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Posted: 9/11/2010 8:22:33 PM EDT
I replaced the factory fuel pump in my 89 Pontiac 6000 around 2 months ago. The replacement failed after about 2 weeks and less than 100 miles. The parts house, Rock Auto, replaced it with an identical pump and it ran for another 10 days and just failed again today after about 30 miles.

I'm not letting the gas go below 1/2. I'm putting on the new strainer, I replaced the fuel filter. After the first replacement failed I replaced the fuel tank too, thinking a big dent in the bottom might be making it the pump run dry. I can't find a replacement harness but the original looks and tests good.

The pump I'm using isn't the most expensive pump on the market, and it fact was the least expensive pump RA had that fit the application, but two weeks is a little ridiculous.

Any ideas? Is it possible that this can be something other than just crap parts or bad luck?
Link Posted: 9/11/2010 8:29:14 PM EDT
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.
Link Posted: 9/11/2010 8:33:33 PM EDT

Originally Posted By fxntime:
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.

This can be said for just about anything...


I don't know about your particular model, but when I did my fuel system upgrades one of the most important aspects was a larger diameter pickup. The pump doesn't have to work nearly as hard with a bigger straw.
Link Posted: 9/11/2010 8:36:32 PM EDT
Originally Posted By DuraToTheMax:

Originally Posted By fxntime:
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.

This can be said for just about anything...


I don't know about your particular model, but when I did my fuel system upgrades one of the most important aspects was a larger diameter pickup. The pump doesn't have to work nearly as hard with a bigger straw.


True, but in tank fuel pumps are a particular PITA to change out over and over again.
Link Posted: 9/11/2010 8:51:08 PM EDT

Originally Posted By fxntime:
Originally Posted By DuraToTheMax:

Originally Posted By fxntime:
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.

This can be said for just about anything...


I don't know about your particular model, but when I did my fuel system upgrades one of the most important aspects was a larger diameter pickup. The pump doesn't have to work nearly as hard with a bigger straw.


True, but in tank fuel pumps are a particular PITA to change out over and over again.

I've never done one, my diesel is the only vehicle I've dropped the tank on.

As it so happens, mine was a pretty simple process; two bolts, a strap and a hose clamp and the thing was free. Hopefully on the OP's model it's a similar procedure, GM has traditionally made their vehicles relatively easy to work on.

On some of the other makes, dropping the tank is akin to open heart surgery.
Link Posted: 9/11/2010 9:30:31 PM EDT
Originally Posted By fxntime:
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.


It's an old car we keep as a spare. I didn't want to put a $200 pump in a $300 car. Wouldn't you think that even a cheap pump would last more than a week? The fact that two new pumps failed in such a short time has me wondering if it can't be something causing them to fail, but I can't think what it might be.


Posted Via AR15.Com Mobile
Link Posted: 9/11/2010 9:33:14 PM EDT

Originally Posted By 3rdpig:
Originally Posted By fxntime:
Never ever buy cheap fuel pumps. NEVER! Whatever you will save initially will be spent 5x over doing it over and over and over again.


It's an old car we keep as a spare. I didn't want to put a $200 pump in a $300 car. Wouldn't you think that even a cheap pump would last more than a week? The fact that two new pumps failed in such a short time has me wondering if it can't be something causing them to fail, but I can't think what it might be.


Posted Via AR15.Com Mobile

Check the wiring to the pump maybe?
Link Posted: 9/11/2010 9:46:10 PM EDT
[Last Edit: 9/11/2010 9:47:44 PM EDT by SteelLucky]
Link Posted: 9/11/2010 9:47:24 PM EDT
I've checked the wiringtwo or three times. And while I can see that bad wiring can cause the pump to not run, I don't see how it can make the electric motor fail entirely. And the pump, and the car, run fine till the moment of failure

Posted Via AR15.Com Mobile
Link Posted: 9/11/2010 10:15:12 PM EDT

Originally Posted By SteelLucky:
This may have some ideas.

http://www.airtexproducts.com/AIRTEXpdfs/Airtex_TTS_2008.pd
I appreciate it, but the parts about why might cause a new pump to fail, dirt in the tank, rust, plugged filter, have all been considered and dealt with. I've got a brand new fuel tank, new filter and new strainer. I suppose it could be an obstruction in the line, and I'll check for that, but the car runs great and fuel pressure at the manifold is fine up till the moment the pump fails.

Tomorrow I'm going to pull the back seat out and cut a hole in the floor so I can access the pump. Pulling the tank isn't cutting it when I have to do it twice a month. I'll test the pump by applying 12 volts directly to the motors terminals, but I'm pretty sure it will be dead like the last one.
Link Posted: 9/12/2010 2:45:40 AM EDT
Buy only AC Delco pumps, check power and GROUND, you need to be under .1 volt drop on the entire ground circuit. Also on the older vehicles check the sender/module the fuel pump fits in the connectors in them go bad a lot!!
Link Posted: 9/12/2010 8:25:15 AM EDT
[Last Edit: 9/12/2010 8:26:02 AM EDT by 3rdpig]

Originally Posted By DonofKalifornia:
Buy only AC Delco pumps, check power and GROUND, you need to be under .1 volt drop on the entire ground circuit. Also on the older vehicles check the sender/module the fuel pump fits in the connectors in them go bad a lot!!

