R33 Running Rough Only When Cold, Under Load

[jgtoranalc]

R33 GTST Series 2

Splitfire Coilpacks

660cc injectors

Fully adjustable Coilovers

Nistuned

Turbo Timer

Bosch z32 AFM

Gready Front Mount Intercooler

Boost Gauge

Boost Tee - Set to 13psi

Problems I am having is every time I start the vehicle when the motor is cold, it runs rough only when I'm accelerating and then once it is at normal operating temperature, it's fine to drive. Sometimes I will turn it off after a long drive (at normal operating temperature) then start car again and the Idle goes pretty high (can't say what to as tacho is inop.) It's like it thinks it's cold and putting more fuel in.

I replaced the spark plugs and they were all black.

When the motor was running, I removed a coil at a time but couldn't tell any difference as the problem only happens when motor under load.

I bought this car roughly 1 month ago and previous owner didn't tell me about this problem....very sneaky but got it cheaper than what he had the original price at.

Where do I go from here? What is the next thing to look at? Could it be simple as the tune not setup right.

Edited December 11, 2015 by jgtoranalc

[Ben C34]

Tune

[Hadouken]

Piston slap

[Piggaz]

As Ben said. Cold start tune is Rubbish/isn't done.

[admS15]

I have heard that nistune can be problematic on 33's. I wonder if that could be your issue. Your best course of action will be to get a tuner with nistune experience to take a look at it and see what's going on. Hopefully just needs a slight tweak.

[SkudR33]

+1 for tune - I was chasing my tail for months on a similar issue - turns out cold start map was poo

[jgtoranalc]

Thanks for that info. I will look into it and find a decent tuner who knows what they're actually doing.

[jgtoranalc]

I thought I'd update this thread for future use.

I did send my car to a tuner and they fixed the problem. No cold start issue anymore, they said it was running too lean, adjusted a few things, also checked the timing and idle too.

[dee242]

if u took your o2 sensor out put it back in