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ECMlink P0300 6 Bolt in 2G

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Proven Member
Aug 29, 2022
Royal Oak, Michigan
Hello Everyone,

I am running into an issue that I have not dealt with before, and I am not finding a good starting point through my searches.

Car is recently rebuilt with a 6 bolt in a 96 Talon.
ECMLink V3 installed.
GM 3.5in MAF
GM 3 bar MAP
MHI Small 16g
AEM Wideband simulating front O2
Stock throttle body, intake manifold

Attached is a log I took today.
I did not go into boost at all since the engine is still in the break- in period.
Around 10 mins of driving and I instantly got a MIL for P0300 and the car started to run very roughly. I was able to drive it slowly home but it was not happy about it.

I then turned off the car, removed the MIL code, and restarted it, after which the car ran perfectly fine again.
I had it idling in the driveway for another ten minutes but there was no real sign of a misfire or anything abnormal.
Car runs rich for sure, it needs to get tuned which I am doing next week.

I have checked that the O2 sensor is cycling properly.
There are no discernable boost leaks.
TPS, ISC, MAP, MAF sensors tested acceptable.
PTU replaced (no change to behavior).

I can check the coils and other ignition parts but I am not sure that is causing the issue, since it's not specific to a particular cylinder.

Any help is appreciated!


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Difficult to rule that out honestly. Car has been sitting all winter with about half a tank so it's possible. Although, it's fairly consistent after the car is driven and warmed up for about 10-15 mins.

Bad gas will show up basically instantly and it won't run correct from startup.

Disable the check for misfire and see how it runs to the point where it should misbehave.
6 bolt swaps into 2g with 95/96 ECUs regularly require random misfire check to be disabled due to the use of the 1g cas
Last edited:
Found at least what I think is the issue. More investigation to ensue, but here’s what I found.

Fuel injector latency was set incorrectly.
I have FIC 1050cc low-Z injectors and found a previous data sheet from another member to reference to.
There’s some more tuning to do, but was able to get a log of ~30 minutes and found no issues.

Will share more updates once I can check a few more conditions to verify this was the issue.
If you're still checking for random misfire in the ecmlink settings, changing your fueling a bit here and there isn't the ultimate answer.
Read this: specifically the misfire section.

Use non-95/96 cam sensor needs to be checked on the Misc tab, which it is in your log, your plug order needs to be rearranged, and the random misfire DTC is almost a guarantee to show up, randomly or repeatably, due to the ("less accurate") 1G cam sensor simulating both cam and crank signals. That's solved by simply not checking for it.

If it was a fueling issue that was causing that DTC, you'd be seeing it pretty soon after starting up and it wouldn't go away after you shut off the engine, especially if it was still hot when you restarted it. You'd also be seeing your trims entirely destroyed and it would run possibly run rough due to fueling that's outside of it's adjustable range. It wouldn't throw a misfire.

Looking quickly through that log, yes, you have some issues.

Your O2 is not cycling, so you're not able to enter closed loop
Your TPS settings are entirely bogus
Did you wire your wideband's narrowband output into your ECU's front O2 pin?
You have charging issue. I think that's causing the P0300 code.
After the engine gets hot, most of time you have the voltage too low. Either the alternator, voltage regulator, battery or ECU. You have to fix it first before messing with the tuning.
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