Possible Problem / Solution
Sparkplug fouled or Plug Wire bad Rev Limiter -> cut Yellow/Black wire at TCI 6-prong plug Front Pickup -> check / swap Front coil -> check / swap TCI -> check / swap Front Cyl ONLY misfire / Inop file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (5 of 43)8/6/2005 7:13:08 AM Ignition FAQ Rear Cyl ONLY misfire / Inop Tach Works fine Sparkplug fouled or Plug Wire bad Rear Coil -> check / swap Grey wire Bad From TCI to coil {TCI is triggering tach correctly, sensor good} Rear Pickup -> check / swap TCI -> check / swap Side Stand Relay -> Cut Black/White wire at TCI 6-prong plug TCI-> Check/Swap (Try Power On test). Rear Cyl ONLY misfire/Inop Tach Jumps around wildly or inop BOTH cyl die together, bike won't run Tach dies also (goes zero) BOTH cyl die together And starter won't work Both cylinders misfire Engine runs real erratic May run fine high RPM but not low (or visa-versa) May not start or spark at all Worse when hot Run switch bad -> Try Separate 12v wire and test Most likely TCI problem or bad connection to TCI Check connections and voltages TCI -> power on tests TCI -> Inspection Ignition good till under load Bad Battery Connections - Voltage drop somewhere Bad Connections TCI -> Open Inspect for obvious flaws / moisture Ignition good some days not others top 3.0 => [OBVIOUS THINGS TO CHECK]
top3.1 FUSE BOX The fuse box under the seat should be replaced. Especially the 10amp ignition fuse! It provides +12v power to the ignition module / coils / safety relays. A poor connection here can result in ALL of the ignition symptoms!! file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (6 of 43)8/6/2005 7:13:08 AM Ignition FAQ top3.15 REPLACING FUSE BOX Replace each fuse with plastic "ATC BLADE" type fuses. Get the good ones with a rubber case and snap on tops. Look in a good marine store ("Boats US") or auto shop ("Pep Boys", etc...). Solder these inline into the wiring harness. Use shrink tubing / electrical tape / liquid rubber / or "Die-electric grease to insulate the connections from ground. The idea here is to prevent ANY corrosion from getting in these connections. IT CAN MAKE A REALLY BIG DIFFERENCE! top3.16 PROTECTING CONNECTIONS A GOOD technique is to use "Dielectic" grease to protect fuses and connectors. This is SPECIAL grease that WON'T conduct electricity. Get in good auto parts store. GET THE RIGHT STUFF or you'll have big problems on your hands. Dab the stuff all over connections AFTER THEY ARE CONNECTED (not before) you want to protect. top3.2 CONNECTIONS and HOW TO REALLY CHECK FOR A GOOD 12 VOLTS Most of the wire connections (especially in the plastic plugs) are "crimped on" connectors. These are especially prone to corrosion or getting "loose". A "BAD" connection is easier to find than a "POOR" connection. Here's why. A "poor" connection will conduct +12 volts (shows good on your multimeter) but may cause enough "voltage drop" that there's really no power (amps) going to the thing its supposed to (TCI / COIL / PICKUPS). A poor ground or is EQUALLY BAD! -or- The connector will conduct 12volts ... but only enough to drive the mulitmeter... not the part you really to make sure is working! If you're not sure what this means.... please read the section on Multimeter use / amp vs volts / testing good connections (Multi meter Use.) My favorite technique when checking a circuit I'm not %100 sure of is to "plug" something into it to see if it works. A good 12v lamp (small headlight) is good for this. If the connection (or gound) will drive the light.... you know it can handle the load of whatever your concerned about. Now you can check for these bad connections (read the the appendix section on multimeter use) BUT to my way of thinking just make all your connections "bulletproof" (replace if needed) in the ignition system and then you don't have to worry. The telltail symptom of a bad connection is hot wires and/or melted plastic connectors. NOTE : Look at the white plastic connector on left side of bike that connects the Rectifier to the Stator wires. This is a VERY common place to see the "melted connector" effect of a corroded connector. AND.... if this connector is bad the bike is NOT getting the electricity it needs. Most riders recommend you cut and permanently solder this connection to be absolutely sure. file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (7 of 43)8/6/2005 7:13:08 AM Ignition FAQ top3.25 CLEANING CONNECTIONS To CLEAN the plug connectors pull them apart, clean them with a small file or knife. Some people like pencil erasers. Emery boards or 400 - 600 grade sandpaper are OK but remember to clean out the grit (... or you could make it worse). Apply WD-40 (or CRC) liberally to wash the gunk out. Reseat all the plugs. There are not that many. Specifically, remove right engine cover. Pull off the 2 plugs into the TCI "IGNITOR" module. Behind the cover the TCI is mounted is the "side stand relay". Reseat those plugs too. top3.3 BATTERY A subtle problem with motorcycles is it doesn't take much power to "crank" one. So, that's not always a good measure of the battery status. In fact, by the time your battery gets to