Could a bad ground or the sender/module cause the pump itself to fail? I mean not run at all when I put 12 volts from an external source to the pump terminals?
Link Posted: 9/12/2010 8:40:23 AM EDT
ONLY use Delphi/factory (sometimes AC/Delco-some models) pumps in GM products!!!! Some of the retail parts chains sell them at good prices, but make sure its a Delphi.
Link Posted: 9/12/2010 9:23:34 AM EDT
Originally Posted By urbanpi:
ONLY use Delphi/factory (sometimes AC/Delco-some models) pumps in GM products!!!! Some of the retail parts chains sell them at good prices, but make sure its a Delphi.


I've replaced over a dozen fuel pumps on GM's.

I've never had a non OEM (AC/Delco, Delphi) pump last more than a year. That's a total of 6-8 pumps. None of the brands that were recommended to me as being good to go (including Napa and Bendix) held up. I think the shortest life I've seen out of a factory pump was 3 years.

Aside from being a crappy pump out of the box - fuel contamination. Ethanol plus water can be deadly to certain pumps - Plating is wiped off the motor commutator and the motor fails. This is a particular problem with certain years of Hondas (per a friend who is achemist in the fuel industry), but can be worse with aftermarket pumps. I'd normally point to crap in the tank, but a new tank should have that addressed.
Link Posted: 9/12/2010 9:38:04 AM EDT
Is the wiring harness providing the proper volts / amps? (Not wire damage, but is it giving the right juice?)

It could be something else in the system entirely. (Dunno if cars still have these, but a bad voltage regulator can do all sorts of weird stuff.)
Link Posted: 9/12/2010 9:53:06 AM EDT
[Last Edit: 9/12/2010 9:53:26 AM EDT by 3rdpig]

Originally Posted By RR_Broccoli:
Is the wiring harness providing the proper volts / amps? (Not wire damage, but is it giving the right juice?)

It could be something else in the system entirely. (Dunno if cars still have these, but a bad voltage regulator can do all sorts of weird stuff.)

Yes, I've checked for both voltage and amperage.

And I keep asking but so far no one can or will answer, but I'll ask you too. Will a bad ground or wiring wreck the pump in less than 50 miles driven? And I don't mean just not run normally, but totally wreck it so that when I put 12 volts from an external source directly to the pump terminals, skipping ALL the wiring and grounds in the car, it won't run. And will that bad ground or wiring also allow a new pump to work fine and the car run fine, till the moment it dies?

That's what's throwing me. The only answer I can come up with is junk parts. But I can understand them selling pumps that don't last a year, but ones that don't last 2 weeks? They have to know they're going to be returned.

Anyway, going out to work on it again. This car is exhausting me. Pun intended.
Link Posted: 9/12/2010 1:16:56 PM EDT
Originally Posted By 3rdpig:

Originally Posted By RR_Broccoli:
Is the wiring harness providing the proper volts / amps? (Not wire damage, but is it giving the right juice?)

It could be something else in the system entirely. (Dunno if cars still have these, but a bad voltage regulator can do all sorts of weird stuff.)

Yes, I've checked for both voltage and amperage.

And I keep asking but so far no one can or will answer, but I'll ask you too. Will a bad ground or wiring wreck the pump in less than 50 miles driven? And I don't mean just not run normally, but totally wreck it so that when I put 12 volts from an external source directly to the pump terminals, skipping ALL the wiring and grounds in the car, it won't run. And will that bad ground or wiring also allow a new pump to work fine and the car run fine, till the moment it dies?

That's what's throwing me. The only answer I can come up with is junk parts. But I can understand them selling pumps that don't last a year, but ones that don't last 2 weeks? They have to know they're going to be returned.

Anyway, going out to work on it again. This car is exhausting me. Pun intended.


Very high voltage to the pump may cause premature failure - but that should be causing lots of other problems as well. (Like blown headlights)
Intermittent voltage / losing ground shouldn't bother a DC motor much. DC motors are usually pretty tolerant of voltage variations.

Can you monitor system voltage while you drive?
Link Posted: 9/12/2010 4:16:06 PM EDT
Originally Posted By 3rdpig:

Originally Posted By DonofKalifornia:
Buy only AC Delco pumps, check power and GROUND, you need to be under .1 volt drop on the entire ground circuit. Also on the older vehicles check the sender/module the fuel pump fits in the connectors in them go bad a lot!!

Could a bad ground or the sender/module cause the pump itself to fail? I mean not run at all when I put 12 volts from an external source to the pump terminals?


Yes, a bad ground will cause a excess amp draw. Ground are very cheap to fix, on the GM trucks I will just make a new ground near the pump on the frame. The ground for the fuel pumps on GM trucks is a stud on the very left rear of the frame shared with a bunch of other circuits.
Link Posted: 9/12/2010 5:28:46 PM EDT

Originally Posted By Lost-Drive-In:
Originally Posted By 3rdpig:

Very high voltage to the pump may cause premature failure - but that should be causing lots of other problems as well. (Like blown headlights)
Intermittent voltage / losing ground shouldn't bother a DC motor much. DC motors are usually pretty tolerant of voltage variations.

Can you monitor system voltage while you drive?

I'm seeing no signs of higher than normal voltages, no fuses are blowing or anything like that. The first new pump that failed blew the fuel pump fuse when it went tits up, but other than that it's the only fuse that has blown.

I haven't monitored voltages, but it wouldn't be that hard for me to set it up.
Link Posted: 9/12/2010 5:36:14 PM EDT

Originally Posted By DonofKalifornia:


Yes, a bad ground will cause a excess amp draw. Ground are very cheap to fix, on the GM trucks I will just make a new ground near the pump on the frame. The ground for the fuel pumps on GM trucks is a stud on the very left rear of the frame shared with a bunch of other circuits.

I'll check the ground the next time I work on it, the manual tells me the location, I'll make sure it's a solid ground.
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