My car's fuel pressure is 29lbs. with key on. The car won't run. I can sometimes get it to start, but then it stalls about 3 seconds later. If i give it ANY throttle it will immediately stall. The fuel pump and ECM are new. fuel filter maybe has 5K miles on it in the last 3 years since it was replaced. Any ideas?

 

i had a similar problem, it was the air gap between the pickup coil and reluctor wheel in the distrubutor was too large. if that is your problem your spark plugs will be fouled and will need to be replaced

 

how would that give me low fuel pressure?

 

If you have 29psi with the key on and engine off it will drop to about 20psi when full engine vacuum is applied to the FPR at idle. Before starting the engine remove the vacuum line to the FPR and plug it. Then see if the engine will idle, or stays running longer.
Remember just because something is new doesn't mean it can't be defective, but assuming it's a good fuel pump and electrical is good (no excessive voltage drop) give the following some thought.
The symptoms of a bad fuel pressure regulator include:
Lack of fuel pressure, excessive fuel pressure, black smoke and rich engine running condition, instant drop of fuel pressure once the vehicle has been turned off, delay building sufficient fuel pressure.

Don't forget to replace the spark plugs once you get the pressure back up because they're probably fouled by now.

It's also possible you're leaking fuel back into the tank resulting in a pressure loss.

 

ok. so its a tpi. see if there is a rubber section of fuel line somewhere in the fuel return. completely pinch the hose, turn the key on and see if the pressure goes up to spec. if so its likely a stuck-open regulator. if not make sure you have 12.5 volts at the fuel pump, if you do it has to be a bad/wrong fuel pump. the distributor does suppy a cam signal to the ecm

 

Distributor reference signal not needed to start engine only for ECM to control, but not below 400rpm. in other words engine must start before ECM can control the engine.

 

thanks alot guys, as i turns out i don't think the pump has been replaced. I had everything torn out because we thought the pump was bad when it turned out to be ok. this was about 6 months ago. Man i'm pissed i didn't replace it back then. Think i might try the access hatch method this time though. First i'll check the other things in regard to the regulator. thanks i'll keep u informed.

 

ok so i pinched off the return line and it did not change anything. Would it pretty much HAVE to be the fuel pump at this point?

 

Today i hooked up my Fuel pressure gauge to the output end of my fuel filter. What should the pressure be at this point?

 

38-48 psi

 

yeah i have like 30 after the filter so that would eliminate the possibility for the regulator being bad right? I also checked my voltage at the pump. The purple wire has 11V and i got nothing at the gray wire. What supplies the gray wire with voltage?

 

i think there should be 4 wires to the tank. pump power, ground, and two wires for the fuel level sensor. 11 volts is only ok if the battery is 11 volts. you should be within 1 volt of battery voltage. i'm not so sure you can get that pump out through the hatch unless you plan on cutting a big hole in your car

 

no there are definatly only three wires. i need to know what the gray wire does, cause i have no power to it.

 

Psi at the pump should be higher than rail psi as there's still several feet of tubing plus the fittings, filter and regulator.


Wiring:
My three wires are:
Tan - pump 12V from fuel pump relay
Pink - fuel gauge (voltage depends on fuel level; ignition must be on)
Black - ground for both pump and level sensor.

 

should both wires have constant power?

 

If the key is on and engine off the fuel sender will have voltage, and the pump will only have voltage while priming.