sounding "low" on the starter its just about gone. AND if it "low" while running it could cause these symptoms: tach jump / tach dropout / random misfire both cylinders. top3.31 CHECKING BATTERY Using VOLTMETER Pull the 6-prong plug off the TCI (you want no ignition for this). Connect the voltmeter to the battery and crank the engine. While cranking you should NOT see less than 9-10 volts. With the bike running at about idle (2000rpm) you should see about 13-14 volts. top3.32 CHECKING BATTERY CHARGING Using AMP METER INLINE This is more involved. But ... if you are motivated. As you suspect there is a good relationship between your battery and charging circuit ("STATORS"). The stators in the VISION are notorious. So this may be worth doing. You need a multi meter with a good Ammeter scale capable of 10amps or better. You are going to check the battery charging system while the bike is running. 1- Disconnect the RED cable from the +12 Positive terminal on the battery. 2- Hook the Ammeter between the battery and RED cable. Hook the RED test lead to the RED cable end and BLACK tester lead to the battery terminal. You are completing the circuit from the bike to the battery. CAUTION: file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (8 of 43)8/6/2005 7:13:08 AM Ignition FAQ MAKE SURE THE MULTIMETER IS IN THE 10 AMP MODE !!! NEVER : DO NOT Run The Bike with the battery completely disconnected from the engine
3- Since you can't start the bike this way (that draws way more than 10 AMPS) you need to make another temporary connection alongside your multimeter (in parallel). Use a jumper cable 4. Start the bike. Then disconnect the jumper cable (the multimeter is still connected between the RED cable end and battery.... so the bike should keep running) 5. The ammeter is now showing the "draw" or "Charge" taking place to the battery. 6. Assuming your battery needs charging (almost always!) the needle should show a positive deflection at around ???? amps at idle and a little more as you rev up the bike. 7. Stop the motor. With it not running but IGNITION ON, look at the amp draw. Ignition and accessories should slightly peg the meter on the left side of case. If you want to see the exact draw swap the RED and BLACK TEST LEADS around. Amp draw without the motor running for stock VISION is about ???? with headlight in low beam. *** NOTE: Read the Appendix section on Battery Care top3.4 MOISTURE Moisture inside the TCI module will produce ALL the ignition symptoms. This is addressed later BUT be aware the TCI is NOT a sealed unit like most ignition modules. WD-40 stands for "Water Displacement" on the 40th try (long story). The bottom line: spray a bunch on your TCI circuit board can't hurt. top3.5 SPARK PLUGS Plugs rarely go bad BUT that doesn't mean you can rule it out. Because the VISION uses TCI instead of "CDI" (read section on difference) the plugs are more susceptible to fouling. You can foul a plug bad enough IT WILL NOT WORK! I fouled one this bad while experimenting for this guide. A good spark at the wire end (screw or nail inserted) doesn't show you what the plug is really doing. Pull out the plugs, clean, and check for good spark with the plugs out and the case grounded. Look for a nice sharp blue colored spark that you can noticeably
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (9 of 43)8/6/2005 7:13:08 AM Ignition FAQ "hear". Try NOT to run your bike without the plug wires attached to something to spark to. Otherwise, you may encourage a spark out the side of the coil where insulation may be old and poor. top 4.0=>SIDE STAND RELAY
top4.1[SYMPTOMS] The side stand relay must be powered or the ignition unit is "killed". So, if the Side Stand relay or circuit is faulty it will cause the engine to cutout altogether (maybe intermittently). The key here is "ALTOGETHER". Another words BOTH cylinders together. If the engine runs on ONE cylinder (ever) then THIS IS NOT YOUR PROBLEM. A faulty side-stand relay/circuit kills the WHOLE ignition. The tach WILL GO TO ZERO! Now if the engine is running intermittently so rough you can't tell if its one -or- both cylinders then this is worth checking! top4.2[HOW IT WORKS] The VISION has a safety lock to prevent you from running the engine with the side stand down (and the bike NOT in neutral). In the VISION the ignition is "Killed" (tach goes to zero) when the BLACK/WHITE wire coming from the TCI module (6-prong plug) is connected to the frame = GROUND = -12volts. This is done by the "Side-Stand Relay". Normally, when the side stand is up the relay is energized with +12 power and held "OPEN" to disconnect the TCI module B/W wire from ground. When the side stand is down, the relay loses power and closes, connecting the B/W wire to ground. So, if the relay is not "powered" (bad connections) or is shorting out ...it can intermittently kill the ignition and tach. top4.3[DISCONNECTING / CHECKING SIDE STAND RELAY] Find the BLACK / WHITE striped wire coming out of the 6-prong plug in the side of the TCI ignitor module case. Either remove the wire-pin socket from the plug (harder to do) or just cut the wire and tape the ends. With the BLACK/WHITE striped the wire cut, the ignition can't be connected to ground and will work fine. If this is the problem.... Fix/replace the relay or connections to the relay. If you leave the BLACK/WHITE wire disconnected... just remember your bike will run with the side stand down. Use your judgment, as this IS a safety device. The side-stand relay is under the right engine cover, behind the plastic cover which the small square "TCI" ignition module is mounted to. That plastic cover also holds the water reservoir. top
