MyShibbyZ28

I finally got to hook up the fuel pressure test thingy majig, and i was wondering if this is a fuel pump problem or a regulator problem.

When i prime it, it jumps up to 50 PSI right away but only jumps to there, and falls to 38 PSI and when it's done priming, it'll drop really fast, i mean to 10 PSI in about a minute. When i try to start it, the pressure will go down a little from 38, to maybe 30, then go to 38 again and stay there while running. I need help here, my car will not start now unless i push on the gas to get it going, and i almost have to floor it to get it to start up.

Injuneer

Sounds like the system is losing pressure too fast on the prime. Could be 1) faulty check valve in the fuel pump, 2) faulty diaphragm in the fuel pressure regulator, 3) leaky injectors.

For the FPR, check the vacuum line for signs of fuel. To check for leaky injectors, pull the rails up and pressure the fuel system, looking for leaks. If both those are good, would point to the fuel pump.

If you actually have to floor it, it means the cylinders are flooded, maybe due to leaky injectors. Putting the pedal on the floor puts it in "clear flood" mode, and significantly reduces injector pulse width.

MyShibbyZ28

Well i don't have to floor it, but i have to rev it to maybe 3k to get it to clear, and i have to hold it there for a couple seconds so it'll start. how do i go about checking the vacuum lines for fuel?

SSmoked

Its the fuel pump, mine does the same thing. I prime it 3 times before i start it and then it hasto crank a little longer then normal. When its warm though it dosint do it.

MyShibbyZ28

See though, i can prime mine all i want, and it still won't hold pressure, i primed it 5 times and not once did it hold the pressure for more then 3 seconds at 38 PSI. if i do prime it that many times, it'll try to start right away for a split second then go back to cranking and have a bogged down slow start. But if i try to start it right after i'm done running it for more then 30 minutes, it'll start right up, but that's if i try RIGHT after. if i let it sit for 5 minutes it'll have a little faster start but still a bogged down slow one.

shoebox

At the intake manifold end, remove the vacuum hose that feeds the f/p regulator. Sniff/check for presence of fuel in the hose.

onthemat

I almost guarentee that you have leaky injectors. My dad has a bonneville that does the same thing. After it sets for a while after is has been running, the only way to get it to start is to press the accelerator. I think this adds the extra air to mix with the fuel in the cylinders. It starts and then sputters until it's cleared out. After that it's fine. If it sits over night it starts fine. I know for a fact that it has leaky injectors and the only reason it hasn't been fixed is because it's the extra car.

Pull up your fuel rail and pressurize the system and see if any injectors are leaking. I bet they are.

MyShibbyZ28

Assuming the thing i have an arrow pointing to (shoebox i stole the picture for reference) with blue lines all around it, is the vacuum hose, then i have a problem. I took that off and sniffed it and felt if it was wet, well it wasn't wet but smelt really bad of gas. Then i started the car, stopped it, then took it off again and this time gas came pooring out. Took the hose off and blew the extra gas out that was in there, and started it back up, thing fired right up, but then started to smoke like mad, but that's a different story. So now i have another question....

Does anyone have a good FPR for sale for my 94? I don't like the price of a new one for $85 big ones.

Here's the picture...

shoebox

Sure looks like a regulator diaphragm rupture.

GM p/n 17091221 for the regulator is ~$70 wholesale and $140 retail.

MyShibbyZ28

I just noticed something on your site shoebox. Why is the 96-97 FPR 35 bucks but the 94-95 is 65? whats the difference and why is the price change so much? is it possible to just buy a 96-97 one and will it work with my 94?

BUBBA

Might as well get an adjustable one if you're going to change it anyway. JMHO.

shoebox

I don't know why the prices are so different. I had not noticed that before. I can't think off the top of my head what would be different to need two different regulators. I wish I could tell you for certain that you could use the cheaper one. Maybe someone else has done this and will add their experience.

MyShibbyZ28

You're kidding...you actually DON'T know something? haha just kidding. Yeah, i would like to know myself, cause i think all of us would rather spend 35 instead of 65 or 140 like the dealer told me.

EDIT: found this site, says it's for 93-97 camaro's. It looks like a stock one but is adjustable. I think i'm going to buy the 35 dollar one and see if it fits...*prays it works*

EDIT AGAIN: here's the site http://www.dougrippie.com/drm/fuel_components.htm

BUBBA

Just a thought: If the one you intend to purchase modifies your stock unit, are the stock components still good? Just a thought, since if they are not, and the new unit requires that they are, then you have just bought yourself nothing. JMHO

MyShibbyZ28

Good point, but if i remember right, the 93-97 camaro's all had the same fuel pump right? therefore making it the same pressure, and almost 99% sure the same regulator. They also had same injectors, the entire fuel delivery system was the same, so why change just one little piece for two years? doesn't make sense to me. I think GM knew they were going to stop with the LT1 pretty soon so for the last two years the part wasn't in such demand, so it was a lower price, but no one really bothered to change the price on the following years.