Hey guys. Ive had this fresh setup in my car for less than 5K now, and tonight out of the blue for the second time I had to mess with/adjust the fuel pressure because the car was going lean.

The first time it was going lean across the board, idle, cruise, boost. And to fix it I pulled off the stock FPR and put on a used B&M adjustable unit I had and set it to 42psi with the line connected and that put my tune back to perfect.

Tonight I was doing a highway pull and noticed the AFR's were 12.9-13:1, but cruise and idle seemed unaffected while I watched the rest of the way home, boosting slightly a few times to see if it continued to run lean.

Sure enough when I get home I pop the hood and the fuel pressure gauge that is mounted on the RAIL shows 37-38psi. Adjust it up to 42psi and the pulls are clean again.... the lock nut on the FPR was still tight to, it didnt just rattle a quarter turn loose.

I do have a walbro 255lph, which is VERY whiny, especially right now. Sometime its quiet, sometimes its quite loud and noticeable even on the outside of the car.

Where would you guys go with this? Should I just drop the $100 on a new fuel pump? Possibly another issue at hand here?

 

Those FPRs are garbage, get a real one or replace it with a known working stock one.

 

Aeromotive A1000 regulator. Spend the money and you wont regret it.

My 255 always seemed a bit loud after a long drive

 

Even the stock factory FPR was what gave me the first lean condition, and it was on the car for a year n/a with no problems. As soon as I boosted, Ive had this problem twice already!!

Thats why I was thinking it could possibly be pointing to something else

 

If your fuel pressure is dropping and your pump is screaming it could be a restriction. When is the last time you replaced the filter.

 

It could be a wiring issue also. You could try wiring in a relay with some 12 gauge wire to get the pump a good power source

 

Def do this. Even if it doesn't fix your fuel pressure issue.

Just curious but when you set your fuel pressure did you do it cold or hot? I didn't have much of an issue when I had the stock FPR but I've noticed my fuel pressure drops as the car warms up with my aftermarket FPR.

I do agree about getting rid of the B&M regulator.

 

The fuel filter was swapped out with a generic autozone piece when I got the car, about 8K miles ago. Pretty fresh

I set pressure with the car hot, just checked it again and adjusted it up slightly as the car was slightly leaning out again on the way home....

Not sure what the heck is going on

 

Take off the vac line going to the regulator and blow on it. If you have a compressor maybe hit it with 15 psi or so. See if you happen to have a small vac leak on it. It could be small enough you don't hear it with the engine running.

 

The vac line is new, but I can try that. Im assuming you mean with the car off and FPR still atached to the car

 

Yeah. My fpr has a threaded vac fitting but the B&M is one piece, I believe. I was just wondering if the regulator itself has a vac leak. I'm sure nothing will come of it, but it is simple to do, quick, and a way to check off a box.

 

The B&M also has a threaded vac line, thats how you adjust it, loosen its locknut and turn the vac nipple in or out. The body is also 2 piece bolted together

 

Ah, mine has a separate threaded vac port on side and is adjusted with allen stud on top secured by a jam nut.

I would still try checking for a leak, do it when warm. I wonder if the regulator is warming up and expanding at different rate from the vac fitting.

 

No leak

 

What fuel is being run just pump gas or ethanol e85 ? If E85 i would say is the filter comign apart. Otherwise pull the line off the filter and check that the pump is flowing well and not whining when free flowing. If still whining pump could be clogged or bad.

Did you put the B&M hack on the regulator that failed you to begin with ? Thats reuses the internals of the OE Regulator and that would def be a problem even with the B&M piece on there. get another known good regulator and see what happens. Also can put the b&m on a new regulator OR just get an aeromotive 13115 or 13116.

 

Try this. With the car idling slowly pinch the return line after the reg closed. Pressure should spike. If that happens it suggests your pump is ok. Of course under load is a different thing, but building pressure will strain the pump.

 

Just regular pump gas

What do you mean after the reg closed? I did pinch the return line with the car idling and the pressure does spike and hold the more and more I pinch it

I can try and get an FPR from the wreckers tomorrow, but will probably have to retune as I tuned the car after putting on the B&M and setting it to 42psi, the stock FPR was like 34psi

 

You did what I was asking. That is what should happen. If you go with a different adjustable regulator I would stay away from the aeromotive 13115 or 13116. I had one and it started pissing fuel everywhere after a few months. I got no help from aeromotive on it. That was at 9-10 psi.

 

Chances are I will just pick up a stock FPR from the yard if I can find one.

But im not quite sure that is even my route, if I have good fuel pressure, what else would cause a change in boost AFR's when they were solid since last tuned

Trying to avoid just shotgunning parts

 

I didn't see if you answered about the fuel pump relay. It has to be an issue with one of the FPR, Pump, or injectors (since you said filter has been replaced). How old is pump? The other thing could be something electrical. For instance the main relay. Mine failed recently but before it failed it would occasionally cause me to run lean momentarily during cruise.

What EMS are you using? Can you data log voltage?

 

Stock Crx wiring, didnt see it being a problem for 250whp.

The walbro fuel pump is a fuel years old, had it on my last setup aswell

Injectors are prescision 680s and 5k old aswell

And no turboedit does not let me monitor voltage at the pump or anything

 

This is a long shot but first I would check voltage at battery, before you start it and then once it is running. Also check it after it is warmed up. Also check voltage coming from the alternator (both after start up and then after it is warmed up).

I would also try wiring in the relay. It could be the pump needs a little more voltage as it wears.

 

How old is the fuel pump sock?

 

Voltage is steady @ 14.3 with the car running at both the battery and the alt

Fuel pump sock is OEM, 80k miles, reused the factory one when I put in the Walbro

 

Id really love to keep the stock wiring to retain reliability as this is my DD

I think i may pull the trigger on a new pump and just try it. The car is still leaning out in boost even with the bumped fuel pressure