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View Full Version : rb25 leaning out after warm up


alex37211
06-28-2010, 02:35 PM
I have an rb25det series 1 and it has been running lean since I got it. My spark plugs all turned white and it hesitates under load. I installed an innovate LC-1 wideband and it reads fine for the first minute or so until the cold idle falls and then leans way out to like 22. I replaced the fuel pump (walbro 255) and maf. Same symptoms.
Everything is stock and no trouble codes.
Any ideas / suggestions? Thanks.

confuzed240
06-28-2010, 03:28 PM
Did you check the MAF voltages to see if it is wired correctly?

alex37211
06-28-2010, 04:02 PM
what is the voltage supposed to be?

Oh and it had the original maf but I have just replaced it with a z32 maf and switch the middle two wires around.

Ghost240
06-28-2010, 04:06 PM
^^^That's why it's doing that.You need to tune for Z32

alex37211
06-28-2010, 04:19 PM
no it was doing the exact same thing with the stock maf and with no maf.

confuzed240
06-28-2010, 04:23 PM
It shouldn't run the same like that. With the MAF unplugged with should not be able to rev above 2000.

I know with all the 4 bangers you need to retune for the z32 MAF. I say search and find out what your MAF voltages should be.

alex37211
06-29-2010, 08:32 AM
It shouldn't run the same like that. With the MAF unplugged with should not be able to rev above 2000.

I know with all the 4 bangers you need to retune for the z32 MAF. I say search and find out what your MAF voltages should be.

I mean it would run really lean at idle even with the maf unplugged.

Darius
06-29-2010, 01:18 PM
Have you checked your intercooler piping for leaks? Does it go rich when you hit boost?

alex37211
06-30-2010, 01:12 PM
I'm not sure. I will try and see. I think Im gonna try that temperature sensor.

jetpower
01-04-2011, 01:00 PM
did you ever resolve the problem by replacing the temp sensor?