2000 Oldsmobile Alero fuel pump

Tiny
OMCL1004
  • MEMBER
  • 2000 OLDSMOBILE ALERO
  • 157,000 MILES
Replaced fuel pump on car 3 years when I first bought it and has ran well till today. Wasnt getting gas.I automatically assumed fuel pump. I swapped ac and headlight relays to fuel pump and still nothing. Bought new fuel pump and installed and still nothing. Removed fuel pump and hooked mstraight to battery for a second and it runs fine. Checked for power with on grey wire at fuel pump in on posistion and no power. Checked again while cranking and there was power about 2 times out of maybe 5 attempts. Mp wiring harness with ke
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Sunday, August 18th, 2013 AT 1:39 AM

16 Replies

Tiny
WRENCHTECH
  • EXPERT
You should have power on the gray wire during the first 2 seconds of "key on" and whenever cranking. If the signal is intermittent, try unplugging the oil pressure sender and check it again.
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Sunday, August 18th, 2013 AT 4:26 AM
Tiny
OMCL1004
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Okay thanks. Ill try that. Exactly where is that on my car?
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Sunday, August 18th, 2013 AT 4:44 AM
Tiny
WRENCHTECH
  • EXPERT
Probably near the oil filter.
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Sunday, August 18th, 2013 AT 4:50 AM
Tiny
OMCL1004
  • MEMBER
Hi, I unplugged the oil pressure switch and still no power to fp. I jumpered pins 30 to 87 on fp rekay and no power to grey wire still. Im stumped. Btw, I checked each of the 4 fuel pump relay terminals and each one shows hot when grounded to body?
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Monday, August 19th, 2013 AT 8:03 AM
Tiny
WRENCHTECH
  • EXPERT
Do you have power at pin 87?
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Monday, August 19th, 2013 AT 9:30 AM
Tiny
OMCL1004
  • MEMBER
Yes, with key on
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Tuesday, August 20th, 2013 AT 5:05 AM
Tiny
WRENCHTECH
  • EXPERT
Pin 30 is the gray wire so if you are supplying power to it and it's not reaching the back of the car, that wire has to be broken somewhere.
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Tuesday, August 20th, 2013 AT 5:39 AM
Tiny
OMCL1004
  • MEMBER
Thanksfor bearing with me on this. So, if I cant find where the wire is broken, is it possible that I can add a wire with a fuse inline to a wire thats hot with the key on? I think I read that the comkputoer supplies the ground. Am I right?
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Wednesday, August 21st, 2013 AT 8:10 AM
Tiny
WRENCHTECH
  • EXPERT
No, you find out where the gray wire is damaged and repair it.
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Wednesday, August 21st, 2013 AT 8:24 AM
Tiny
OMCL1004
  • MEMBER
Hi, The grey wire shows continuity from the fuel pump all the way up to the fuse box on the drivers side dashboard. To be clear, the #30 pin on the relay fuse shows hot when grounded to frame, however, all the other 3 show hot as well. Is that the way it should be? I was told if I jumper #30 and #87 and if the fuel pump works, then the computer is bad. Well, when I jumper the 2 it does not work grey wire not hot so I'm assuming the computer is good. Does the gray wire go through the computer or just the ground wire? I assume the #87 pin must be ground, but then why is it hot when tested with the meter? Unless the computer switches it to ground some how?
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Wednesday, August 21st, 2013 AT 7:16 PM
Tiny
WRENCHTECH
  • EXPERT
Don't listen to that guy. Your computer is not suspect here and that advice was a load of crap.

Something is drastically wrong with your testing.
You said you had power on pin 87.
Pin 30 is connected to the gray wire and a straight shot from there to the pump.
You said you connected Pin 87 to 30 and had no power at the pump, yet you tell me the gray wire has continuity.

That's just not true.
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Wednesday, August 21st, 2013 AT 7:22 PM
Tiny
OMCL1004
  • MEMBER
Yes thats true, at least what I mean by continuity is that I knicked the gray wire under the back seat and knicked it coming out of the fuse box on the drivers side dashboard and put alligator clips on both bare wires and the ohm meter needle jumped. Isn't that how to test it? And yes, like I said, all 4 pins show 12 volts when I turn on the key. Are they supposed to? If so, then grey wire must be broke or burnt somewhere under the dash between the fuse box under the hood and the one on side of the dash. I am baffled because, being all 4 of those pins shows to be hot, then when I jumpered them, I would think they wouldve sparked, got hot etc, but nothing happened at all.
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Wednesday, August 21st, 2013 AT 8:52 PM
Tiny
OMCL1004
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Hi Wrenchtech, Please accept my sincerest apology for being so damn stupid! I never once intended to undermine your expertise nor to insult your intelligence. I'm the one who is dumb! The whole time I was using the positive cable on the fuse block as a body ground, (explains why the 4 pins were all hot) I only realized it was hot after researching for 3 days on how to remove the fuse box from the car and the 1st thing it said was to remove the positive cable from side of fuse box! Oh well, live and learn, huh? I know now why you stopped replying to me. You must thought I was a total idiot! Anyways, here's where I'm at now, if you will continue to help this idiot. I pressed the tab on the bottom of the fuse box and it sprung forward naturally due to the pressure of all the cables going into the back of it. So, I stopped there and checked for power and it did show just a bit of power. (I've ran my battery almost completely down though so can't really test anymore till recharging it tomorrow) I know this will sound like a dumb question to you, but how can I tell which pin is #30 and #87? I think the relay will work any way you put it in won't it? I never really paid any attention to that, but one way would have #30 in upper right corner and the other way would have #87 up there. It seems like the one I detected a little power on was #87, which was lower left, and you said #30 should be hot I think. So, when looking at the fuse box from the drivers side fender, which would be which? I plan to take it apart tomorrow and look for loose wires and clean it up a bit maybe. Any advice?
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Thursday, August 22nd, 2013 AT 11:58 PM
Tiny
WRENCHTECH
  • EXPERT
Yes, the pins are at diagonal corners so the relay can go either way. Pin 30 is the pump, 87 is the power supply.
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Friday, August 23rd, 2013 AT 7:20 AM
Tiny
OMCL1004
  • MEMBER
Thank You for sticking with me! Ok, I removed the fuse box under the hood and took it apart and found no broken, burned or loose wires. There was a little corrosion around a few of the spades which I cleaned up and then put it all back together. The sockets that bolt on were a bit loose (easily turned with socket) so I tightened them down good. Now, when I jump #30 and #87 the fuel pump does come on and stay on as long as the key is in on position, but it won't start though. Almost started for a few seconds then died. Is that what it should do when jumped like that or should it run that way? Also, I've figured out that pin #86 is ground and that leaves pin #85 which shows no ground or power. Does the computer control that wire or the ignition switch? Btw, I was checking it by myself by disconnecting negative battery cable and leaving key on and then touching the cable to battery momentarily and at one point the ABS relay started clicking and then the fuel pump relay started clicking so I left it hooked up and tried starting it and the relay quit clicking again and it would not start. Charging battery again right now to try other suggestions you may have. Do you think I should perform the reset procedure after all the messing around with it that I've done? The security light isn't blinking.
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Friday, August 23rd, 2013 AT 10:32 AM
Tiny
WRENCHTECH
  • EXPERT
So, after 2 pages of back and forth you have absolutely no idea why it won't start or whether the fuel pump has anything at all to do with anything.

Now you start from scratch.

Perform every one of these tests before you do another thing.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Friday, August 23rd, 2013 AT 11:21 AM

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