91
chevy
camaro
5.0
87k

Hey , I Just purchased a 91 camaro rs 305 and when I start the car it runs for a couple seconds and then alot of fuel dumps on the top on the two butterfly valves that open when you start the car and it makes a hissing noise like air is coming out thats loud, and the car shuts off but when i started it another time the fuel wasnt spraying as much and the noise was not there.

Your having a problem with the overfueling for some reason. The hissing noise is just the idle air control opening up trying to overcome this. This could be bad injectors, computer, related wiring or other things. You need to use a professional scan tool to examine the sensor data to give you a hint of what is going on. This may not even be the injectors doing this. The fuel pressure regulator is built into the throttle body and that could be leaking. Try unplugging the injectors and see if the fueling stops then.




78 Corvette Pace Car For Sale-18k mi orig-Florida




(This post was edited by Hammer Time on Sep 27, 2009, 7:33 AM)

I replaced the injectors and still the car is having trouble turning on and once it drives its like its gasping for fuel but I was wondering if it could be the fuel filter instead of th epump since the car is still turning on .

thanx guys

Why did you change the injectors? Nobody ever suggested that. No, the fuel filter won't cause that.




78 Corvette Pace Car For Sale-18k mi orig-Florida

ok ive changed the injectors, fuel filter ,I also tested the fuel pressure an got 8pci's.....? and discovered some vacum leaks but the car is still doing the same thing it will run for about an hour an start to shut off while driving or stopped if you have any suggestions please help. thanx

If your saying that your fuel pressure is 8 PSI, then there is a problem. The spec is 9-13 and I'm sure yours gets even worse at times. Get your fuel pressure resolve first.

You could have a regulator leaking in the throttle body.


The pressure regulator is an integral part of the fuel meter cover, and contains an air chamber and a fuel chamber that are separated by a diaphragm-operated relief valve and a calibrated spring. The function of the regulator is to maintain constant pressure across the injector at all times.fuel pressure is regulated by the difference between fuel pump pressure acting on one side of the diaphragm and the force of the calibrated spring (and air cleaner pressure) acting on the other side. The system operates in an acceptable pressure range of 62 to 90 kPa (9 to 13 psi). The fuel meter cover includes a bleed that relieves system pressure when the engine is turned "OFF". The bleed also helps purge vapors from the injector and regulator after a hot restart.
If the pressure regulator in the TBI supplies pressure which is too low (below 62 kPa or 9 psi), poor performance could result. If the pressure is too high, excess emissions and unpleasant exhaust odor may result.




78 Corvette Pace Car For Sale-18k mi orig-Florida




(This post was edited by Hammer Time on Oct 20, 2009, 7:16 PM)

 yes I got 8psi's and fuel pressure resolve?? could it be the pump ? I went to carx and they said i need a new distributor, erg sensor, and map sensor???

How are any of those things pouring fuel into your throttle body?




78 Corvette Pace Car For Sale-18k mi orig-Florida

they arent, its either the fuel pressure regulator or the pump then right?

The pump isn't going to do that either, especially with the low pressure reading. I would pinch off the return hose or the pressure hose after your gauge and check the pressure again. If it spikes up then, the pump is fine. If you can't get any readings over 15PSI, then the pump may be bad. Otherwise, I'd concentrate on the throttle body where the regulator is.




78 Corvette Pace Car For Sale-18k mi orig-Florida

how do i test to see if its the regulator??

Pinch off the return and see if the pressure bleeds off when shut off. If it does, also pinch off the pressure line before the gauge after shut off to see if it stops the bleeding. If it still bleeds with both lines pinched off, the regulator has to be leaking.




78 Corvette Pace Car For Sale-18k mi orig-Florida

which line is the return line ? or pressure hose? and where do you pinch it off?

should the pump constantly hold pressure after you turn the car off when testing the fuel pressure? because it went back down to zero when i turned the car off

I don't know how your checking fuel pressure if you don't know the pressure line from the return.

The pressue line is the larger one. You want to isolate the tank on both lines.




78 Corvette Pace Car For Sale-18k mi orig-Florida

I tested it going out of the fuel filter to the throttle body

That would be the pressure line.




78 Corvette Pace Car For Sale-18k mi orig-Florida

In Reply To

which is the return line?? and where and how do I pinch it off?? thankyou for you help and patience

OK so ive changed the pressure regulator and the car still is turning off and giving me no starts but with the help of some starting fluid spray or throttle body cleaner she starts up eventually, if you have any advice it would be greatly appreciated..thank you