Car wont start

[95silvergt5.0]

Well......my car is being a dirty rotten whore.My car was having problems starting, but it seemed if I waited for the fuel pump to go off twice, it would start just fine. I replaced the fuel filter, no more problems, it ran fine for a couple of days. Now it is doing the same damn thing. Fuel pump?

 

[True 5.0]

If you can hear your fuel pump, then I would check elsewhere. Put a gauge on the fuel rail to check the pressure there. Although not the safest thing to do, you can disconnect the fuel filter, add a hose, and run the pump into a pail to check the flow. Don't by-pass the filter and run the car, however. Any little bits of crap will plug the injectors.

 

[donkey_punch]

i had a similar problem a little bit after getting my car. if i tried to just start it it would crank for a bit before starting. but if i let the pump prime it would start right up. my mechanic at the time told me that once i would turn the car off and it would sit for a bit the pump wouldn't hold pressure in the line. so i was trying to start the car with barely any fuel pressure. thats why if i let the pump prime for a few seconds it would have a chance to build pressure and have enought to start right up.

 

[95silvergt5.0]

aaa...im so confused. I just went out and turned it over and it started right up.

 

[HISSIN50]

As said, you need to note Fuel pressure before you go to start the car (and do so until it wont start). This will be helpful in your diagnostics.

Good luck.

 

[95silvergt5.0]

problems are persisting....what about that pressure relief valve? I remember reading something about that. Where is it located?

 

[HISSIN50]

problems are persisting....what about that pressure relief valve? I remember reading something about that. Where is it located?

You might have been reading about a part on another car - there's no pressure relief valve that I know of on a 5.0. There's the inertia switch, which kills power to the pump in the event of a collision. And there's the Fuel pressure regulator, which does as the name implies (regulates fuel pressure).

Diagnosing the issue will save you money (tossing parts at it). A FP gauge is 30 bucks and well worth the investment.

When it wont start, if FP looks good, I'd check spark and injector pulsing real quick. This will all take less than 5 minutes and will greatly narrow down the issue.

Good luck.

 

[95silvergt5.0]

Hmmm...well I pulled some codes on it and i guess my o2's are bad. This shouldn't affect the way the car starts though, correct?

 

[95silvergt5.0]

no cats on the car btw

 

[95GTV8]

i had a similar problem a little bit after getting my car. if i tried to just start it it would crank for a bit before starting. but if i let the pump prime it would start right up. my mechanic at the time told me that once i would turn the car off and it would sit for a bit the pump wouldn't hold pressure in the line. so i was trying to start the car with barely any fuel pressure. thats why if i let the pump prime for a few seconds it would have a chance to build pressure and have enought to start right up.

So you had a faulty fuel pump? Did you have any performance problems in the upper RPM's. I'm in the same boat as you are where I have to prime it to start it, or it will just crank forever.

 

[HISSIN50]

Donkey punch is describing either a weak pump and/or a bad check valve in the pump assembly (it keeps fuel from backfeeding).

The O2 codes could relate to running lean from a weak pump. You really need to see real time fuel pressure or wideband A/F ratios.

Good luck.