I've read many, many other threads here on this topic. There's even another "mystery" thread I just read through. Let me state what I have and what I have checked. Let's see if I missed something.
I have an 06 Scram.
1. First I had the intermittent running/starting issue that seemed like the pick-up coil issue. Died on me several times on a ride.
2. Brought it home and started reading.
3. Bike would start sputter, then die after 2 to 7 mins. Had spark at this time, but spark looked yellow and weak to me. Thought it was a fuel issue, so I went through carbs, but everything looked fine.
4. Then I set the pickup coil gap to 0.8mm
5. Then after that, no spark. (Logic says I screwed something up when setting gap, so I re-removed side cover again and checked everything. Everything looks fine.)
6. So far I have:
- FYI, the bike cranks over fine
- Tested for spark with all safety switches in both positions, no difference
- Battery voltage is ok
- Spark plug wires look fine meas'd ~ 5.5 ohms
- Coils looked ok ( I think) both meas'd 0.8ohms between + / -
- Meas'd between - lead and coil output and got 8.5Kohms
- Put one coil on another bike and I DO get spark, although it again looks yellow / weak to me, but definitely I get spark though.
- Meas'd pick up coil, it meas'd 623Ohms. When cranking it output a steady 1.5 ACV.
- Bought a new CDI (since there's no way for me to test it) Put in a new CDI, and absolutely NO change.
- Put coil from other working bike on this Scram and get ZERO spark.
- Have good ground / voltage at CDI (it's battery voltage)
- No fuses are blown, all lights work, all relays work.
- Crank sensor leads to ground look fine (no continuity)
- This bike has no alarm conn. It was cut out and all wires were soldered together more than one year ago. Bike has been modified but has ran fine for more than one year.
Am I missing anything? What else can/should I check?
Did you take measurements both hot and cold? Pickup coils are notorious for bombing out when they heat up, then working again when cooled. After taking the cold reading, throw the coil into a jug of boiling water for a couple of minutes then take another reading.
Am I missing anything? What else can/should I check?
There's very little else left to check. An ignition coil can still be bad even with correct resistance readings, but its very unlikely for both coils to cop out at the same time, that would be the daddy of coincidences. With one duff coil the motor should still spark up on the other cylinder.
Also try disconnecting the throttle position sensor.
Is there voltage at the coils (Red wire)? If not, or it is low, this comes from pin#1 of the alarm connector, so a check on all of the joints where the connector was cut out would be needed. You can't rule out something just because the bike ran on it for a year, connections and joints can go bad or break.
Did the bike die every time after a few minutes? Was there ever an instance when it either wouldn't run at all or kept running? - Back when it would run, sometimes it would idle well in the garage for several minutes. Then I would think it was ok. As soon as I would try to ride it and put the engine under load it would sputter and then eventually die.
Did you take measurements both hot and cold? Pickup coils are notorious for bombing out when they heat up, then working again when cooled. After taking the cold reading, throw the coil into a jug of boiling water for a couple of minutes then take another reading. - I did read much about this, but most of what I read said the coils wouldn't work when hot. I was planning on doing this back when I had a running / sputtering issue. Now though, that I have a no spark / no start issue I have not done this test. The coils never get hot in my case, and they work when installed on a different bike. Does this make sense or am I missing something?
There's very little else left to check. An ignition coil can still be bad even with correct resistance readings, but its very unlikely for both coils to cop out at the same time, that would be the daddy of coincidences. With one duff coil the motor should still spark up on the other cylinder. - These are my thoughts exactly. I can't believe that both coils would go bad at the same time. I'm leaning towards the crank sensor but trying to avoid spending without proper root cause analysis.
Also try disconnecting the throttle position sensor. - Ok, I will def try this, but I cannot see how this could cause no spark. I can imagine this would cause poor running but not no spark. Again, though I will try it.
Is there voltage at the coils (Red wire)? - Yes, I have battery voltage at the red wire at the coils. I also have checked the signal wire to ground with the key on and I have battery voltage there as well.
