Well, my car is screwed up. I think either the fuel pump is going, or the ECM isnt tellin it to energise on start up. Has to be one of these to, as I've replaced the relay, and tested all the wires for conductivity. All good. But problem consist. (fuel pump wont energise the vast majority(80-90%) of start-up attempts).
What do you all think is more likely? Fuel pump screwed or ECM fried? I think ECM, because the relay doesnt always reset. Could anyone provide very specific details as to the operation of our fuel pump relay? I also have a code 54 (low fuel pump voltage). I think fuel pump *could* be going, but I think ECM may also be to blame... Is there any way to get a ECM for cheaper than AutoZone (95+ 150 core deposit)? I kinda wanna hook a good ECM up, and see if that helps....

 

I'm saying its more the fuel pump than ecm.

How this works as I recall is that you put it in the ignition on position the system gets primed for 2 seconds. You can only prime it once per 15 seconds. So you must wait. If it doesn't prime consistently at those 15 second intervals, then I'd start blaming ecm.

Fuel pumps are notorious for dying simply due to hard cornering. The pump gets starved, it overheats and eventually fails. There were a lot of efi cars back in the mid-80's who had relatively low mielage and bad fuel pumps so gm started installing baffles stock in something like 91 as standard.

A fuel pump change is not an easy job. I wouldn't recommend you do this yourself unless you have help.

 

I was *hoping* it wasnt the fuel pump. But appearently, it probably is....
Oh well. I do have help. Me and my dad would be working on this. Now, does anybpdy have drawings (like out of a shop manual or something) of the tank assembly and how the pump is in there and all that good stuff? Also, with 2 people, how many hours am I looking at?

 

yea that sucks fuel pumps are no fun...local shop wants 250.00 plus parts to do mine...

i have a 86 5.0 tpi

but i have a question hard start just in the morning when car sits a long time starts as long as i tit the throdel 1 time while cranking...checked tps .56 idel 4.03 at wot other thing i did was pus pressure gauge on and at prime i have 40 psi shortly after it bleeds down to 22 psi then 2 hrs later i checked i am down to 12 psi bad pump??????

 

My old pump died on me during a coolant change in the driveway...

I'll give you as best an accurate account of my experience.

Car had to be lifted high, we're taking high enough to drop the axle that the springs would pop out. Watch the brake lines ensure you have enough slack. Once that was accomplished you have to get the muffler out of the way. Easy for bolts, hard for welded... I found out welded is bad...

Once that was done, get the muffler shield out of the way then unbolt the straps on the tank, mine were rusted PITA. Once that's done you should have the tank easily accessible to the point you can pull it out. Careful it comes out at a weird angle due to filler neck and you need 2 people to do this or your noggin will feel some pain.

The pump comes out quite easily. Its not that hard to figure out how to remove the pump, twist seal use screwdriver to pry, if careful can keep original seals. Remember to replace the strainer too while you're at it. It took a good 5 hours to do plus driving sans muffler to shop for a reweld.

Make sure its not the relay that is dying, you can do this simply by listening for the relay click when priming. Be 100% sure before you do this. I had a 12 v feed to a fan switch which I hooked up to my fuel pump and kept trying to activate the pump to make sure the pump was dying/dead before I undertook this task. If I would do it again, I'd have it sent to a shop.

 

Local shops charge 350. I dont got 350. Anyways, my relay isnt dieing (just put new one it - didnt change problem). Although it dont clikc everytime. Wierd?