Chevy Impala SS Forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #1 ·
Hey guys,

I know that I mostly post in the MISK, but I've got a real problem on my hands that I can't seem to fix.

I've got a 95 wagon. I DROVE the car to where it sits and it ran fine. I recently swapped rear ends in the car, and when the ass was up and the nose wasn't - I hit the key to start the car. It started but immediately died. I could give it throttle and it would sputter a bit, but then die within seconds.

Figuring it may just be low on fuel, I poured in 5 gallons of gas, and it didn't help.

I then jacked up the front of the car to level it out, which also didn't help. It started long enough for me to run to the front of the engine and give it huffs of carb cleaner, and only stayed running as long as I keep doing that.

I then checked the fuel pressure and it was low and inconsistant. It was about 32 at startup, then bobbled around the 20's depending on how much throttle I was giving it.

So I just finished installing a new fuel filter on the rail and a new fuel pump with sock inside the tank. I was SURE this was it, but as soon as I hit the key - it only started long enough to die again - and it still only stays running if I let it huff carb cleaner.

I'm going to change fuel rails tomorrow with one that I'm sure is good - which will give me a different fuel pressure regulator, but I'm not sure that's going to help either.

So for real, if the car DRIVES to a spot then quits running - and you know it's got to be fuel related - and you install a new pump and filters - what the hell else COULD it be?

I need this car back on the road ASAP - so any and all help is greatly appreciated.

Thanks in advance,
John
 

·
Registered
Joined
·
9,682 Posts
How did the wiring look inside the tank? You probably know already, but these cars have a history of melting connectors at the bulkhead where it plugs in at. If you didn't check the wiring or change it, that's where I'd look for a problem.


Don't bother with the fuel rail or regulator, neither are likely the problem. I wish you were a little closer, I'd stop by and try and give you a hand (no ****). I'm too lazy to drive out there. But feel free to call me though and I'll see if I can help ya over the phone.
 

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #3 ·
All wires in the tank looked like new. I worked in the fuel handling design group at Delphi for 5 years, so I've seen lots of failed wiring - and the wires in there looked great. Very flexible and ZERO discoloration. I can't imagine how in the world that'd be it.
 

·
Registered
Joined
·
576 Posts
"I then checked the fuel pressure and it was low and inconsistant. It was about 32 at startup, then bobbled around the 20's depending on how much throttle I was giving it."

Its amazing how/when stuff will fail.

Your comment above, especially the inconsistancy of the fuel pressure points to classic FPR problems.

I just replaced mine chasing an unrelated problem in hopes that it would be the cure [NOT!]. I'd hate to bet on anything with these cars.

Good Luck!
 

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #6 ·
Thanks G. Hopefully that'll be it, but I've had others swear it couldn't possibly be the FPR. At this point in the game - I'm changing it anyway with one from my parts car and hoping for the best.

Either way, I needed to ask so that I know what else I can try if the FPR isn't it.
 

·
Registered
Joined
·
576 Posts
Unless that rear harness plug isn't seated properly? I've went through and re-checked every plug in connector on mine and applied dielectric grease just to be sure.

Good Luck tomorrow :)
 

·
Registered
Joined
·
1,233 Posts
Thanks G. Hopefully that'll be it, but I've had others swear it couldn't possibly be the FPR. At this point in the game - I'm changing it anyway with one from my parts car and hoping for the best.

Either way, I needed to ask so that I know what else I can try if the FPR isn't it.
With ignition ON, pull the vacuum line off the FPR. There should NOT be any fuel in the line or dripping from the nipple of the FPR.
 

·
Registered
Joined
·
4,810 Posts
You could try to check the fuel system without the car running by jumping the fuel pump test port. It's the little red wire near the A/C drier that is disconnected. Just put +12v to the plug, and that will run the pump. Verify that the pressure is correct and steady for a good period of time. You could then try to start the car, if it doesn't run, then perhaps, long shot, it's the stupid pass key.
 

·
Premium Member
Joined
·
15,727 Posts
Why is this fuel pressure problem not likely to be the fuel pressure regulator? I don't really get why everybody would dismiss that. Also, consider whether you may have gotten some junk in the fuel line between the pump and the new filter. Just a thought.
 