If not, or it is low, this comes from pin#1 of the alarm connector, so a check on all of the joints where the connector was cut out would be needed. You can't rule out something just because the bike ran on it for a year, connections and joints can go bad or break. - Oh believe me I know. This bike is fairly customized and I have already spent much time probing for continuity, resistance, and cutting off heat-shrink to inspect solder joints. So far everything looks fine. I was quite meticulous when I modified the wiring harness.
Good post, its not often that folk supply that much info about what has been checked so far.
See that you have full battery volts at the coils +12 terminals, that's the red wires. The reading should be the same as on the igniter's number 2 terminal.
There's the possibility of dirty or burned contacts at the ignition switch. Because the igniter is not drawing a lot of power with the engine stopped, you could see 12 volts there, but dirty, high resistance ignition switch contacts would soon make the voltage available drop once the engine cranks and the igniter starts to supply a considerable current to the coils.
See what the voltage at coils red wires is as the engine cranks. Here's a case where dirty contacts caused weak spark with advice on ignition switch dismantling, checks, etc.
Forchetto, how interesting you would immediately mention the voltage at the coil and at pin #2 on the CDI. Truth be told. I did measure 13.4V at the battery earlier. Then I measured 13.something at the red wire at the coils. Then I measured exactly 1 volt less on pin #2 going into the CDI. After much screwing around and checking everything. The last thing I did before posting up was to strip off some insulation from wire #2 at the CDI. Then I installed a wire directly from the battery to the CDI. Now I was definitely getting battery voltage to the CDI, but still no joy. It made no difference.
Also I measured 0.1ohms from my meter leads, therefore I measure 0.7 from the coils. This surely must be close enough right? I am guessing that if I measure 0.7ohms, that I should get spark but perhaps it is not optimal.
Also I measured 0.1ohms from my meter leads, therefore I measure 0.7 from the coils. This surely must be close enough right? I am guessing that if I measure 0.7ohms, that I should get spark but perhaps it is not optimal.
You seem to be pretty competent so I hope I'm not being silly suggesting to check the HT wires and their connection both to the coils and to the plug caps. Make sure the leads are contacting the HT coil posts and the plug caps are "screwed" into the HT wire conductors, the plug caps have a sort of self-tapping screw terminal that screws into the leads.
At this point I am not suspecting the ignition to be corroded. I turns over fine, and all lights, light up fine, and I measure battery voltage at fuse #5. Or am I missing something?
Anything else I may check? I did modify this loom quite a bit. I have relocated the starter solenoid, remove the security connector, added a RR from a modern Yamaha (relocated under the seat), removed all smog related stuff, blocked all unnecessary vacuum ports, etc. I was quite meticulous (I think) when I did all this work. I use solder or crimps where appropriate, and adhesive lined heat shrink. I still can't see how anything I did is causing ZERO spark. Weak spark sure, but no spark?? I am one to not believe in coincidences...so I am still leaning towards to coil pickup even though itr measure ok. It was right after I set the gap to 0.8mm that I went from (what I think was) weak spark to no spark. I do still need to do the hot coil test as Ripper mentioned though.
I refer to the following quote in your previous reply to me:
Did you take measurements both hot and cold? Pickup coils are notorious for bombing out when they heat up, then working again when cooled. After taking the cold reading, throw the coil into a jug of boiling water for a couple of minutes then take another reading. - I did read much about this, but most of what I read said the coils wouldn't work when hot. I was planning on doing this back when I had a running / sputtering issue. Now though, that I have a no spark / no start issue I have not done this test. The coils never get hot in my case, and they work when installed on a different bike. Does this make sense or am I missing something?
I would just like to point out that I was referring to the pickup coil, aka. crank position sensor, not the ignition coils. This is the same coil that you set the 0.8mm gap on. When one of these is faulty it can stop working as the engine warms up, then work again when cooled. That is why two resistance readings, hot and cold, are required. Without the pulse signal from the pickup coil, the igniter cannot fire the ignition coils. You can still do the test whether the coil is working or not. If the coil is not working your resistance reading will be infinity, or '1' on a digital multimeter set to the 2kohm range.
