DomsE36Garage Posted June 9, 2020 Report Share Posted June 9, 2020 Hi Guys, I'm running the G4+ pnp for the M50 vanos motor. I was out at the track yesterday and the car was misfiring on Cylinder 1 each session which I identified after session 2. A bit of background is the last time I was out racing before Covid, my high mount turbo setup blew out the downpipe gasket and I had a small fire right next to cylinder 1 and coilpack 1. Once the downpipe blew out, the car sort of went into limp mode and I limped it back to the pits and put out the fire. I've since fixed all that and the car sounded like it was running fine, however out on the track yesterday, you could hear it clearly at full noise brumming away on 5 out of 6 cylinders. I tried multiple tests (swapping known good coil for the potentially bad coil, also the wiring loom to coil 1 was pretty toasted so I snipped out the bad wires and did some trackside rewiring with no luck). So I'm pretty sure the coil is OK as it ran fine on another cylinder, and I'm pretty sure the sparkplug in Cyl1 is ok because it also worked fine in another cylinder, so I'm trying to work out a way to troubleshoot this. Q1. A mate recommended I set a 'logged channel' to see the voltage output, or at least some output recorded by the ecu each time the coil fires to see what is going on....is this possible to do and if so, how do I do it? Q2. Also, he suggest I try to get the ecu to test the coils by firing them on command so I can test for spark....is this also possible and how do I do it? I also plan on doing a compression test and depending on the spark situation, i'll check out the injector on Cylinder 1 too....I can't think what else may be the issue but I have a very strong hunch that whatever it is was caused by the fire in the engine bay. Here are some pictures of what's going on there too (all the white stuff is fire extinguisher residue from months ago), hope you can help Cheers, Dom Quote Link to comment Share on other sites More sharing options...
dx4picco Posted June 9, 2020 Report Share Posted June 9, 2020 has the coil itself been replaced or tested with another one on that cylinder? Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 9, 2020 Author Report Share Posted June 9, 2020 Not yet, though I threw one of the working coils (from Cylinder 5) into Cylinder 1 and it still didn't fire so figured that was enough of a test (and vice versa, the potentially bad coil from Cyl1 fired fine on Cyl5). However tomorrow I plan on grabbing one of my spare old coils from the old motor and throw it in there to see if it makes a difference....i'm not hopeful though. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 10, 2020 Author Report Share Posted June 10, 2020 Any other suggestion for those couple of questions? Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 10, 2020 Report Share Posted June 10, 2020 15 hours ago, DomsE36Garage said: Q1. A mate recommended I set a 'logged channel' to see the voltage output, or at least some output recorded by the ecu each time the coil fires to see what is going on....is this possible to do and if so, how do I do it? Not possible, you will need a multi-channel oscilloscope for that. 15 hours ago, DomsE36Garage said: Q2. Also, he suggest I try to get the ecu to test the coils by firing them on command so I can test for spark....is this also possible and how do I do it? There is an ignition test function in the ignition setup menu/folder. How do you know it is cylinder 1 that is misfiring? Is 1 cylinder not running at all or only missing under high load? Many of those extinguisher chemicals are very corrosive to tin and copper so I would inspect all terminals/connections/splices that have potentially been exposed. They appear to be sealed connectors on the coils so they should be ok but give them all a close inspection. Those two ground straps on the center and back coil look potentially affected. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 10, 2020 Author Report Share Posted June 10, 2020 6 minutes ago, Adamw said: How do you know it is cylinder 1 that is misfiring? Is 1 cylinder not running at all or only missing under high load? So with the car running, I removed the plugs from each of the coils 1 by 1. Unplugging each coil made the engine sound different EXCEPT for Cylinder 1. So I suspect Cylinder one isn't firing at all, plus Cyl 1 is the closest to where the fire was, so I was initially drawn to that cylinder. I'll try a compression test first to make sure that cylinder is OK, and then I guess I have to start testing coils and wires etc, but certainly sounds like that's where the problem lies. I can send you a log output of the session when the fire occurred, and then the session with the missfire if you think that would help. Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 10, 2020 Report Share Posted June 10, 2020 Ok, if it not running on that cyl at all then that makes thing easier. Start with the ignition test on Cyl1. If some wires or the coil shorted it could have potentially damaged the ignitor in the ECU. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 10, 2020 Author Report Share Posted June 10, 2020 Is there an igniter for each coil on the ECU or a single igniter for all coils? I traced the wires back to the potential short and replaced them. I also replaced the coil with a working one and it's still not firing, I wonder if the short did damage the igniter, so if so, how would I check that? Quote Link to comment Share on other sites More sharing options...
