The Ghost in the Machine Continues... random richness

[silviasgp06]

if you read my most recent posting before this, I recently preformed a boost leak test. Found a boost leak at the adjusting screw to the FPR but other than that the car check out for boost leaks.

Still having richness issue though!

Its like there is a boost leak but its intermittent.

Last night coming back from ROTC I accelerated to get onto the freeway and it appeared to be running just a little richer than normal but otherwise it was ok.

Then a few minutes into the drive I saw my AFR gauge sweep over to 10 afr(the AEM uego max rich reading) and the car began to bog down. I had to give it more throttle(which also spooled the stock turbo) to keep from slowing down. In the past when the car was all fine the car normally cruises at less than 10% duty cycle, to keep the car at speed I had to add more throttle which resulted in in >20%+ish duty cycle on the commander.

It felt like a boost leak, which I figured it was but the more I drove it on the 30 mile drive home the better the car ran and responded.

What Ive done recently that may be related to the problem:-The other day I cleaned the MAF with MAF cleaner but It drove fine before last night-When messing with the FPR to fix the leak I re adjusted the pressure cause it was a little low

My thoughts:-What are the chances of this being an fpr issue? Like a bad diaphragm or something.Unfortunately they do not sell rebuild kits for this fpr. I plan on opening it up when I get done with work to check. -or Maybe my MAF is slowly going bad

So what do you guys think?
Modified by silviasgp06 at 1:46 PM 4/11/2010

[Yellow4g63]

Whats the voltage? maybe the alternator is going bad?

[silviasgp06]

ill check on my next drive but,... how does a bad alternator relate to richness? Low volts messing with sensor readings or something?

[Yellow4g63]

low voltage would make the fuel psi lower and make the car bog out and start to sputter tho I never paid attention to the A/F raito at the time lol. What about the coolant temp sensor? that new or the same one that came with the motor set?

[silviasgp06]

I see, my understanding is that a lower fuel psi will not lead to richer mixtures.Well the sensor is the same as the one as the one that came with the motor set a few years ago. Im sure they go bad but how regular is this?

[silviasgp06]

happened again today on start up. ran so rich that the AEM wideband flashed 10afr.

volts are steady 14v

[silviasgp06]

narrowed down to a possible head to ex manifold gasket leak or a mani to turbo leak. Seems to make sense

[Yellow4g63]

Coolant temp sensor can make you car do funny things. If it's bad the computer won't know that your car is already warmed up and dump extra fuel. I changed mine a few years after I had my swap running. The 300zx one is a good replacment but I forgot which year it was Carl told me.

The exhaust leak at the turbo would kill power, do you feel it leaking by the turbo with the car on?

[silviasgp06]

I can only hear and feel the leak before the car fully warms up. Once the car warms up the leak seems to go away, most likely due to metal expansion of the two metals.

[Yellow4g63]

Try and tighten up the turbo bolts. When I took my stock turbo off I was shocked that I was missing one and the others were lose.

[meet07]

Try and tighten up the turbo bolts. When I took my stock turbo off I was shocked that I was missing one and the others were lose.

Hey yellow did you not have the factory turbo gasket? Mine has 4 tabs that fold over the nuts to help with the nuts backing off?