Problems going lean.. PLEASE help!

[kjzstealth]

I had a hotwired factory pump and was running lean at 12 psi, so I installed a walboro fuel pump.

It ran awesome for one drive, but when I stopped, my car was smoking from the speedometer sensor. I got it unplugged and put everything back together which, of course, reset my ECU.

Now it is running lean again. Anything past 9 psi and my AF goes over 12:1.

I have had to replace one engine and I don't want to have to do it again because of this.

Any ideas on why this would be happening?

[Trab]

Have you tried changing your fuel filter? I doubt this is it but would be a good thing to do. Also maybe look into trying out another FPR.

[Atrosity]

Are you able to post up your datalogs?

[CoreyB]

Boost leak ?

Edit : Never mind, that would make you rich.

[91STT]

Have you checked fuel pressure yet?
When you installed the new FP did you make sure the O ring did not "fold up" on you.
This happened to me.
It was not lean after it was installed but become lean after I did a few WOT passes while adjusting my boost controller.
In any case, check your fuel pressure first before going on to anything else.
At idle with the vacuum hose connected to the FPR you should get about 34 psi and without vacuum you should get 43-45 psi.

[x2xtreme360]

Best thing is to post a log if possible.

However, start looking into the FPR and filter as possibilities. Think about adding a FP gauge to your setup.

[kjzstealth]

actually I am on the stock FPR still. I dont have any way of posting my logs. I put a cheap fuel filter on it before I replaced the pump, but I just bought a Mitsu one to try that.

Could the fuel pump overrunning the stock FPR be doing this? I thought that would make it go rich at idle.

[94PearlwhiteTT]

Are you running stock 9b's? What are you using for fuel management? Might want to check and make sure your settings on it are the same as they were when it was running good.

Also as stated, knowing what kind of FP your dealing with would help you out a lot.

[91STT]

check the voltage at the pump just in case to make sure that you are get sufficient voltage.
I know you have a hot wire set up, but check it anyway, you need to eliminate all possibilities.

[x2xtreme360]

actually I am on the stock FPR still. I dont have any way of posting my logs. I put a cheap fuel filter on it before I replaced the pump, but I just bought a Mitsu one to try that.

Could the fuel pump overrunning the stock FPR be doing this? I thought that would make it go rich at idle.

Overrunning the pump would make you rich, as you mentioned.

Stock FPR's fail all the time... it still could be the fpr.

[kjzstealth]

Are you running stock 9b's? What are you using for fuel management? Might want to check and make sure your settings on it are the same as they were when it was running good.

Also as stated, knowing what kind of FP your dealing with would help you out a lot.

Yes I am on 9b's. I have a set of 15g's but I want to get it running correctly before I install them. I am using an Apexi AFC Neo, and it is supposed to be the updated one to work correctly. Actually at first when it was running so good I had it set at 0 correction but now I have turned it up as high as 25% in the ~3k range to try to get the fuel there but it just isn't happening. BTW I also still have stock injectors

[elyria_boy]

Any update on this? I have similar problem.

[kjzstealth]

No, I have not had the funds to do much at the moment but I am going to try to get a FPR from a known running good car. I was going to just change my injectors but I found out one of my DSM 450''s was bad.. Was going to hook my logger up and find out which one but my batteries had gone dead and I couldn't find my USB to serial converter. Ugh!!! I have a new one on the way and I will probably buy a reman injector instead of waiting on someone to ship me a single.

As of now I am about fed up with it. I just want it to run right.

[Austin@STM]

Also look into the sensors the vac hose runs to from the FPR, those go bad sometimes to. If you already got rid of the make sure the vaccuum line isnt kinked or leaking at higher pressure.

[kjzstealth]

thanks, will check that too. I have done the vacuum reduction but I will double check my lines. I know they are still in place but I need to do a leak test anyway. It starts having problems as low as 5-7psi

[Mean Green]

Compression test.

[kjzstealth]

Just an update: It was my factory fuel pressure regulator that had failed. It ran great at idle and even low throttle but ran ~13.0:1 AFR under boost. Now it drops to 10,0-11.2:1 under boost.

As a side note, anyone know what a good AFR at WOT should be? My logger batteries died and I can not for the life of me find my serial adapter to reload MMCD on my Palm, so I am looking for a safe AFR to run until I can tune it better.

Thanks,
Kelly J.