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (10 of 43)8/6/2005 7:13:08 AM Ignition FAQ #5=> ENGINE RUN/STOP SWITCH
The run/stop switch on the handlebars provides +12 volts to the ignition, coils, starter cutout relay, and the side-stand relay. So it's unlikely this is the problem if you can get your bike to "crank" and start. BUT AGAIN, if your bike is cutting out (totally ,both cylinders, tach goes to zero) intermittently after you get it running... this could be the problem. top #6=> REV LIMITER CIRCUIT top6.1 [SYMPTOMS] YES ITS TRUE!. The VISION has a "REV-LIMITER" circuit that kills the FRONT coil ignition if the TACH reads over 12,000rpm. The TACH reads the fire pulse from the TCI to the REAR coil (via the GREY wire from the TCI to the rear coil). That GREY wire splits somewhere under the gas tank. If the tach senses an over-rev it GROUNDS the Yellow/Black wire to the TCI. The TCI kills the front cyclinder coil pulse. If the circuit malfunctions you'll most likely lose the FRONT CYLINDER ONLY (the tach falsely tells the TCI its overrevved). But, it could also kill the REAR too if the tach shorts out altogether and also shorts the Gray REAR coil trigger wire. You will not affect ANY part of the ignition /charging system by disconnecting the Yellow/Black wire from the TCI. Why would you want to keep the Rev Limiter? My best answer would be incase you drop the bike, its laying on its side running with the throttle somehow pinned opn. top6.2 [DISCONNECTING REV LIMITER] *** CUT YELLOW/BLACK stripped WIRE in 6-prong plug at TCI *** (Tape the ends) top6.3 [HOW TACH & REV LIMIT WORK] The Tach has 4 wires connected to it: [BROWN] = +12 volt Power
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (11 of 43)8/6/2005 7:13:08 AM Ignition FAQ [BLACK] = -12 volts Ground [GRAY] = Ignition pulse signal that the tach reads. It is a "tap" off the Gray wire from the TCI to the REAR cylinder coil. That splice is under the gas tank. ** That's why if you lose the rear cylinder ignition you lose the TACH. **
The GRAY wire signal from the TCI is a "square wave" trigger to the Coils primary winding. It is normally "near" ground and the trigger is +12v to fire the coil and pulse the tach. To be exact: in the Tach I dismantled the GRAY wire became ORANGE after the 3-prong connector block outside the instrument cluster (contrary to every wiring diagram I have). [YELLOW/BLACK stripped wire] = This is the Rev-Limit connection. This is a single wire between the Tach and TCI. When the "Rev-Limiter" switches ON IN THE TACH it grounds the YELLOW/BLACK wire. You can try this yourself. At the TCI disconnect the YELLOW/BLACK wire in the 6-prong plug in the side of the TCI. Then while the bike is running, ground the pin where the YELLOW/BLACK wire would be connected. It causes the same thing: The "Rev-Limiter" KILLS THE IGNITION to the FRONT CYLINDER coil at about 12,000rpm. If you're curious how I know this... I connected an "oscillator" to the Tach, powered it up and ran the tach up to... well, pegged. It thinks it's connected to the engine. At 12,000 exact (on my bike) it grounds the Y/B wire. top6.4 [INSIDE THE TACH] file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (12 of 43)8/6/2005 7:13:08 AM Ignition FAQ Inside the Tach are 2 small separate circuit boards. One is the Tach. And the other is obviously this "Rev-Limit" switch. I say "switch", but this is a "solidstate" circuit board switch (NOT a mechanical one). An IC chip on this board is obviously counting RPM. top #7=> IGNITION SYSTEM OVERVIEW ".....plugging in a spare TCI is worth a thousand words....." - Author Known
top7.1 [SYMPTOMS]
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (13 of 43)8/6/2005 7:13:08 AM Ignition FAQ There's are a million of them... but these appear most common: - While riding one cylinder will stop firing intermittently at higher rpm. The bike still runs on one cylinder but with a lot less power and will be very hard to start if you stall it. The tach MAY go to zero when this happens. Typically this lasts about 2 - 15 seconds and then may cut back in and run normally. - Both cylinders will alternately stop firing. Sometimes it will not run at all at low rpm. Tach is also at zero or may jump around wildly. Bike backfires badly, etc... Gets worse when its hot. top7.2 [WHAT IS "TCI"] Ignition systems have evolved over the years and been called many things: Solid State, Ignitors, Breakerless ,Pointless, Distributorless, etc... In outboards they're called "Powerpacks" or "Pulse packs". They go bad about every 5-10 years and also cost a boatload (excuse the pun). Yamaha calls this a "TCI" (Transistor Controlled