I've removed ~ 40lbs so far and added back about 18lbs (excluding the exhaust)
I've got ZRX rear shocks with racetech kits, and CBR F3 front fork internals.
BTW, the F3 forks are the EXACT same length as the stock Scram forks. That is not written anywhere as far as I can tell. The CBR forks are longer than the stock Thruxton forks, but they work perfect on a scram.
Ok, I just finished the boil test. If I have understood correctly, then I believe I do not have a pickup coil problem. I thought at some point it would go open, if it were bad. Do I understand correctly?
Forchetto has done more with these coils than me so he's more authoritative, but it seems to me that the resistance goes out of range at about 70 degrees. The coils are about 600 ohms +/- 10% and should stay the same, give or take a few ohms, right the way up to boiling point. Most do go open but thare's been a few that have still shown a high resistance. Forchetto! We need your input!
What about this business of the seat pushing on the CDI connector and it causing problems? Anything specific to look for? Although at this point I have no spark and the seat is off, and the CDI connector feels tight.
The tell tale signs of that are scuff/rub marks on the underside of the seat pan, in the exact place of the connector. Bikes that have suffered with this will typically run okay until you ride it, then when your weight causes the seat to rub on the connector, the bike runs as rough as a bear's ass. Eventually the connector fails if it gets too bad.
Here's another question. When you buy a new procom CDI, does it come ready to go? Plug and play..or do you have to download to it first before you use it? This bike came with a procom CDI, which I have never touched. If it went bad, and then I bought a new one and plugged it in and it didn't work, did I miss anything?
If you had to change the igniter, you would do much better by getting a Fire Starter from TTP. Mike (aka Pieman) from TTP is a member here and you would have the benefit of his advice. But I believe that the Procom units do come ready to go.
What about this business of the seat pushing on the CDI connector and it causing problems? Anything specific to look for? Although at this point I have no spark and the seat is off, and the CDI connector feels tight.
Here's another question. When you buy a new procom CDI, does it come ready to go? Plug and play..or do you have to download to it first before you use it? This bike came with a procom CDI, which I have never touched. If it went bad, and then I bought a new one and plugged it in and it didn't work, did I miss anything?
The pick up coil resistance does seem a bit high. I'd expect the value to rise with temperature but not that much.
The quoted resistance to be expected is 560 ohms +/-10% at 20ºC .This means you should see somewhere between 504 and 616 Ohms. If you measure it with the engine hot the resistance would be higher, as much as 640 Ohms or so.
Thank you for your input. After I check the CDI programming and CDI connector one last time, if there's still no joy I will go ahead and order a new pickup coil.
Ok, still no spark. I now have a brand new pick up installed @ 0.8mm. I have two CDIs to try, and I have a working coil from another bike. If / when I try any combination of these items and I get ZERO spark.
I get 12V on the read wires at the coils.
I get 12V to the CDI, although I do measure 1 volt less than battery V? For now though I manually jumper this to get battery V to this wire, and it makes no diff. Still nothing..
The coil resistances seem ok, cannot remember the number tho? What should they be?
The Triumph manual I have says I should measure .1 to .2 ACV at the CDI conn, pins 5&6 from the pick up coil. What I measure is 2.2 ACV. Is there a mis-print or am I missing something here?
What else?
This bike is wearing me out mentally. Call me crazy, but I like riding them, not fixing elec gremlins..
The Triumph manual I have says I should measure .1 to .2 ACV at the CDI conn, pins 5&6 from the pick up coil. What I measure is 2.2 ACV. Is there a mis-print or am I missing something here?
Get your mental equilibrium back! Just calmly remember what you are trying to do.......to isolate the problem. It cranks over and you have battery voltage at the coils. Have you done a simple continuity check on the return to the CDI? I take it you have. If so, you have an energised ignition and have narrowed this down to a 'trigger' problem i.e.
