What would cause a fuel pump to not work when engine is hot?

[xminnis]

I have an '86 fuel injected 4.3L V6. Only when the engine is hot the fuel pump will not work. It cant be the pump itself because I have always heard they either work or don't, they can't work part of the time (unless that is an old wives tale). My first thought was the relay, but it is kicking fine. Could it be the main computer, ECM or whatever it is called?

 

[pontiacgp]

Re: What would cause a fuel pump to not work when engine is

could it not be the pump is overheating and the thermal protection is shutting it down

 

[GhettoRacingKid]

Re: What would cause a fuel pump to not work when engine is

i assume its an electric pump?

it could be over heating..

also there could be a hole in the line and you could be getting air lock (doubt it since its an electric pump.)

i think its over heating and shutting down. the sock might jsut be clogged.

 

[xminnis]

Re: What would cause a fuel pump to not work when engine is

What is "the sock"? Sorry I am not that mechanically inclined, just too poor to take to a shop.

 

[pontiacgp]

Re: What would cause a fuel pump to not work when engine is

the sock is the filter in the gas tank...do you have another pump you can try?

 

[GhettoRacingKid]

Re: What would cause a fuel pump to not work when engine is

its basiclly a filter/strainer for the fuel pump so it doesnt hit the sh*tter the second your drop it in.

here is a pic of one on a fuel pump... you can see all the dirt and crap it keeps out.

have you checked the fuel filter if its clogged? that needs to be changed also.(it could be getting clogged there preventing the flow and heating up the pump causing a shut down)

 

[xminnis]

Re: What would cause a fuel pump to not work when engine is

Yeah the fuel filter has been replaced relatively recently, and no i do not have another pump to try unfortunately...

My problem sounds exactly like this:
http://askville.amazon.com/car-start-ru ... d=10100618
so I am a little worried that it is something like this where I will replace everything on the car and not fix it.

I have replaced spark plugs, EGR valve, ignition module, ignition coil, and ruled out the pump relay, MAP sensor, and throttle position sensor....

 

[xminnis]

Re: What would cause a fuel pump to not work when engine is

OK so i have some new information.... It doesn't actually appear to be caused when the engine is hot, but just after it has been driven . Take last night for example. It was like 40 degrees, the car started up fine because i hadnt driven it all day. I drive to walmart which is barely a mile away if that so there is no way the engine got too warm, then I was inside for about half an hour and when I came back out it would not start. finally after cranking it for 10-15 minutes it randomly starts 1/50 times as usual. Then I drive another half mile to blockbuster hop out and leave it running this time. I am inside for about 5 minutes when I come back out it had stalled, so i was like great i will be stuck here now, but it fires right up. Then I drive home and when i get home and cut it off i wait about 5 minutes just to see if it would start and it will not start now...

 

[Bonnewagon]

Re: What would cause a fuel pump to not work when engine is

I'm thinking fuel pump relay. Find it, jump it, test. Plus they are cheap enough to just change to eliminate it as a culprit.

 

[xminnis]

Re: What would cause a fuel pump to not work when engine is

I have been told this car doesn't have a fuel pump relay.