Ignition) or "Ignitor" pack. In autos we call them "CDI" (Capacitive Discharge Ignition), ECU (Electronic ControlUnit), or DIS (Distributorless Ignition System). I will say TCI and CDI for simplicity but ..... top7.21 ["TCI" IS NOT "CDI"] I Repeat ..."TCI" is Not "CDI" The differences are subtle BUT you need to understand them or BAD things can happen To be exact TCI uses transistor switches to disconnect the coils. This causes a charged coil to collapse and "fire" the spark. This is known as "Kettering" or "Induction" effect. So, in the VISION the coils are powered up all the time except while "collapsing" into spark. The VISION coils are constantly powered up at 12+ volts but the "induction" energy stored in the coils secondary core is about 20,000volts TCI is an "INDUCTION" ignition system
CDI systems use a different technique. While the pickup and triggering is the same, the output from a CDI ignition module is a short high voltage pulse to the coil. In a CDI system the coil doesn't store the spark but instead AMPLIFIES the pulse from the CDI unit to a much higher level. The pulse is from the CDI module is normally about 250-500volts. The CDI coil acts like a transformer and steps the voltage even higher. A CDI coil typically steps up the voltage 100:1. Do the math and you see a modern CDI coil is outputing 25,000-50,000volts (Oh-Baby).The spark coils here are wired directly to ground and are waiting for the high voltage pulse from the CDI module. "CDI CAN KILL" :That's why there are warning stickers all over your auto engine bay. The CDI module itself can give you a
WICKED shock (not just the coil) and ...the coil output can KILL YOU. CDI is a "CAPACITIVE DISCHARGE" system
.
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (14 of 43)8/6/2005 7:13:08 AM Ignition FAQ top7.22 [CDI vs. TCI] The higher output voltage of a CDI module produces a much higher cooresponding coil output voltage . So, CDI produces a much hotter cleaner spark. It is the ignition of choice among race teams and now widely used for everything. The "CD" in CDI means capacitive discharge. This refers to the high voltage output of the CDI module which comes from a "mini" coil circuit of its own. The downside to CDI is the short high voltage spark pulse duration. This is better at high RPM but makes starting difficult. You will notice many CDI ignition systems that use a starting "ballast resistor" type circuit. This circuit ups the spark output in the CDI ignition for starting only. TCI produces a longer spark duration (which some might argue is more reliable). top7.23 [How CDI / TCI works] Click On Photo For Click On Photo For BIGGER Pickup Magnet on Flywheel Outside BIGGER (2) Ignition Pickups (on right of stator) A CDI module picks up a signal sent from a sensor usually otside the flywheel. The sensor can be optical (infared) but most often is electro-magnetic. In smaller or older engines (like motorcycles) the system is usually a magnetic rotor and coil pickup. The other "Hall effect systems" are usually used in auto or newer motors. Hall effect pickups are different and need to be powered, so there is usually 3 wires to those pickups. In the common motorcycle pickup a magnet on the flywheel passes by a small coil pickup. This produces a small electric pulse in the coil just like it does in your larger magnet-stator charging circuit. This small pulse is amplified inside the ignition module and used to switch a transistor which in turn controls the coil. The flywheel usually has a combination of magnets and pickups. In the Vision, there is one magnet and 2 pickups (one for each cyclinder). Since there is no distributor directing which cyclinder gets the spark each cyclinder has its own coil. Or, 2 opposing (180degrees out) cyclinders can share the same coil and get
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (15 of 43)8/6/2005 7:13:08 AM Ignition FAQ twice as many sparks (1 in compression and one wasted in exhaust stroke (Refer to "wasted spark" section). The gap distance between the magnet and sensor is very important as is the "phase" (when the magnet passes the sensor). The magnet is producing a "sine-wave" (low-high-low voltage) pulse for the CDI .The low to high pulse is the trigger. The peak voltage produced by most sensors is around 5volts. In the VISION the 2 sensor pickups are under the left crankcase cover at the crankshaft flywheel end. The magnet is built into the outside surface of theVision flywheel. top7.3 [HOW COIL SPARK WORKS ... EXACTLY] The spark plug COIL is exactly that: 2 LONG lengths of thin wire wound side-by-side tightly around a cylinder spool (a "coil" of wire). The first PRIMARY WINDING length of wire is proportionally shorter than the SECONDARY WINDING. As example, the coil may have 100,000 wraps of wire around it but the second winding is 200 times longer ( wrapped 200:1 ....whatever). Since the wires are so thin and close, the second wire picks up the same electrical voltage (charge) flowing through the first. If the wires were the same length, connecting +12volts to the primary wire (other end to -12 ground) would charge the second wire up to 12v also. But, in a spark