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2G "Limp Mode" Like symptom EDIT: Injector Circuit Malfunction

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CdubsBlackTalon

CdubsBlackTalon

Probationary Member
12
2
Feb 1, 2016
golden, Colorado
Hello! I have been reading various similar threads and trying various things to help with the issue, but so far my searches and reading have not led to an answer for my issue.

Recently got my Talon going last year and everything was great until recently. I was running some errands and stopped off at a store. When I started the car, it seemed like it was running on 3 cylinders. AFR was around 18+ and had almost no power at all. Limped it home. Since then it seems the problem is random. I had everything going good for about a day and then it came right back. It feels like a limp mode has been activated somehow and I cannot figure out from what. Injectors are new (after the issue) plug wires are also new with new plugs, gapped correctly at .028. Doesnt seem to be caused by heat as it will do it upon startup after being parked for a week or 2. I have not done a boost leak test recently, but compression is good as well as leak down test is good. I really feel it is electrical, and I am not very good with electrical issues.

I realize my description probably sucks, so any questions that will help me diagnose this would be most welcome. Profile is accurate but might not be fully comprehensive. Im sure ive left things out. I can also post a log if it will help.
Thank you in advance

Cody
 
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This sounds like you're getting a P0300 "random misfire" code. Your profile says that this is a 6-bolt swap with ECMLink.
Try unchecking the "Cylinder Misfire" box on the Misc tab in ECMLink.

With a 6-bolt swap, you have to use a 1G CAS. The 1G CAS is not compatible the 2G ECU's misfire detection circuitry. This will show up as false misfires. The ECU will then turn off the injector for the cylinder that it thinks is misfiring the most. It does this to prevent overheating the catalytic converter with too much unburned fuel and for emissions. When the ECU detects false misfires and turns off an injector, it will cause a wideband to read extremely lean.

The ECU will only check for misfires after a fully warmed up, 300 second, closed loop highway cruise. It will not check for misfires at idle or WOT. Turning the key off and then back on will reset the ECU until it completes another 300 second drive cycle. Unchecking the "Cylinder Misfire" box will stop the ECU from checking for misfires

Jim
 
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Thanks for the reply Jim!

I will give that a shot in the morning when my neighbors start to get ready for work. It does give me a random misfire code, but also sometimes cyl 1 misfire as well as 3. Mostly random though. I dont believe that will fix my issue. Ill have to add it to my profile, but I am running a 2g crank sensor and 2g CAS. Kiggly makes a bracket for the 6 bolt for the crank sensor. So that system should be stock. Also, I cant tell if anything resets this issue. Turning the key off for any amount of time does not seem to make it better or worse. It starts up with a weird sound and vibration. like a cylindar is gone.
 
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So that is a negative on the misfire check box. Still same symptoms. I have a short log from a trip around the block. Doesnt include startup but there is no change from startup till the log starts. Im sure a lot of things are off on the log, but i dont see anything that would cause my issue. I can post a video somewhere as well if it would help
 

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  • log.2019.08.12-03.elg
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Alrighty, so it threw a code other than cyl 2 misfire or random misfire, injector circuit 2 malfunction. Removing the injector clip from the injector doesnt change how it runs. If i unplug any other injectors, it shakes and chugs. So. Injectors are new. I have replaced the injector plugs as they were original and had wires showing where they met the plug. The connections to the harness were soldered. I checked voltage at the plugs with the key on and got ~12 volts on each wire on each plug. I checked voltage while it was idling between the 2 wires on the plug and each injector showed around 3 volts, with cyl 2 injector showing around 0-1 volts. Mostly 0.

Where do I go from here? Pull the ECM? Do I need to check voltage somwhere at the ECM? Really at a loss if anybody has a direction I could go in, it would be much appreciated.
 
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Updating in case it helps anybody. Ground wire on the harness side of the knock sensor was broken off the connector. New connector and so far no more misfire issues. Will update if anything else pops up.
 
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