·
Registered
Joined
·
576 Posts
Why is this fuel pressure problem not likely to be the fuel pressure regulator? I don't really get why everybody would dismiss that. Also, consider whether you may have gotten some junk in the fuel line between the pump and the new filter. Just a thought.
Not everybody :)
 

·
Registered
Joined
·
701 Posts
Did you check the external wiring? The connector is behind the bumper on the drivers side, it might have gotten snagged while working in that area. Also check the wire connection inside the wagon. Remove the drivers side storage compartment and check the connections back there. The bundle with the fuel pump wiring has purple wires going through it. Worth a shot.
 

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #16 ·
Well I ran a hot lead to the FP hotwire spot and it ran great. It ran, idled, revved, the whole 9. Then I unhooked it and a couple minutes later, it ran great again without it. Then a few minutes after that it was back to dying - but per usual, I could kinda rev it in short bursts.

So a wagon guy suggestion that seems legit is that it's probably a "wonky oil pressure switch" - that lets the car start - but then kills it as soon as pressure doesn't register right.

I checked the oil and it's on the money, so I'll be changing that switch out real soon.

Thanks,
Chachi :)
 

·
Premium Member
Joined
·
2,327 Posts
Well I ran a hot lead to the FP hotwire spot and it ran great. It ran, idled, revved, the whole 9. Then I unhooked it and a couple minutes later, it ran great again without it. Then a few minutes after that it was back to dying - but per usual, I could kinda rev it in short bursts.

So a wagon guy suggestion that seems legit is that it's probably a "wonky oil pressure switch" - that lets the car start - but then kills it as soon as pressure doesn't register right.

I checked the oil and it's on the money, so I'll be changing that switch out real soon.

Thanks,
Chachi :)
After I swapped the motor on my 94 cap wagon I was having the same thing and thought the oil switch as well. Then I remembered the pcm does not care about the oil switch. After checking voltage and looking under the hood for a few I noticed I forgot to hook up all the grounds at the coil (which I thinks runs to the FP relay) and that was my problem. So check your grounds and the FP relay.

HTH
 

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #18 ·
Well, between buying new parts and with having a parts car here to borrow parts from - so far I've replaced:

NEW:
Fuel Filter
Fuel Pump

SWAPPED IN:
Fuel Rail including Fuel Pressure Regulator
PCM
Oil Pressure Switch
Fuel Pump Relay

I also removed the drives side cargo area and inspected the ground wire there - and the whole thing looked MINT. There was no indications of trauma or drama.

And again, the only time it's run the way it's supposed to is when I've ran a hot wire from the battery to the GM supplied fuel pump hotwire wire. When doing this - it idled great, I could rap it up, I held it at like 3000rpm for about 5 seconds, it returned to idle when I let off the gas, sustained idle for about 10 more seconds, and I revved it a few more times, then shut it off.

Maybe I'm off my rocker, but with it running great with a different ELECTRICAL input indicates to me that it's not a "mechanical" problem, like a leaky tube, or pressure loss, or a bad mechanical part. It also tells me that my assessment of the ground wire at the back of the car is also good.

I'm about "-->this<--" close to finding a wire that's hot with the friggin key on and running it to the hotwire spot, and getting on with fixing the OTHER problems with the car that require it to be running.

Seriously, how can all of THOSE parts be good, and the damn thing STILL won't stay running. Like I said, it starts, then wants to die unless I repeatedly blip the throttle - but even then it only lets me blip it so many times until death catches up to it.

Thanks too Klez, but wouldn't it running great when using the alternate HOT input also verify that my current grounds are legit?
 

·
Premium Member
Joined
·
15,727 Posts
What does that hot lead bypass in the rest of the wiring that get's used when the car's running?
 

·
Registered
Joined
·
8,941 Posts
Discussion Starter · #20 ·
Don't really know, but when it went from working to NOT working - I figured that there must be a mechanical issue that had to be resolved before we could return to our regularly scheduled brokenness.
 
1 - 20 of 25 Posts
Top