coil the secondary wire charges up to a voltage proportionally higher than the first since the secondary wire is so much longer (literally more wire to "fill" with electricity). Remember, the PRIMARY and SECONDARY wires are NOT connected. But they are just so close to each other that they pick up proportional charges. In layman's terms: when one end of the primary wire is cutoff, the charge still left in the primary wire flows back to the battery. But the longer secondary wire (charged now to HIGH VOLTAGE) is NOT connected back to the battery and its high voltage charge has got to go somewhere! It gets back to "ground" (the battery) by "jumping" the short gap in the spark plug (or YOU if you happen to be holding the plug wire). In the VISION the spark plug coil has a constant +12 volts flowing into the "PRIMARY WINDING". This causes the longer "SECONDARY WINDING" wire in the coil to charge up to a high voltage. When the +12 volts of the PRIMARY WINDING is briefly interrupted by the TCI, the coil electrically "Collapses" and causes the high voltage SECONDARY winding to discharge (the Spark). The input to the coil is +12 volts, but the high voltage output spark is over 10,000 volts. Again, the difference between "Induction" (TCI) and CDI systems is this: file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (16 of 43)8/6/2005 7:13:08 AM Ignition FAQ TCI collapses an already charged coil by disconnecting it (TCI switches off briefly). These systems generally use a higher resistance type coil and are known as an "induction" or "Kettering" ignition systems. CDI sends a brief high (200+) voltage pulse to an uncharged coil which act like a transformer and multiplies it even higher. The step up is normally around 100:1. These systems tend to use low resistance or "racing" oils. CDI modules normally use low resistance type coils. Remember that CDI is "shooting" a voltage pulse through the coil. TCI (or induction ignitions) use (and expect) higher resistance "induction" type coils. Remember current is flowing through the TCI to the induction coils continuously and the coil is fired when the TCI shuts it off. The importance of this is: Do Not Use a "racing" -or- low resistance type coil in an "induction" ignition (or TCI) system. The low resistance coil will flow more current thru the TCI and produce the legendary "Hot Toaster" effect. Though it will work for awhile, you will eventually burn the TCI module out. In CDI this whole process of charge/discharge is near instantaneous. An 8-cylinder car running 5,000rpm is firing the single coil about 333 times a second. The output voltage of the coil depends on the input voltage and how much longer the secondary winding is. Some modern car ignition coils output well over 40,000 volts. This can KILL! The VISION TCI coil is probably (guessing here) about 20,000volts and if you get sparked will just shock the heck out of you. top7.35 ["DWELL" -or- "DWELL ANGLE"] Dwell time used to refer mostly to the mechanical time the distributor points are closed in old ignition systems. This affected the charge time of the coil and spark length. Dwell was important then because at higher RPM the dwell time was not enough to fully charge the induction coil. That meant less voltage spark at higher RPM (...BAD). There was also the problem of how fast a point could open and close without "floating" (a problem you have with valves also). There was a real balance between dwell time at high RPM, how much voltage you needed for high RPM spark, how much voltage you could actually push thru a point without burning it up, and then what would happen at low rpm (long dwell times) when all that voltage was just heating up the coils. In newer CDI systems this term is near meaningless for several reasons. Solid state devices (like transistors)control the discharge pulses electronically with near instantaneous timings. So the dwell times can be finely controlled to achieve the best coil / spark outputs for a given RPM. Transistors can handle a LARGE amounts of voltage/current (compared to points). And, newer generation coils are extremely (microseconds) fast so charge / discharge times are not a huge factor (unless racing). Newer racing ignitions (like MSD) are NOT producing bigger sparks with long durations but in fact getting more effecient burn by producing very controlled multiple short duration sparks to the plug. top7.4 [HOW the TCI Fires The COIL Exactly] The flywheel pickup signal is fed to the TCI module. Inside is a "TIMING" chip which controls the length of the spark and also its timing relative to the RPM. As RPM increase the timing is advanced. In the VISION this is 10 degrees ("top dead center") at 1,300rpm to 38 degrees TDC at 4,000rpm. Remember, in old engines the ignition timing was "advanced" with RPM by using a vacuum driven diaphragm or a centrifugal weight on the rotor. With CDI it is electronically advanced in the ignition "timing" chip based on some mathematical graph the manufacture has developed to maximize the engine horsepower in that RPM range (that was too a long sentence). If you have the VISION service manual you can see the timing graph on page 8-14.
