Xposure

My car is a 1996 Formula with mainly bolt ons. It always start up easy in the mornings but once I take it for a spin and come back later it does not start up anymore it will just crank. I have replaced opti, coil, icm, wires, plugs, fuel filter and cleaned the throttle body with no change. I tried spraying some carb cleaner while attempting to start the car and it worked. So I'm guessing fuel problems are the cause but don't know what exactly to check? Fuel pump maybe?

ZFreie

Before you start throwing parts at it find a cause first. With that said.

Have you checked the fuel pressure yet?

Xposure

No I haven't but I will be doin that today.

ZFreie

http://shbox.com/1/4th_gen_tech2.htm...essure_testing Start there and lets us know what you find.

Xposure

Fuel pressure tested at zero. I tried hearing for the pump to prime and nothing so what should I be looking for now?

Xposure

The car still turns on in the morning just not after running for a while or when its hot outside

Xposure

Tested the fuel pressure out and it was at 40 and jumps to 50 when I take off the vacuum line from the regulator.

ZFreie

Wait, so, was the pressure 0 or 40?

Your going to have to get the car to not start first, then test the fuel pressure. Gotta get it to act up to find the problem.

Xposure

Ok I let the car idle this mornin and the pressure was at 40 the whole time it ran. I shut it off and tried to start it up but the pressure was at 0. So now it won't start up at all.

ZFreie

Does the pump prime when its showing 0psi?

Xposure

No it does not

ZFreie

I dont think the pumps faulty because the pump wont even prime. Every time Ive seen a pump fail it will still prime and attempt to work, but cant come close to pushing enough fuel.

If it were me i would be checking to make sure power is getting to the fuel pump after its hot.

It could be the wiring harness going into the pump. I don't know of any easy way to check this, aside from doing the trap door mod to get to the fuel pump https://ls1tech.com/forums/lt1-lt4-m...-mod-pics.html . But that only works if your willing to cut your car.

I hope others will chime in, because I'm not convinced your pump is bad. I also don't know where all you can check for power to the pump other then at the pump its self.

This is only my .02. Just repeating info Ive seen around. Its your car so do what you feel comfortable doing.

Xposure

It is mostly for the drag strip so I am willing to cut it up.

ZFreie

Well, Ive pretty much exhausted my knowledge of the matter. Try searching the forums using the search tool. There is a lot of useful info on here.

If it were me, Id start checking for power back to the pump, and if you DO have power back to the pump when its hot, then I would suspect the pump to be faulty.

Hope its a simple fix and you figure it out.

Someone else throw some advice at the guy, I've got nothing left in the noodle.

Xposure

Well thanx for the help so far! I wonder is a relay is necessary at the moment?

SS RRR

iTrader: (2)

I think your pump is overheating causing it to act up once it gets warm. Is it the stock pump? If it has been replaced was the fuel pump bucket used again?

Xposure

I think it had been replaced and when I took it out it looked pretty clean and new

Xposure

Pulled the following codes

P0335
P0154
P0134
P0336
P0403
P0443
P1641

SS RRR

iTrader: (2)

http://shbox.com/1/Dtcs.htm
(click on the OBD-II tab at the bottom of page.)
Does your car still have the evap and EGR? For the O2 sensor and crank position sensor I would check the harness first to see that it is not burned or damaged in any way...

Xposure

No 02 sensors on the car right now and I have deleted the evap system, air and egr. I have also installed a manual fan switch so that might be the reason for the fan relays code