MTBSully

iTrader: (7)

Got a fuel pressure tester a few days ago and for the past three days i have been working on my car. Here are the results:

Priming the pump, i get about 15psi, which bleeds off as soon as the pump shuts off.

With the car running, i get about 23psi, and removing the vac hose of the regulator has no effect on pressure. I even tried increasing the fuel pressure with my holley AFPR, but it never changes.

So today, i swapped my stock regulator back in. Still about 15psi on a prime, and about 23psi while running. Removing vac line has no effect. While i had the fuel rails pulled up, i had my brother prime the pump a few times while i watched the injectors. It would appear that none of them are leaking. Fuel filter is new as of yesterday.

Whats going on here guys. Does this sound like my fuel pump? Check valve maybe?

ElkySS

iTrader: (6)

sounds like a pump 2 me

sz282

iTrader: (5)

Yeah seems like you need a new pump.

96capricemgr

iTrader: (1)

Some fuel pumps come with a black rubber stub hose for in the tank, and they do not last, when they split the symtoms are similar to what you are seeing.

SLawson86

iTrader: (8)

does the car run? if so, does it run pretty good? could be possible pump, but on an LT1 Fbody i doubt it is the stub hose. reason being it is a disconnect style accordian hose. i would really suspect the gauge is faulty if the car runs pretty good. but about the bleeding off, if it is an aftermarket such as a walbro they dont hold residual pressure. the stocker should

t-rocks firehawk

im not sure but my 94 runs between 40-50 pounds

96capricemgr

iTrader: (1)

Like I said some fuel pumps come with, as in replacements not original, seen it happen on LT1s when folks cheap out and don't buy something good like the Racetronixs stuff.

RoAdRaGe912

It happens to the best of us...

I had one split on me after two weeks, and had a second cheapo (free replacement) split again while I was waiting on a good one to show up in the mail.

LM97Z

iTrader: (4)

Agreed, thats what happen with mine, those rubber EFI hoses do not hold up submerged in fuel, you either need a steel braided hose, or the plastic straw style.

MTBSully

iTrader: (7)

well i was told an aftermarket pump was put in there recently. Car runs pretty well, but reaaly bucks and stumbles and almost dies when your getting it going in first gear. Also i don't think the guage is faulty. I tested my expedition and it had 42psi when primed, and 33 or so with the vac attatched.


so what fuel pump should i go for? Walbro 255? Anything else i need? Looks like im cutting a hole in the back of my car soon.

RoAdRaGe912

You should have read past the first two posts.

This should be the next thing on your list to check, especially since you think it recently had a pump installed.

MTBSully

iTrader: (7)

I did read all of the posts. Either way, you guys are telling me that i need to pull my fuel pump to check things out.

ElkySS

iTrader: (6)

i cut my hatch to get to my fuel pump. best thing i ever did. takes me one hour, start to finish to replace a fuel pump. check out this site. it shows you exactly where to cut.

http://www.taekwondoplus.org/z28/fuelpump.html

LM97Z

iTrader: (4)

This statement doesn't make any sence

Ok, now that i'm through being a smart azz , i would cut the access door, its not hard too do, & makes for changing pumps a breeze, if the pumps been changed recently, i'll bet they used a rubber hose, what i did with mine was used a steel braided & clamped them on both sides, its holding up very well, the pump i went with was a Walbro 255 from EPP, so far, so good, it was like 100.00 bucks.

MTBSully

iTrader: (7)

okay your right. I guess what i meant to say is that it idles and revs well, but bucks and stumbles really bad when your trying to get moving.

Im going to cut the trap door either way. Mainly because i want to check things out. Also, who is ever going to see it when its covered by sound deadening material and carpet right? Thanks for the links guys.

Do you have any pictures of what you did? im not sure where or what rubber hose you are talking about. Ive never had to do a fuel pump before.

LM97Z

iTrader: (4)

Its the main feed line in the pump assembly, you'll see it when you remove the pump (assembly) from the tank, i'm sure yours is like mine (being a 97), the factory feed line is a plastic "straw" style, maybe someone has pix for you they can post.

MTBSully

iTrader: (7)

oh okay that makes sense. so i guess tomorrow im going to make the trap door and check things out. maybe see if the previous owner put a rubber hose in there and it cracked or something. If not, i'll be ready to put in a new pump.

Anything else i should look for? Thanks guys

MTBSully

iTrader: (7)

what would you guys recommend for making the cuts? A dremel with a cutoff wheel or maybe something bigger? Thanks guys

RoAdRaGe912

Dremel will take forever. I started mine with a dremel, made the major cuts with tin snips, and then cleaned it up with the dremel.

Formula350

iTrader: (3)

It's sparky, but if you have any flame retardant material around or some old clothing you don't care about, you could drape it over the interior and carpet. Then use a air cutoff wheel. An electric one would work too (angle grinder with cutting disc). Would just leave a cleaner cut compared to a tin snips, probably not be so hard on the hands either heh.

If I ever do a trap door, I plan to put a hinge on it and some form of latch, just an idea for ya.