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (17 of 43)8/6/2005 7:13:08 AM Ignition FAQ The TCI module uses a "switching" transistor to "fire" the coil. This is how: - The coil gets a +12 volt input direct FROM the battery (via ignition sw). It is grounded (the circuit completed) BY the TCI. The TCI transistor switches "OFF" the coil ground to collapse the coil and cause the secondary coil winding to spark. If you test the Gray (or Orange) wire FROM (that's right... from!) the coil you'll see +12 volts. If you look at the TCI pin you'll see near ground until the fire signal. Then the TCI actually pulses a +12 volts at the pin. This is a "forceful" way of "cutting"off the PRIMARY wire ground and forcing the SECONDARY winding spark. The VISION has 2 coils (one for each cylinder). So, the TCI module has 1 timing chip and 2 transistors. One for each coil. The VISION's 2 coils are mounted REALLY INCONVIENETLY under the gas tank inside the frame. To get to them you need to remove the gas tank. But coils VERY RARELY go bad! And when they do they usually stop working period (not intermittently). The odds are REALLY small they both stopped working intermittently. top7.5 [WHAT"S GOOD ABOUT CDI] There are no moving parts like relays/points/rotors to wear out or adjust. In theory, a CDI engine never needs an ignition tune-up again (you know, timing light, etc...) This is not always true. Remember, a car engine has 1 coil. They use a turning rotor under the distributor cap which determines which spark plug gets the spark. This does gets worn a bit since it involves a timing belt to drive the rotor and the rotor itself wears. In the VISION there are NO moving parts because each cylinder has its own spark coil and there is no rotor. In newer high tech engines you will see CDI ignitions with seperate coils mounted atop the spark plug for each cyclinder. This eliminates the distributor slop and radio interference problems associated with long plug wires. top7.6 [WHAT GOES BAD IN CDIs] file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (18 of 43)8/6/2005 7:13:08 AM Ignition FAQ > Electronic components HATE heat!! That is why most CDI modules have lots of heat sink fins on them (Ever look how your Pentium chip is mounted?). DON'T leave your computer on all night!? But ...Yea-aah, don't turn it OFF and ON 5 times every hour either....?!? ...... because ....... > Integrated circuits also hate POWER SURGES! .........and the THERMAL stress of going from cold to hot to cold. The symptoms of ANY CDI type module going bad are very similar. They start to fail when the engine (and it) gets hot. They don't always fail altogether but gradually and intermittently as some or many IC components on the circuit board break down with heat. This is why a good electronic repair shop has cans of a "Freon" type spray (turn your "AIR DUST OFF" spray can upside down.... its the same thing). They will selectively chill each component till they can find the one that's breaking down with heat. I'll bet many CDI modules that quit after start will work OK if you chill them down. top7.7 [THE HARSH TRUTH ABOUT BROKEN TCI / CDI MODULES] You Cannot Prove A TCI / CDI is Good. You can only prove that its BAD.
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (19 of 43)8/6/2005 7:13:08 AM Ignition FAQ With the exception of newer automobiles and high end fuel injected marine motors .... manufacturers make NO "test bed"module you can plug a CDI into which will test if it's good. Worse, most retail parts shops will sell you electronic parts as is and you own them when you walk out the door (whether it turns out later you need them or not). A repair shop has the luxury of having some spares laying around. So they plug one in and see if it works. You can't aford this trial-and-error method because .... Older CDI modules are pricey ("they" got you and "they" know it). Not just Yamaha or because you have a VISION. Don't take it personally. Most CDI modules cost around $300-400. The Yamaha "TCI" ignitor module costs $500 retail as of 2001 (at least you can get one). To soften the blow($) and REALLY to be safer outboard makers are now using separate CDI modules and coils for each cylinder. So when one goes bad it doesn't kill the whole engine and each CDI only costs about $80. And many bikes now use several of them for the same reason. If you do the math, you realize it may not be worth repairing. My wife always seems to be able to do THIS math !??. THANK GOD FOR EBAY !? top7.8 [WHAT'S INSIDE A CDI MODULE] Most CDI units are encased in Epoxy resin or Epoxy-Rubber resin so you can't take them apart (Epoxy-Rubber resin will dissolves in acetone if you really want to see one apart) . They do this so moisture won't get in. The downside is heat buildup. WHAT YOU'D MOST LIKELY SEE is some resistors, capacitors, a couple transistors (you know, the ones that fire your spark plug coils). You'll also see the "timing chip". ANYWAY.... there's probably $10 in electronic parts and a $20 Ignition chip in a CDI module (I'm feeling generous). That a 1,200% markup!!. I'm in the wrong business. What goes bad in these things? Typically it is the "Timing" (Ignition) chip or the Transistors. The transistors really take a beating. That's what generates heat in the CDI since they're essentially a switch going on and off at 10,000rpm ???. Put your hand on the side of your big wattage stereo amplifier: HOT, same thing! That's where the heat sinks for the transistors are. And, the Ignition "Timing" chip is like any other IC chip. It's prone to breakdown with heat.
