Where's the power????

[ronhall512]

I have a 2004 GTO M6 car with 228\230 cam and ported heads.
I can't get it to turn up she feels like a turd no power but engine runs good.
It has no HP feels like I'm pulling my boat behind it and it turns up slow.
From a dig it falls on it's face

It ran better before all the work.

Jesse did me a starter tune and when I first flashed the pcm it ran like a raped ape then it set a P0100 MAF code I cleared the code and Iv'e done everything even reflashing it but I can't get that power back.


Thanks in advance for any help.

[Texas Terminator]

TQM? any other codes setting? did the P0100 come back? if so, is all of your intake plumbing tight? getting any KR? if so, anything loose or hitting the motor?

[superls1]

Can you post or email a scan. There are way too many possibilities, but if you say it did run like a raped ape hopefully we can figure it out. Are you sure about the code? Was it P0101? You may need to test/verify your MAP sensor to ensure that it is functioning properly.

Some info regarding a P0101 error:
The MAF system performance or rationality diagnostic uses the manifold absolute pressure (MAP), the IAT, and the engine speed to calculate an expected airflow rate. The PCM then compares the rate to the actual measured airflow from the MAF sensor. The PCM only compares the actual MAF value and the calculated value during conditions where the values are likely to match. This DTC sets if the actual MAF reading is not within a predetermined range of the calculated reading.

[BowlingSS]

You need to do some logging first to try and determine what is going on.

Bill

[ronhall512]

Sorry it's a P0101 MAF sensor performance.
It came back.
I can't help but think that the difference in the cam is throwing the readings for the map out of range and all the extra air moving across the MAF might be causing it to go out of range as well.
It seems like it did it only when the weather here was below 40 degrees.
That still don't explain where the power went I did the usual test like cyl bal to make sure I didn't foul plugs or something stupid like that. Today I'll pull them out just to make sure.
I'll also do a couple runs and get some data logged.

Thanks for the replies.

[GMPX]

Not sure what the US spec GTO is like, but the local version (Monaro) with ETC has a bunch of torque limiting tables active.
Also, the MAF thing, the one that normally causes problems with a cam fitment is table C6101, though that sets a different DTC from memory.

Cheers,
Ross

[Brains]

The 04 GTO is still a cable-driven throttle, but there's still a LOT of torque limiting going on. I relaxed the limits a bit on mine, and tossed in 4 degrees of timing at higher loads, and it really woke the car up -- and mine's stock Removing torque limiting from the 1-2 shift makes a lot of noise ... lol

Really feels good with a 100 shot of gas on it too

[ronhall512]

Looks like I have a problem in the right bank cyl bal was good but I went back and not much flow at all out that side. I suspect the converter.
I guess that's what you get when you run em too rich and still have the cats on.


I'll post later today with my findings. I'm waiting for it to cool off so I can pluck the O2 out and see what happens.

Thanks for all the replies.

[ronhall512]

Right bank converter fried.