Fuel Pump Problem

[bukemdano]

I have a 97 Grand Prix, GTP It has a new fuel pump. All of a sudden the fuel pump will not work when trying to start. I turn the ignition on, and the pump does not turn on and car wont start. I have driven this car for a month and it never dies when driving down the road, only when sitting and trying to start again. It has done this twice now. It sits for a couple and days and it starts miraculously, the second time it happened it didnt. So, I had it towed to the mechanic and it started...lol but, he cant figure out what's wrong with it. The fuses are fine. I would be greatful for any help or ideas to fix this problem. Thanks AloT !

Dan

[BNaylor]

Welcome to AF.

Just to clarify so are you saying no fuel pump prime which is the two seconds it activates at Ignition to ON? Have you tried switching out the fuel pump relay with the fuel pump speed control relay. The relays are controlled by the PCM module.

When it does start does it die within several seconds or less? If so run the fuel pump resistor bypass procedure located at our Tips & Maintenance forum.

[brcidd]

The last 5 or 6 fuel pumps I have changed on any vehicle act like yours did- they don't engage or start pumping- UNLESS you disturb it- by whackking on the tank with a rubber mallet or yor fist etc-- This is one of the typical failure modes of a worn out fuel pump. The bushings are worn- disturbing it centers the armature- and the pump starts running- but it will do it again- I've seen folks drive their vehicles 6 months by pounding on their fuel tanks every time it would not start. Some would say that the armature just stopped in a bad spot- it may start pumping 9 of ten times from here-on-- but believe me it needs to be changed-- especially if all other electrical diagnosis suggested above checks out...

I liken it to a worn out blower motor-- once they start running- they keep running- that is why you don't stall out while driving.... Blower motor do the same thing when they are worn out-- you bang on them- they start and keep running until shut-off- and then they may or may not start again....with out some help.

[BNaylor]

Originally Posted by brcidd

This is one of the typical failure modes of a worn out fuel pump.

Hammer modulation?

Did he not state the fuel pump was new?

[usedranger]

Could be a defective pump...if the mallet modulation works, new or not, its defective. Had that happen once or twice. Dropping a tank twice is just sooo much fun.
Maybe somone else can tell you how to jumper that model pump to test it out. If it is a dead armature maybe you can "cycle" it to where it does not run then you can try the mallet trick.

[BNaylor]

Originally Posted by usedranger

Dropping a tank twice is just sooo much fun.

We don't need to drop the gas tank on '97-'03 model Grand Prixs to work with the fuel pump assembly so please get your advice straight.

[usedranger]

Geee sorry. I was referring to my dropping a tank twice on a completely different vehicle, not the location of the pump on the "97 GP. Either case doing something twice is not fun IMHO.

[doctorhrdware]

I would rather do it even 4x on a 97 GP than having to drop the fuel tank IMHO.