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (20 of 43)8/6/2005 7:13:08 AM Ignition FAQ top7.9 [CHECKING THE TCI MODULE] After reading all this, you'll be angry now when I tell you there's NO definitive test to check the TCI! You can prove the TCI is bad, but not that it is good. I recommend this order: #1. The TCI "power-on test" (section 12) will show you right away if the TCI system is NOT working. Go There Now -> TCI Power-On Tests #2. Check the Sensors (section 8). This is most likely if you have one cylinder missing (not both). Next Section #3. Check TCI voltages (section 9). Go There Now -> TCI Connector Checks #4. Disassemble TCI for inspection (section 10). Go There Now -> TCI Inspection #5. Rebuild the TCI module. Go There Now -> TCI Rebuild top #8=> PICKUP SENSORS file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (21 of 43)8/6/2005 7:13:08 AM Ignition FAQ Click for big Click for big photo Pickup Magnet on Flywheel Outside photo (2) Ignition Pickups (on right of stator) top8.1 [TACH symptoms] Remember the TACH is DRIVEN BY the TCI via the REAR pickup sensor. If TACH is good, rear sensor is good. top8.2 [BAD SENSOR SYMPTOMS] If only ONE cylinder is misfiring then suspect all these: the PICKUP / COIL / TCI. Check all 3! It would seem unlikely for BOTH (one for each cylinder) pickups to go bad together at the same time. That would result in both cylinders misfiring. BUT - pickup sensor "crosstalk" -or- shorting is possible. That WOULD give those symptoms. top8.3 [CHECKING PICKUP ohm RESISTANCE] The VISION has 2 sensor pickups mounted on a single plate assembly. Each sensor pickup is a small "coil". You can check for "continuity" (no break in the internal coil wire) and also the correct resistance you'd expect of a coil that is not shorted out (or corroded). file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (22 of 43)8/6/2005 7:13:08 AM Ignition FAQ Unplug the 4-prong plug from the TCI. At the plug the wires ends are : BLACK = GROUND (connected internally in TCI to the Black ground wire in 6-prong plug). This is the ground side of sensors. Both sensor grounds are tied together (one wire). WHITE = Rear cyl Pickup. RED = Front Cyl Pickup. Set Ohm Meter to Rx10 scale. Put Black lead clip on the BLACK wire pin socket of the plug (use a thin wire or safety needle to get in there). Put the RED test lead on the RED wire socket. Then the WHITE wire socket. AGAIN, the RED+BLACK wires are Front cyl sensor, the WHITE+BLACK wires are the Rear cly sensor. Sensor Pickup should read: 110 ohms (99-121 ohms is acceptable) in both cases. top8.31 [BAD NEWS ABOUT PICKUP ohm TEST] The continuity/OHM test ONLY checks the basic properties of the pickup coil. It doesn't really tell you FOR SURE if its working. I had an outboard with single pickup that tested perfect years ago. Spent lots of money to replace the CDI and single coil because the engine would die after getting hot. But ultimately, it was a new pickup that solved the problem It had ALL THE SAME SYMPTOMS OF A BAD CDI module?! top8.4 [CHECK TCI PINS TO SENSOR] Disconnect 4-Prong plug from TCI and check the male (protruding pins) on the module case. Connect the black test lead to the frame (ground), Ignition ON, and look for: Black wire pin = Ground.
