Idle Relearn / Pedal Dance

[ChrisS]

TLDR - I'm looking for tips / experience with getting the idle speed to set with engine swapped cars.

I'm running a B15 Sentra racecar with a VQ35 swap. Originally a 2007 Altima 3.5 manual powertrain, and now a 2010 Maxima engine & PCM. It's still running on the modified Altima engine harness, with the exhaust cam sensors and actuators spliced into the harness. The Altima setup worked great (until it snapped an intake camshaft) and only idled moderately high (~1000 rpm) but with the Maxima hardware and PCM it now idles around 1500 rpm.

So far I've been unsuccessful getting the idle relearn to work; either by the pedal dance (...but I don't have a check engine light/cluster), or triggered with a scan tool. I've tried the process with both PCMs, in case the Maxima PCM wants some data from the CVT that is preventing the relearn. I do have some diagnostic codes disabled, including one that's TB related (because I have the TB motor power supply (PCM pin #2) connected to kill switch power (basically always hot) rather than the PCM controlled throttle control motor relay. Adding this control relay in and re-enabling that code is next on my list of things to try.

Has anyone else doing swaps run across this before?

Thanks,
Chris

[macdub]

Same issue here. The idle air volume relearn procedure fails if the idle is out of spec... a bit of a catch 22 really. Watching.

[ChrisS]

If your idle is too high (more than 1200ish I think) you can bring it down within the threshold by unplugging injectors. Do the relearn, plug them back in and repeat as necessary.

This didn't work in my scenario; I expect there is some missing or out of spec since it's a swap.

[macdub]

That's a good suggestion, thanks. I'll try it.

[Ludo80]

check for leaks around the plenum or throttle body if idle is too high