dx4picco Posted June 10, 2020 Report Share Posted June 10, 2020 did you check for continuity from the ecu to the coil on the signal wire? did you check for the voltage on the power wire on the coil plug? did you check for the ground on the ground wire on the coil plug? These may be things to consider looking at Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 10, 2020 Author Report Share Posted June 10, 2020 1 minute ago, dx4picco said: did you check for continuity from the ecu to the coil on the signal wire? Not sure how to do this (i[m not electrically minded, so hints would be great) 1 minute ago, dx4picco said: did you check for the voltage on the power wire on the coil plug? Also not 100% sure how to check this either. I did a continuity test on all 3 coil plug wires, and two of the 3 have continuity to ground on the engine, the 3rd wire doesnt. (Test may be irrelevant but I get the same results on the working coil plugs) 3 minutes ago, dx4picco said: did you check for the ground on the ground wire on the coil plug? If the ground wire is either brown or green, yes, I checked continuity back to the motor succesfully. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 10, 2020 Author Report Share Posted June 10, 2020 Ok, looking at the wiring schematics: Green - ignition/12v power?? Black - signal to ECU Brown - ground So it looks like the black wire trails back to the ECU on pin 50 (i'll check continuity between pin 50 on the ECU plug and the black wire on the coil plug) How do I check 12v on the green wire? do I just test to a ground point to display voltage? For the brown, i can ground that to the engine no issues. Quote Link to comment Share on other sites More sharing options...
dx4picco Posted June 10, 2020 Report Share Posted June 10, 2020 that's seems the right thing to do yes. Ingition on, and check the voltage relative to a engine ground for example. If all 3 come back positive (continuity on signal, +12v and GND) then you will be more likely looking at an ignitor issue. I think there are indeed one ignitor per coil, to be confirmed by a link guy. Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 10, 2020 Report Share Posted June 10, 2020 To test wiring you could quickly short the wire on ecu pin 50 to ground (using a small jumper wire or paper clip etc), just a quick (few milliseconds) touch to ground, the coil should charge while that pin is grounded, and it will spark as soon as you release the ground. If you get a spark when testing like that then that would prove the coil and wiring is ok and the problem is likely the ignitor. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 11, 2020 Author Report Share Posted June 11, 2020 Yeah awesome, thanks Adam i'll try it out over the next couple of days to see how I go. Quote Link to comment Share on other sites More sharing options...
DomsE36Garage Posted June 13, 2020 Author Report Share Posted June 13, 2020 @Adamw Ok, so I did the wire on ECU pin 50 to ground and got a really weak spark on Cyl 1 coil and plug...so that's a good sign my wiring hack is working. I tested the same thing on Cyl 2 and got the same small little spark so that's good. I then plugged in the ECU and ran the ignition test on Cyl1 - No spark at all >>> Ran the ignition test on Cyl 2 - Really strong spark. So looks like I might have a Cyl1 igniter issue on the ECU. Can you tell me which and where the igniters are on the ECU and if the faulty/shorted one can be repolaced? I really don't want to have to buy another $1500 ecu if I can avoid it. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 13, 2020 Report Share Posted June 13, 2020 The ignitors are the 6 big fet looking devices beside the Aluminium bar heat sink. You would be best to get it back to Link for repair, they are difficult to rework due to all the heat sinking on that area of the board and there is some tricky assembly work. Quote Link to comment Share on other sites More sharing options...
Greenday Posted August 29, 2021 Report Share Posted August 29, 2021 Sorry to hear your bad luck. I recently experienced the same problem with the same ECU. No fire involved with mine. It had been working flawlessly for the last 2 years. Spent the last two weeks prepping for the dyno, went to drive it over to put it up on a lift to check everything underneath, and it started misfiring. Number one coil stopped firing. Swap coils, replaced plug, check for power, signal, and ground. Everything checked except for signal. Check continuity between the coil primary plug and ECU plug. Everything checked out fine. The dyno is scheduled in three days. And track day next Saturday. Guess I will not be making neither one. Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 29, 2021 Report Share Posted August 29, 2021 Note sure what your question is? It would pay to check at the ecu pin with an LED test light or scope before concluding it is faulty as these are pretty robust drivers and rarely fail. Contact [email protected] if you want to arrange inspection and repair. It will most likely take longer than 3 days however due to the slow shipping at present. Quote Link to comment Share on other sites More sharing options...
Greenday Posted August 29, 2021 Report Share Posted August 29, 2021 I did one better,oscilloscope. Quote Link to comment Share on other sites More sharing options...
Greenday694 Posted August 29, 2021 Report Share Posted August 29, 2021 This is my original sign in name. Quote Link to comment Share on other sites More sharing options...
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