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (23 of 43)8/6/2005 7:13:08 AM Ignition FAQ {Connected inside TCI to BLACK ground wire from 6-prong plug} Red wire pin = +1/2v (0.5v) White wire pin = +1/2v (0.5v) Put RED test lead on black wire and look for 0.5 volts when : RED wire plugged onto pin (White wire disconnected). WHITE wire plugged onto pin (RED wire disconnected). If you have good power at the TCI pin but not after going through the pickup something weird is going on. Suspect a short in pickup or wiring (possibly where it goes into crankcase, etc...). You would have seen a break in the wire with the ohm test. top8.5 [PICKUP CROSSTALK / SHORT symptoms] Since the pickups share a common ground "crosstalk" or a short between the two sensors is a real possibility. "Crosstalk" would result in one sensor triggering the wrong coil. A short between the sensors could cause unpredictable symptoms top8.51 [CROSSTALK CHECK] This is unknown. Without the schematic we're not sure how this works. Sorry dudes. top8.52 [PICKUP SHORT CHECK] You are looking to make sure there is no stray ground in the wiring. Put BLACK test lead on ground. Pull RED/WHITE/BLACK wires off (whole 4-prong plug) from TCI. Put RED test lead each wire end. You should not see GROUND. If you do suspect a short in the wiring somewhere to the frame or engine. PROBLEM IS this may be happening with the vibration of the engine. This would be very hard to see. Because of the shared ground you can't run the bike even on one cylinder and check this. top8.6 [SWAPPING PICKUPS {suspect one is bad}] You have 2 pickups. You can use the good one to test your "Bad One" theory. Simple: *** NOTE: DON'T SCREW THIS UP !!!! *******
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (24 of 43)8/6/2005 7:13:08 AM Ignition FAQ If you keep a spark wire connected and start the bike with the pickups swapped ..... the bike WILL misfire B A D L Y - Pull BOTH!! spark plugs off. Insert screw into inop plug wire & position near ground. - Swap the pickup sensor wires in TCI 4-prong plug. Plug White wire onto Red pin and visa versa (Red wire onto White pin). - Crank engine. If the bad plug fires (and good one doesn't) then suspect the pickup ( OR COIL) is bad. Test/Swap coil now and you'll know for sure. top8.7 [TEST FIRING a CDI or TCI] Obviously, if you can test fire the ignition module..... it narrows your troubleshooting quickly. Anotherwords... how can you "trick" the ignitor into thinking the pickup sensor has "pulsed" and/or get it to fire a plug? If your super lucky...your workshop manual will detail how this can be done. My 1973 outboard CDI could be fired manually and it was part of the factory service guide. The problem is.... there's no universal solution that I know of yet.... Certainly, you're not going to risk frying a good ignition module by trial and error. AND... unfortunately, the workshop manuals for most ignitors don't include this. I will pass on a backyard trick as told to me by "roadrunner" but I HAVE NEVER TRIED. But it sounds like it should work. He writes: "Just a quick backyead test. you can use one of them soldering guns, you know the hi current pistal type. It will trick the magnetic pickups to send pulses. becouse the gun creates a dense magnetic feald around the tip. Carfule not to burn something doing this. The pickups will sense these magnetic fealds and send firing pulses at 60 hz to the module . It makes it a lot easer to troubleshoot without kicking the starter each time ." top8.8 [HOW TO REPLACE THE PICKUPS] Get Haynes or Factory manual for this one. I will say this though. You must take GREAT CARE!! putting the crankcase cover back on and also how you seal (and sealant type)the wire bundle from the sensors out of the engine crankcase. If this is not done correctly you'll end up with an oil leak out of the crankcase and have to do it all over again. top8.9 [BAD NEWS ABOUT PICKUPS] The pickup sensor can fail and take the CDI with it (or visa versa). In other words, they can kill each other. Especially if a transistor shorts 12 volts through the pickup coil (you'd probably see an "open" pickup coil). Or, the pickup coil shorts to ground at higher temp and fries the transistors. file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (25 of 43)8/6/2005 7:13:08 AM Ignition FAQ top #9=> CHECKING TCI MODULE file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (26 of 43)8/6/2005 7:13:08 AM Ignition FAQ top9.1 [TCI MODULE 6-PRONG PLUG] Disconnect the 6-Prong plug from the TCI module, Key ON, and check at the plug: RED/WHITE striped = +12volts = power for TCI BLACK = -12 ground = ground for TCI and pickups ORANGE = +12v = power from Front cylinder coil primary winding GRAY = +12v = power from Rear cylinder coil primary winding BLACKWHITE = side stand relay wire. Should NOT be ground or +12 (side stand up! ). YELLOW/BLACK = Rev limiter wire. Cut this + tape ends. Should NOT be grounded!!
file:///E|/_WebPages_Posted/JetAv8rNew/Vision/IgnitionFAQ.html (27 of 43)8/6/2005 7:13:08 AM Ignition FAQ top9.2 [TCI MODULE VOLTAGE DROPOUT TEST] Check that you don't have a bad wire or connection to/from TCI. You are looking for voltage "dropouts". You should not see more that 1/4 volts in these checks. More means you have a wire or connector that is literally diverting power or making a poor ground. >> Set voltmeter to low scale 1-3 volts. >> Put RED test lead on +12 battery post. Put black test lead on these TCI pins with wires connected : RED/WHITE striped , ORANGE , GRAY wires top9.3 [CHECKING THE TCI WHILE