rb25 leaning out after warm up - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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

Quote:

Originally Posted by confuzed240

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?

06-28-2010, 02:35 PM	#1
alex37211 Join Date: Oct 2009 Location: Nashville TN Age: 36 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	rb25 leaning out after warm up 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.

06-28-2010, 04:06 PM	#4
Ghost240 Zilvia Junkie Join Date: Sep 2008 Location: West Chester, Pa Age: 35 Posts: 586 Trader Rating: (12) Feedback Score: 12 reviews	^^^That's why it's doing that.You need to tune for Z32 __________________ "Dare to bear the crown." Illantic.com

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06-28-2010, 03:28 PM	#2
confuzed240 Zilvia Member Join Date: May 2009 Location: Raleigh Age: 32 Posts: 178 Trader Rating: (3) Feedback Score: 3 reviews	Did you check the MAF voltages to see if it is wired correctly?

06-28-2010, 04:02 PM	#3
alex37211 Join Date: Oct 2009 Location: Nashville TN Age: 36 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	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.

06-28-2010, 04:19 PM	#5
alex37211 Join Date: Oct 2009 Location: Nashville TN Age: 36 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	no it was doing the exact same thing with the stock maf and with no maf.

06-28-2010, 04:23 PM	#6
confuzed240 Zilvia Member Join Date: May 2009 Location: Raleigh Age: 32 Posts: 178 Trader Rating: (3) Feedback Score: 3 reviews	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.

06-29-2010, 01:18 PM	#8
Darius Zilvia Junkie Join Date: Mar 2005 Location: Chicago Posts: 346 Trader Rating: (5) Feedback Score: 5 reviews	Have you checked your intercooler piping for leaks? Does it go rich when you hit boost?

06-30-2010, 01:12 PM	#9
alex37211 Join Date: Oct 2009 Location: Nashville TN Age: 36 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	I'm not sure. I will try and see. I think Im gonna try that temperature sensor.

01-04-2011, 01:00 PM	#10
jetpower Leaky Injector Join Date: Mar 2010 Location: SA Posts: 146 Trader Rating: (4) Feedback Score: 4 reviews	did you ever resolve the problem by replacing the temp sensor?