View Full Version : fuel pump or elect. short? '92 Bonne.
02-20-2006, 03:25:14 PM
A couple of issues have come up with my '92 Bonneville.
The most pressing is that it will only run for a few minutes before it dies. I thought it was an extension of an electrical issue that was causing a need for recharging the battery every week. The symptom was the whole dash would blink and dim. These are very electrically demanding vehicles. I replaced the battery and tested the alternator. The alternator is good. After that it started shutting off after less than 15 minutes of driving. When I shut everything off and then turn the key back on, sometimes you can't hear the fuel pump running anymore. Try the key and it turns over, sounding like it is out of fuel. When you can hear the pump it will restart. The more times it does this, the longer the car will go without starting and the shorter the time it will run before dieing again. Is this an overheating, failing fuel pump?
The second issue, which may be effecting the first, has two symptoms. When I put the car in reverse, the front courtesy lights come on, even when they are switched off. And the coolant temperature gauge registers low when the fuel tank is full, and continues to register higher and higher, upto danger warning levels, as the fuel tank level drops during driving. As soon as you refill the tank the temp guage drops to lower levels.
So, can anyone help me with this electrical gremlin?
How about some pointers on testing, not guessing, on the fuel pump?
187k miles on the car.
Need any other details?
02-20-2006, 03:53:07 PM
You can get noid lights and test the injectors - To test the fuel pump (as my hazy recollection of this college course goes) you'll have to find the amount it ought to push and run it into a bucket for a timed amount of time..... I think. : \
02-20-2006, 07:12:22 PM
I was thinking more along the lines of how and where, and how and where NOT, to test the fuel pump for receiving electrical power. When the car shuts off, how do I find out if the pump stopped getting electricity, or is it still getting current, but stopped anyway? Wouldn't that tell me if the pump was perhaps over heating?
02-21-2006, 08:41:25 PM
the pump should be in the tank. there should be a wire or two going to it. you are going to need to check them for current. the pump will not overheat because it is kept cool by the fuel. but, before i did all of that. i would be looking for a loose ground wire.
02-22-2006, 01:56:56 PM
I replaced the fuel filter this morning. That certainly improved the situation, but did not correct it completely. Once the filter was changed, I started the car and let it idle for 30 minutes. No problems, at all. It would not do this before. It would have died after about 10 minutes. I thought it was all fixed. Then I tried to back it out of the driveway, which has a bit of an angled drop at the end. As soon as I stopped at the end to check traffic, it died. Then it didn't want to start again. I towed back up the drive, closer to level and let it sit. When I tried it again, backing up and hitting the breaks hard, it died again. But it restarted, a little bit hesitantly, and went forward and back a couple of times each, with no problem. The tank is 3/4 to 7/8 full of fuel. It is also 10 to 15 deg F warmer today, than it was the day it died and became problematic. I still have the electrical gremlin in the courtesy lights.
Could it be debris in the line? Water? Should I run some Stabil or injector cleaner through it? Is it still likely to be the pump, not overheating, but brushes and windings wearing out? Help, I could really use two vehicles this weekend and I'm running out of time and options. Clearly, a dealership or other expensive choice is not an option.
02-22-2006, 02:10:20 PM
Sounds like the pump may be starting to pack it's bags for vacation.
02-22-2006, 04:11:45 PM
I took it for a test drive. The drive lasted about 15 minutes before the car died again. I waited about 5 minutes and it restarted. That lasted about 1/8 of a mile. This time it took almost exactly 1 hour before the car would start again.
02-22-2006, 04:13:42 PM
Well, if it is a pump, at leastit isn't too expensive for that car.
02-22-2006, 04:33:54 PM
This is one of those few setups where the the fuel pump is not a "fully assembly only" item. I checked prices, Autozone doesn't carry it. AutoPartsWarehouse.com lists it as $112, plus $20 for the siphon tube screen. I'm not sure on shipping. The challenge is going to be getting it up high enough to get the tank out from under the car.