The power is either not being cut to collapse the magnetic field in the coils
or the ignition coils themselves are kaput
or the pick up coil is u/s
Or you have a break somewhere in the loom between those components.
At this stage of the game I would do simple continuity checks on all the wire feeds (use a dress making pin through the insulation at the CDI end and a multimeter with buzzer - it is great for confidence!). Check pick connector to CDI from the plug back as well. Once you have proved all the wiring you can revisit the components. It is tedious but if you are systematic you WILL trip over the problem even if it takes more component swapping.
I would add that, if at all possible, test your components on a working bike. You will then know they are ok. The reverse may not be true if you actually have two problems, not one!
Callumity and Tornado, I thank you so much for your responses. These are helpful things you are stating.
Although I still have no spark..
I have continuity from: CDI conn to coil for both coils. Pickup conn to CDI. TPS to CDI.
I just checked from the Pickup conn pin #2 to ground with the battery off. The manual states you should get continuity, but that if you measure a resistance you need to replace you CDI. Well I just tried this with both CDIs. Both CDIs have my cont tester beeping, but with both CDIs it also shows a resistance. Funny the new CDI shows are slightly higher resistance.
I tested the coils on a different bike and they both work.
I just checked the ACV at the trigger wires at the coils. 0.1 ACV or greater is the limit, and I measured 0.12 and 0.098. I assume this is good enough to get any spark at all, even if 0.098 may be marginal.
Again, I measure 2.2 ACV, when cranking, and measuring the pickup conn when it is disconnected from the CDI. Whereas the manual says I should get 0.1 to 0.2 ACV.
I also undid a lot of electrical tape and inspected and probed many other wires. So far everything looks fine.
I already bought a brand new igniter and installed it. This is what I was speaking of in my earlier post when I said I had two CDIs. I didn't mention I guess that one was brand new. Do I understand correctly: When you buy a Procom you just plug it in and go? No need to download anything right?
I too, am haunted by this condition. It's been so long I can't recall all the testing I did. At one time I ran a redundant ground to the neutral switch on the bottom of the bike and it fired right up! Voila! But no lasting fix. Rats! I did encounter the "only one cylinder firing" along the way and a new ProCom unit resolved that issue. (I do remember setting the dial on the ProCom to correspond with the number on my stock igniter). Have also replaced coils. Then, for no known reason the bike ran for about one year just fine. Then, last February, the same 'crank/no spark' condition returned and I have not gotten back to the bike since. (But I have finished and driven my 1965 GTO a bunch !!!) So I have read so many of these threads about the 'same' condition and I only remember one fix: a few different components were replaced together and that solved this for one member. Eventually I will get back to this scooter, but I am not getting any younger. (See thread about average age of the America rider !!) I wish you the best of luck with this, and please do post when this issue is solved for you.
I too, am haunted by this condition. It's been so long I can't recall all the testing I did. At one time I ran a redundant ground to the neutral switch on the bottom of the bike and it fired right up! Voila! But no lasting fix. Rats! I did encounter the "only one cylinder firing" along the way and a new ProCom unit resolved that issue. (I do remember setting the dial on the ProCom to correspond with the number on my stock igniter). Have also replaced coils. Then, for no known reason the bike ran for about one year just fine. Then, last February, the same 'crank/no spark' condition returned and I have not gotten back to the bike since. (But I have finished and driven my 1965 GTO a bunch !!!) So I have read so many of these threads about the 'same' condition and I only remember one fix: a few different components were replaced together and that solved this for one member. Eventually I will get back to this scooter, but I am not getting any younger. (See thread about average age of the America rider !!) I wish you the best of luck with this, and please do post when this issue is solved for you.
I am very close to just bypassing a bunch of wiring myself to see what happens. I'm real tired of looking at this dis-assembled rats nest sitting in my garage..
