92 brew fuel pressure?

[rnj]

Can a car run with just 3-4lb s of pressure???car starts, but surges and runs like crap.

[HotZ28]

Originally Posted by rnj

Can a car run with just 3-4lb s of pressure???

Nope, it may start, but will "surge and runs like crap"!

[rnj]

tks, had a fp put in(supposedly), ran better, but not normal. then started bucking/surging.

[HotZ28]

This sounds like the fuel pressure regulator! How long has it been since you changed the fuel filter? What is the fuel pressure with the new pump installed?

[rnj]

Not sure on fuel pressure. the fpr is in the throttle body. I took it apart, and diaphram was still good. So I figured it was o.k. How can you tell if the fpr is bad on tbi.

[HotZ28]

IIRC, the TBI system should operate between 12-15 psig. It’s hard to see a leaking diaphragm, they usually leak under the metal spring retainer in the center of the diaphragm. You can buy a FPR for the TBI for about 30 bucks at Advanced or, you can purchase a TBI fuel pressure test kit for 69 bucks. Click Here
If it were me, I would replace the FPR first.

[rnj]

if the fpr was leaking, would I see it dripping, or will it be a small leak. if it is a small leak does that affect the idle alot or a little.

[HotZ28]

The last FPR I installed in a TBI system, you could not “see a leak”, or see excessive fuel passing through the injectors. The diaphragm looked perfect to the naked eye, but the engine would buck, stall and hesitate above 2500 rpm and sometimes shut off at idle. In fact, once I removed the FPR everything looked so good; I wondered if I was replacing a perfectly good part. After I replaced the FPR, it ran like a champ. I cannot guarantee that this is your problem, however, your description of the symptoms point in that direction!

The FPR has vacuum on one side of the diaphragm and fuel on the other. These two components do not like leaks of any type, between each other. If the diaphragm is leaking, you will have low fuel pressure and more than likely suck raw fuel through the vacuum line. When you accelerate, vacuum drops and the fuel pressure will prevail.

[rdmaster92]

Have you had a chance to do the regulator yet, and did it help?

I was just going through some documents I have scanned into my computer, and ran across one I did after I replaced my pump a couple of years ago, and I remembered this post. Pressure on the old pump was 7psi. New pump was 14psi. The wire harnass tag was BAK 50 (though yours may be different). Actually, I remember the tag was an important distinction when getting the new pump. I also wrote down part numbers on the pumps, tank, and tank straps.