02-22-2006, 04:36:17 PM
Good luck getting the tank out, I had fun in my third gen doing that. It also sounds like the same pump setup.
Have you checked at Advance Auto Parts?
02-22-2006, 05:08:53 PM
Check the fuel pressure regulator.
Even with a good pump, a bad pressure regulator may be your problem.
02-22-2006, 05:16:34 PM
How do I determine if it is the fuel pressure regulator? This is a $55, special order, wait 3 days item.
On the plus side, I do have the factory service manuals for the car. Though these tend to be remove, replace, and somewhat assumptive of the readers knowledge level. I guess it's time to go back through it an figure out what wires to poke to test for power to the pump when it stops pumping. Then hope I can find the electrical gremlin.
03-08-2006, 05:25:23 PM
I finally have a new fuel pump installed. I have to wait until later tonight to take it for a test drive and hope that the problem is now fixed.
If you have a car with an electric fuel pump that lives inside the fuel tank, you would benefit from an access hatch above it. I'm just sayin'.
03-09-2006, 12:03:54 PM
Test drive went without a hitch. So, it seem it was the fuel pump dieing slowly.
03-09-2006, 06:08:10 PM
No, apparently it was NOT the fuel pump. Every step has made the car drive longer before failing. New battery, new fuel filter, new fuel pump relay, new fuel pump. But the problem is still there. It dies - inexplicably. Then at some random time, it might restart.
I need some serious electrical guru, grounding issue, help. Please.
03-10-2006, 04:09:05 PM
Can you get to the wires close to the fuel pump to make a temporary connection into them to allow a 12V light to be wired up to it ? (this would give more of a visual indication of power/who care how the wires are run right now and if you want to as this is only a test leave them hanging out of the trunk and back in through a side window/just don't pinch the wires creating a short). If there is a quick disconnect plug for the fuel pump can a wire be shoved into the connector and then warp it with tape to hold it into position and to keep the temporary connection solid ?. You could also maybe use one of the scotchclip style connectors to pinch through the factory wires insulation and if it is fully insulated make a connection into it with yet another terminal to where later you can unplug the test wires and leave the connector in place and not have any problems later with a short.
Let's say you think the fuel pump is loosing power. If you tap in a 12V light to the power input of the pump close to the pump itself and ground the other side of this test light then if power goes away the car will shut down and the light will go off. If it does go off then you have to move the test light connection further towards the source of power like the fuel pump relay until you find the problem but you have to go from one area to the next and not jump around. If you would then have it by the fuel pump relay and it doesn't go off but when it was further back by the pump and it did go off then between those two points there is a problem or a break in the circuit.
There is also no reason why you cannot add a second ground to something. Let's say the pump or whatever is grounded to something. This may be a good and clean connection but the something the wire is connected to may be bolted to another portion of the car and this connection is poor. Car body's are not one piece of metal but many sections bolted or welded to each other. By putting another connection under the factory one and running it to a different section of the car this could correct a problem as now the device is seeing a ground like it should. I've seen this before with a replaced fender being painted off of a vehicle and when bolted back on the mast antenna did not reference a ground as the fenders mounting bolts did not dig through the paint down to the fenders metal.
I hope some of this helps you out.
03-11-2006, 06:58:28 PM
The thing that stands out to me is not the fuel issue, but the fact you're having weird electrical issues. My instincts are saying to check and clean all your grounds.
When the car dies what happens? Do the dash lights go out, dim or stay normal?
03-13-2006, 07:30:49 PM
I'll say it one more time check your grounds.
03-16-2006, 03:23:48 PM
I finally took it to a professional yesterday. Paul's Garage in Westfield, NJ. He has a pair of '79 T/A, so he can't be all bad. Apparently what I thought was a minor coolant leak, destroyed the crank and cam sensors. And he repaired the engine ground at some spot. Congrats and thanks to those with the good advice. I wish I knew enough about automotive electronics to understand it. I still managed a new fuel pump, fuel filter, and fuel pump relay. At 187k miles, it makes for good insurance, even though it didn't solve the problem.