Reduced Power at WOT After Rebuild

[H8Rain]

2 years ago I put a Whipple SC on my car. Whipple tune. For a year car ran great! Long story short, I developed some internal issues which led to needed a new motor.

I bought a new LS3 from Jennetty Racing. I also bought a ton of other upgrade stuff from them to complete the build….. cam, headers, fuel pump, injectors, plugs, cai, catch can, etc. New GM wiring harness. I put the Whipple back on. JRE provided a tune via email based on everything I did.

Break in for about 800 miles not pushing it hard and keeping it under 3000 rpm’s. Car drove great! No issues. Changed the oil and ready for pushing it harder. I can push it moderately and no issues. But as soon as I push it harder it immediately goes into reduced power mode. Throws code P0606.

I took it to JRE for a basic routine inspection. The immediate response was my PCM was at fault. However Ted’s son (who is great) seemed very confident it was my aftermarket coils (which I was running with the original install of the SC no problem). He told me to switch them back to factory OE. So did that and out for a test drive and same thing is happing.

I’m having a hard time with it being the PCM when it was fine before. Been doing a lot of research and thinking there may be an issue with the tune?

Any thoughts or suggestions would be greatly appreciated!

Thank you!

[bsn]

Long shot but make sure you have a good ground between the engine and the body. A poor ground that opens during acceleration can trick the ECM into throwing a code.

[H8Rain]

I did clean all the grounds when I did all the wiring, but I’ll double check them!

[larry_g]

Why the new wiring harness?



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[H8Rain]

The original one was melted very badly on the passenger side. All new wiring, sensors and accessories when I installed the new motor.

[larry_g]

Originally Posted by H8Rain

The original one was melted very badly on the passenger side. All new wiring, sensors and accessories when I installed the new motor.

Time to double check all connections. It's possible the meltdown did some additional unseen damage (PCM) but it seems strange that it only happens under heavy load. Perhaps something is rubbing or grounding as the motor moves around a bit.

I'd also wonder if one of your sensors is out of range and triggering the error. For example you need to have the right MAP sensor for boost.

I assume they had you datalog when you recreate the issue.

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[gtstorey]

Melted harness could have shorted enough stuff to damage the ECM.

[H8Rain]

JRE provided a new MAP sensor for the build.

I haven’t done any logging. When I took it to JRE I thought they were going to hook it up to the dyno and do some data logging. But they never got that far. They just did the visual inspection and were fairly confident it was the aftermarket coils, which it turns out it wasn’t that case.

[gtstorey]

Have you looked up the GM diagnostic steps for the P0606 code in an OEM Camaro service manual? Might not be much since that code does seem to indicate an ecm internal fault.

[larry_g]

I'd still suggest touching every connector to make sure they're seated properly and visually confirm nothing is pinched or pulled too tight. I would then get some data logs and see if the tuner can point you in the right direction.

It's expensive to pay for dyno time just for diagnostics, but it may be what you need. I have worked with a couple of tuners over the years that were able to help diagnose an issue before we got serious about the tuning itself.


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