TO ALL WHO HAVE REPLIED TO THIS THREAD: When I bought this bike it came with a Procom CDI installed. At one point previously, it had some issue and I set the rotary switch on the CDI to position 0, so I could download a new map. I didn't realize at the time that I should've remember what position it was at to start with. So I ended up setting it to position 6, which is listed as being a mildly modified machine on Procoms webpage. Could any of my issues, with this bike, be related to me not having the original CDI, and not having any clue what position the CDI should be set at? Before when the bike was running, it would run on all positions, but 6 did seem the "best."
How can I figure out for sure what position it should be set at, when I do not have the original CDI? Can I use my VIN to figure this out?
I have tried contacting Triumph America for technical stuff in the past and got nothing from them. Maybe you have a friendly dealer who could work some magic for you. Your description of setting #6 working the best sounds like a good place to go. Might give the ProCom folks a shout also. Having thought about this some today, I recalled another member who said he/she traced a wire from the headlight and found a bad solder connection was to blame.
While working on mine, I found with the scooter running, I could wiggle the harness a few inches away from the igniter and got the engine to stop dead about six times in a row!! I wanted to pin-out the wires from that connector to check them but was unable to do so. Also checked my diode pack and it tested O.K.
... I found with the scooter running, I could wiggle the harness a few inches away from the igniter and got the engine to stop dead about six times in a row!!
My '05 Thruxton did exactly this back in '08 (so just out of warranty :frown2, eventually killing the igniter. I stripped back the cover on the harness to the igniter plug and wiggled the individual wires until I found the culprit - it turned out to be the red wire to pin 2 which supplies the +12V to the igniter (without this the bike will crank like a champ but you'll never get a spark). I stripped the harness further back from the plug expecting to find a poorly crimped connection - but everything was good.
I disconnected the igniter plug (for the first time since the bike left the factory), took some hi-res photos, and zoomed in - the contact for pin 2 was ever so slightly bent further back than the others. A 'quick-and-dirty-get-u-home' (tm) repair was applied (I stuffed the tail end of the smallest zip tie I could find down the back of the plug to push the connector out again) and she's still running like a champ after a complete harness re-wire, two engine rebuilds, and three different igniters.
2.2v AC makes sense given you have reluctors passing a magnetic coil and generating a small signal current to the igniter. It makes sense in the context of the limitations of your multimeter! It should be measurable but not with any great accuracy from a simple $30 diagnostic multimeter. The igniter imposes a mapped time delay to the spark according to engine speed and some reference to load from the TPS but not throughout the rev range.
From everything you have described I would be testing your igniter on another bike......on the balance of probabilities because it is the most likely culprit and not because you have revealed its guilt!
At the end of the day, this bike cranks over very well, but gets no spark. I test the output from the igniter to the coils and I do get greater than 0.1 ACV as the manual states. Also I'm getting battery voltage to the other input into the coil. I take the non-working coil(s) off this bike, put them on another bike and they work fine. Put the coil from the other bike on this non-working bike and it doesn't work.
If you know your coil can make spark, and you know your getting both battery voltage and proper ACV to the coil, what else is there? Maybe th AC signal I am measuring is improper, but I just can't see it with a simple DMM?
The safety switches earth out the starter circuit so it will neither turn over nor spark. Everything you describe sounds like an internal CDI issue (discounted by testing on a known good bike) or a continuity issue in the loom or connections and specific to the energising and/or switching of the coils.
I have two CDIs now. The one that came with the bike and a brand new one I just bought. Both deliver the exact same result. Again I measure > 0.1 ACV at the signal to the coil. So again I ask (sort of rhetorically..) If I measure +12V and > 0.1 ACV at the leads plugged into the coil, while cranking the bike, why would I get no spark? Is the AC signal out of phase, or what? That's all I can think of. During cranking the +12, doesn't not change, so that isn't grounding out. Not too clear about the AC line though, I just have a DMM, which I am sure measures RMS.
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