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Fuel Pump Replacement?

S

swoollis

New member
I have a '99 Grand Prix GTP (3.8L V6 Supercharged), and I have been having problems with it failing to start. It had been running well without issues, then it wouldn't start. I had it towed to a service center, and it fired right up. They couldn't find the cause. Same thing happened again, and again started right up after the tow. The third time it happened, the engine started but then ran rough and stalled, and now won't restart at all. Had it towed to a service center again, and they say it needs a new fuel pump, but I'm not convinced that is the problem? Anyone had similar experiences?

Thank you!
 


As fuel pumps become weak they also get finicky. Sometimes they work sometimes they don't. Sometimes they only work when it's cooler then start giving you issues.

Two other things come to mind with your symptoms as well. CPS and Fuel pump resistor. Try bending the #85 tab on the fuel pump resistor.
 
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I'll give that a try. I've been thinking it might be the crank sensor too, and I've got one on order.

Thank you!
 
swoollis said:
I'll give that a try. I've been thinking it might be the crank sensor too, and I've got one on order.

Thank you!
Click to expand...

NP, mine is doing the same thing so I feel your pain. I'm pretty sure I've isolated mine to the fuel pump though. As it's not even priming.

I have a Caspers fuel pump rewire so the resistor is bypassed. :)
 
Check the relay,i like to check all the cheaper parts first. But,that's just me.

Free mcbump

Or possible bad ground somewhere?
 
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I had my car towed home from the shop (they were going to charge me almost 500. for a new fuel pump & 150. labor) and the driver got in to unlock the steering column, decided to try to start it, and once again, it started right up. He asked what they told me the problem was, and I said the fuel pump (they told me it was fried and there's no way it would start again). He shut the car off, turned the key and said "hear that?" and I said "yeah, that's my fuel pump". So I have no intention of taking my Pontiac to them again obviously. I'm going to try to troubleshoot it myself tomorrow. Thanks to all for the helpful advice.
 
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A pump is nothing more than an electric motor with fins on the end. It's possible the difference of warm/cold can make it work/not work.

I have a fuel pressure gauge that I modified with an extension. This does two things depending on the configuration I use.

1. There is a tube on it that will connect to the supply quick connects. I can connect it before the fuel filter or at the fuel rail before the regulator. This is a great way to check and determine if the pump is bad.

2. The longer hose allows it to be connected to the fuel rail schrader and be driven. Some pumps will give great results with key click tests and idling. Yet when a demand is placed on them, they may not keep up. A driving fuel pressure test shows these issues.
 
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