Okay, now I'm getting really pissed off. (fuel pump)

[CheeseSteakJim]

You guys have all seen the thread about my mysterious fuel pump issues by now. Everything checked out fine and the fuel pump worked perfectly when jumpered to the battery, yet it wouldn't start. Eventually I fixed it.

Then the replacement fuel pump blew after three months, and the car had only been started maybe 20 times in those three months. I tested it, and it had in fact failed. These things have lifetime warranties on them. They're never, ever supposed to fail. Nevertheless, I brought it back to the store and they replaced it with an identical pump. Everything was hunky dory.


Until a couple days ago. I hadn't started the car in a couple weeks, and I figured I'd take it out for a short spin up the road. At first crank, the fuel pump didn't turn on. I heard the relays click on and then off as they should. Then I tried again, and the fuel pump came on fine. Just now, I went to start it and no fuel pump, just relays. Even after I cranked it a few times, no pump sound. I tested the voltage at the fuel shutoff in the trunk, and it went up to 11/12v and back down to 0 in conjunction with the sounds of the relays.

What the fuck? This car needs to be on the road in a few weeks, and it has to last me all fucking winter. Does anyone have any suggestions as to what might be fucking with my car so badly? I have not yet tested the fuel pump to see if it's dead, but if it is I'm going to be extremely fucking angry, if you couldn't already tell. I don't need to be dropping the fuel every fucking month in the dead of winter.

Man, I love this car but after the thousands of dollars I've spent on getting it back together and running, I don't need this bullshit with fuel pumps all the time.

[gadget73]

Are you sure the relay is good and the connection at the plug in the back is making a good connection? Fuel pumps seldom die. I pulled one at 160k from my car and it worked fine. Replaced it because I was installing a new fuel tank.

[CheeseSteakJim]

Are you sure the relay is good and the connection at the plug in the back is making a good connection? Fuel pumps seldom die. I pulled one at 160k from my car and it worked fine. Replaced it because I was installing a new fuel tank.

I replaced the fuel pump relay (and another one in that cluster, but I can't remember which) around six months ago when I first got this car running. If I had a bad connection at that little connector that's above the fuel tank, would it still show me the spike up to 11/12v on my multimeter? Same question for a bad ground or bad relay. To me, it seems like if I'm getting that spike from 0 to 11/12v at the fuel shutoff in conjunction with the clicking of the relays, that would say to me that the fuel pump is not functioning, unless the fuel shutoff is the issue. Am I wrong?

I swear I'll never fully grasp electrical work no matter how many people beat it into my skull, so bear with me. Sorry if I'm asking dumb questions again and again.

[Pirate]

Have you ever replaced the ignition switch in this car? I had a similar problem with a 1988 Cougar...worn-out ignition switch, intermittent pump problem. It's something to think about..unless you have a direct short somewhere, I don't see what the problem is...

[Kleetus]

Where did you get your fuel pump from?

[cld783]

try a different battery.

[CheeseSteakJim]

Where did you get your fuel pump from?

My job, a CarQuest supplier.

try a different battery.

It's not the battery. This battery is less than three months old. I also checked it and fully charged it using our equipment at work.


When I threw a multimeter on the two terminals that go into and out of the fuel shutoff, I'd get around 8v when I turned the key to on. If I go from the positive side of the fuel shutoff plug, and touch the negative side of the multimeter to bare steel (in this case, directly to the fuel pump ground, which is also in the trunk), it gives me over 12v. I'm thinking it's got to be a bad ground. I'm going to have to drop the fuel tank and examine the harness. I've been sick this past week so absolutely nothing has gotten done, but hopefully if I have the time and motivation tomorrow evening I'll pull the tank.

[gadget73]

If you're metering across the 2 wires on the fuel pump cutoff, you're not going to get proper voltage. Its grounding through the pump, so the motor itself acts as a resistor and drops the power down. It does however indicate that the motor isn't open, and that its got a ground to the motor. Try checking the voltage at the plug under the car for the fuel pump. It should be up near the body, where the wire runs over the top of that metal crossmember. If thats +12v, then your pump is getting power. If its not running, then its probably bad. That, or the ground is really marginal and its getting enough power to show on a meter but not run the motor.

[CheeseSteakJim]

Well, the pump's bad. I jumped it with a battery and nothing happened. It's less than two months old. What the hell?

My only guess as to why this has happened again is that the fuel tank was so filthy with sediment that it clogged the sock filter enough to make the fuel pump burn itself up. Remember, this car hasn't been a daily driver in over a year, so it's been sitting for that long with low gasoline in the tank. I drained out all the gasoline and it does have a nasty gooey residue along the bottom of the tank.

I can just hose the tank out with a garden hose, can't I?

Good thing these pumps have lifetime warranties. Tomorrow I bring this pump back, get a new one, clean out the tank, and fucking hope that a digusting tank was blowing these pumps, because I can't figure out what the hell else would.

EDIT: The fuel pump harness was pristine, by the way. No kinks, holes, or rub marks. I tested it with my multimeter also and it came out fine.

[gadget73]

not sure that I'd use water to clean the tank. Something oil based would be better, kerosene, mineral spirits, etc. If its that nasty, just buy a new one. When mine sprung a leak I think it was like $130 in stock at Advance.

[CheeseSteakJim]

Okay, it was a bad pump for sure. Dropped the tank and looked inside. I found a wall of grime along the inside of the tank that ended right about where the gasoline sat for several months without moving at all. It has to be all the shit in that tank that blew this pump. Cleaned the inside of the tank by sealing it off and splashing acetone around inside, then pouring it out, then scrubbing the inside with a rag on the end of a broomstick, then splashing another half-gallon of acetone around, then water, then letting it dry. That did the trick.

Then I got ANOTHER pump, this time a Bosch instead of an Airtex, and adapted it to the Airtex bracket. Put it in, and put the tank back in just now. Took the car for a nice ride up the street. It's nice to hear it run again... I hope it continues running because I need it for school this winter.

I hope my car isn't cursed to destroy every fuel pump it gets. Everyone keep my fuel pump in your prayers. It's up against some bad odds.

[86VickyLX]

We need a prayer smiley! :lol:

[gadget73]

sounds like time for a brandy new fuel tank.


You know the stock fuel pump was Bosch right? Where did you get a new hanger for yours? I adapted my stock hanger to fit the Walbro Mustang pump which was much smaller, but I've never seen replacement hangers available.

[CheeseSteakJim]

sounds like time for a brandy new fuel tank.


You know the stock fuel pump was Bosch right? Where did you get a new hanger for yours? I adapted my stock hanger to fit the Walbro Mustang pump which was much smaller, but I've never seen replacement hangers available.

Hopefully I don't need a new fuel tank. The thing was spotless on the inside when I was done with it. Let's hope it stays that way.

The Airtex pump I had gotten (twice) came as an entire assembly. Then my dad threw away the stock one, so when I got JUST the pump (Bosch) I was stuck with having to adapt the hanger to the pump, and the pump's electrical connections from a spade connector to a ring connector. Adapting the hanger was a pain in my ass because the pump was way too large for the hanger, but I figured it out.

[gadget73]

Hm, see the problem with the Walbro pump in the stock hanger is that the stock hanger is too big. I wonder if those hangers are available seperate, it might make for a neater install vs my rig with the hose clamp holding the pump to the hanger.