Changing the fuel pump in my 94z this week, car has been stalling awkwardly and most people have said to replace it. I was wondering if anyone knows of a site with a few tips or if you have any tips of your own. thanks

 

It's a major sonofabitch to change. I would not do the job unless 100% sure that's the problem.

You'll have to either cut a huge access hole in the floorpan of your car to get to the pump, or, get the rear high in the are, drop the axle, remove exhaust, shielding, trim around filler neck and cuss/scream as you try to wiggle the tank out.

 

the idea was to get the rear high up and drop everything down.

for the assurance ill quote the post i made about the problem about a month ago

couple weeks ago my car stalled while i was stopped at a stoplight, kinda confused i started it up and went on my way. a day later i was on the highway and when i shifted into 5th gear, i pressed down on the gas and nothing happened, put the clutch down and tried again, when i came out the car shut off, started it back up and went on my way. i replaced the fuel filter and the problem seemed to stop for a few days. the problem came back and it got worse, i noticed that when it is about to stall the rpms go really low when idling, about 800, and my oil pressure drops too. Today was the worse, every time i let off the gas to stop my car, the car shut off, was a hell of a drive getting home. me and my stepfather seem to think its the fuel pump, or maybe a clog in the fuel lines, but i dont want to buy the parts and go into fixing it without knowing its the sure thing.
any thing will help, thanks

i posted that a while back, since then ive done a full tune up, was suggested by a friend and also was time for one(now that was a sob) and basically it still does the same thing it drives for 5-10 minutes and starts to stall as if its not getting any gas at all

 

You can buy a fuel pressure test gauge for probably $20-$30 from an autoparts store... It screws on to the schrader valve near the fuel pressure regulator on the back of the intake. If when your problem shows up the test gauge shows no fuel pressure, then you probably have a bad pump. The usually get weak instead of only working intermittently though. Might see if you can chase the wires, or even test the fuel pump relay, if that goes bad it could show up with those symptoms. It's a lot easier to replace too!

 

so you think that its more of a random thing it might not be the fuel pump? maybe tomorrow ill swing by the store and pick up the gauge

 

Heck, you can even "borrow" the guage from AutoZone, just have to leave a deposit.

And yes, pump failures are often intermittent. - JM.

 

now to find the schrader valve, where exactly is that at again?

 

Its right at the back of the intake, the cap on it should just barely be visible looking straight down the top of the intake, just the the left of the fuel pressure regulator that has a vac line on it.

If you drop the tank, you must be prepared to do something with your exhaust, like cut it off just before it goes over the axle, then reweld it back together. I let my rear hang from the Lower contrl arms, and used a cable to tie it up just before it pulled the brake lines off...you can remove a bolt on the brake line beside the DS rear tire and will let it pull a little further too, you'll need all the room you can get.

I put up a post not long ago about some tips on doing this that I observed when I did mine with some pics....search my screenname and fuel tank.

 

thanks for the info, i got the schrader valve and got the gauge hooked up, it was at 40psi with the car at the on position and when it was started up it dropped down to about 35-37psi at idle, not to sure what this means now i remember being told it was supposed to be around there. but if it is what do i do now, is the pump still good? if so anyone got any ideas for the next culprit, if not then looks like i have much fun awaiting me

 

actually it would probably be good to know what the psi is supposed to be at for sure

 

well according the the hayne's manual the pressure is where its at, but like i said what does this mean, is the pump still good? what else could it be

 

just took it out for a drive, felt nice i guess, was gone for about 10-15 minutes, got on it a little and it was running smooth.

maybe i should ask this, when i opened the hood this morning i noticed one of the 3 fuel lines, the one that wraps around to the left side wasnt plugged in, i put it back in today, maybe that made a difference? who knows

any thoughts?

 

Yes, with key on, engine off, the pump will energize for a few seconds and pressurize the system to around 40-43# because there is no vacuum on the regulator. Start the car and vacuum in the regulator will pull the pressure down depending on how much vac the motor creates, usually 7-8 lbs is normal. Pull the vac hose off the regulator and you'll see it go back to 40-43#....gives you more pressure when at WOT.

Ok, one of the 3 lines..hmm, hopefully that was the vac line going back to the carbon canister...any others unplugged would cause massive gas spillage and fire. If the vac line was unplugged that would cause a vac leak and poor running. Sounds like you had described the problem as intermittent....if so, you need to be able to see the guage when it starts acting up. The line being unplugged would cause a problem when the solenoid for it is engaged so that might explain the intermittent part, but it would have been anytime you hit the right rpms/load/etc to cause the vacuum to be applied to the canister..

Keep driving it and see if it arises again.

 

yea it was the vac line. when i let the car sit for about a week i can usually go a day without it stalling, but then the day after it will start giving me **** again. its not really at certain rpms when it starts to stall, most of the time is when i am stopped or stopping, its also happened at about 3000 rpms riding on the street, and on the highway

 

well like i suspected it stalled again today, to bad it wasnt that easy