hey guys.

heres the problem im having.

in the last week ive put 2 fuel pumps in my car. 90 5.7 tpi.

fuel pumps seem to be overheating or getting really hot and breaking down.

i noticed the other night when i swapped out the pump thru my trap door was the pump and the gas in the tank was really warm after a 20 mile drive about 5pm.

now what im thinking is my flowmaster exhaust which is right under the tank is heating up the tank. i have the box where the pipes go in and then another set of dual pipes come out. im wondering if it makes sence that its heating up the tank/ pump and breaking it down.

took it on 200 mile trip today and been up since 4am so if it doesnt make sense sorry.

any imput? thanks guys

 

Is the heat shield still installed below the tank and above the muffler/pipes?
It takes a lot of heat to heat up a tank of gas.
Are you sure you're not overpowering the pump with too much voltage? You should see battery voltage at the pump.

 

ill check both. the flowmasters were put on before i bought the car.

ether that or autozone keeps selling me crap pumps. which i wouldn't be surprised. ive had to replace many things atleast twice in the last month due to that.

 

I would only recommend a walbro or delphi pump. There are some good threads on selecting one. Did you change the filter? That can add allot of unnecessary work for the pump. Is your tank full of crap? What do the pickup socks look like when you pull out the pump?

 

heat shield is there. socks weren't bad but replaced them anyways. outside fuel filter has been changed. there's not much crap in the tank but every time i put a no name autozone pump in runs great for a few days and then acts up when the engine is cold and other times to.

i took the bird around the block today and got up under there. noticed the flow master box was already warmed up but the rest of the pipes arent. thinking it might be clogged up and heating up?

when i get some time ill check the voltage.

 

Maybe your fuel pressure regulator is going bad. Have you tested the pressure and made sure it holds a bit?

 

I swore of Autozone years ago due to sub-par parts.

 

lol already have gone thru two fuel pressure regulators threw them also.
ill borrow my buddys fuel pressure gauge and see. the first fuel pump i had always ran at 30psi when it the lowest was suppose to be 40.

the regulator is fine. seems when it starts to cut out i give it more gas. stops cutting out but doesn't get up and go as it should for a couple secs.

 

ok put new pump in yesterday and took of flowmasters and nothing changed

runs horrible but when its about to quit or does. cut off engine and crank back on. doesn't run perfect but enough to get me acouple miles.

what should i check?

 

I don't believe you can kill a fuel pump that quick. New pump in and it dies a few blocks later? Nah, I don't buy the magic on this one.

You got good voltage going to the pump and AT the pump? Have you verified fuel pressure while running and see it drop off when the engine starts to die?

I think you've thrown enough money at new fuel pumps that you can safely say that ISN'T the problem. It's elsewhere- spend some time finding out where. The fuel pump is submerged in gasoline- it's nearly impossible to overheat it. However, since the car uses a return-style fuel system the gas that is returned to the tank is often very warm, having done a loop all the way up through the (hot) engine compartment and possibly past the (hot) exhaust.

 

alright. ive only been returning the pumps. yes fuel pressure dies when engine cuts out.

tonight getting a few tools to further find the problem.

 

haven't tested anything yet today but when it was barely running it threw code 44 for awhile then went away

 

Also keep in mind that the pumps themselves rely on the gasoline flowing THRU them to keep cool. The gas around the pump typically wont be enough to keep it cool if its dead-headed. The inside of the pump is fully exposed so the armature can be cooled by the fuel flow. If the flow of fuel is too low (blockage, bad regulator, etc.), the gas will boil inside the pump and allow the armature to overheat and burn up.