Mechanics

FUEL PUMP KEEPS BREAKING

Chevrolet Astro

Hello I have Chevy Astro Cargo 1999, 6Cyl 4L with automatic transmission, 150000+ miles. I own this car for over 2years and since then I have replaced my fuel pump 5times. Last time I replaced the fuel pump was in May 2007 and it seems like its gonna break again. Here is the problem I have lately, I parked the car after 1hour driving and I couldnt start again, I tried it 30min later and it started fine. Next morning car started fine and during that day it quit working again several times. Once when I was driving I could feel that the engine doesnt have enough fuel and the car shut down in the middle of road. It looks like when its hot it wont work. One mechanic replaced fuel filter, ignition coil, ignition module, ignition ditributor rotor, cap and this small plastic part that goes into the ignition rotor i'm not sure whats the name of it. And its still didnt help. He said it might be fuel injector. I went to different mechanic he hooked up computer to check everything and he couldnt find the problem. Then he checked fuel presure when the engine was cold and everything was ok, then he was driving the car for 30min, turned the engine off and he couldnt start again, checked the spark plugs and it was ok, checked the fuel presure again and it didnt have enough presure coming from the tank. So it looks like that the fuel pump is dying again after 2months. Can you please help? Thx.
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Honza66
July 24, 2007.




In order to " test" your fuel pump, I need for you to understand a few things. Your's and cars nowadays have a fuel pump relay. This only primes the fuel system for a few seconds when you first turn the key on or off. It is the oil pressure switch that runs the fuel pump when the engine is running and you are driving. So, first of all, when the engine dies, turn the key off and back on and see if you hear the fuel pump run. Then see if it starts. If it does, then there is a problem with your oil pressure switch or the wiring to it. These new oil pressure switches have 4 wires. 2 for the fuel pump and 2 for the oil light or gauge. Also, carry a can of starting fluid and when it dies, spray some into the air intake and see if it hits. This will tell you if you have an ignition problem with some part of the spark system breaking down, cooling off, and then working again.[/Quote: 5898a220cc]

Yeah we tried that, and we could hear the pump. But it wont start again untill it cools down. I just talked to my mechanic, he said that the fuel presure is only 30psi after the engine died. And he tried the trick with starting fluid and the engine started fine. I remember before, all the other pumps that I replaced I could tell that they will die because they had wierd unsteady sound right before they died. So something is killing the fuel pumps. Could it be electrical problem or maybe sludge or something in the fuel tank? Thx.

Tiny
Honza66
Jul 25, 2007.
Ok.I will replace that and check the wires. Thank you very much
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Tiny
Honza66
Jul 26, 2007.
How bout my 2 penny opinion?
1 thing here bother me a lot. WHy. WHY 5 PUMPS IN 2 YEARS. Doen't it sounds strange.I mean weird.
Let's talk about fuel pump.
So far my understanding on pressure test. It only reflects the condition of the regulator on a conventional return system. Another word not 1 of those ford returnless system with 9 amp ctrl by PCM. We had plane jane chevy 90 pu' with TBI coming in with a pressure gage standing @ 14 psi and will not rev above idle.I put my CODA and no volume at all. So. Any1 bother to chk the volume flows under a load or while it is crapping out.
Its gotta be something cuzing the pump crapping out.5 times.5 times man. Any air pocket bad connection will show on a low amp current wave form. Why aint ur mechanic use a current probe and calculate the rpm pump speed with factory spec current. Last but not the least. Is it an a/c delco pump. Put an O.E.M. Pump and a cheap pump on a scope. And u gonna see the comutators differences. Unless u buy into the crap as lifetime warranty and getting em' 5 in arow. That won't surprise me neither. Seen that. Been there and also done that.U all think I'm good enuff to take that moderator test yet. Heh heh heh

Tiny
Kin chan
Jul 26, 2007.
Current wave form w/low amp probe should review pump speed without removing nothing. Lot more faster & easier. Whether too much or no resistance. Voltage won't reflect any tell tales sign. Only amperage waveform reflect abnormal condition.

Tiny
Kin chan
Jul 28, 2007.

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