Fuel Pressure/Injector's Question for ya'll

[DJ SHO]

Anyone ever experience the effects of a fuel pressure regulator on it's last leg? With the help of some SHO folks we've managed to narrow my problem down to the fuel system - bad regulator and possibly one or more leaky injectors.

I re-checked the fuel pressure today. When pump primed it was at 40 psi (normal). After the priming, it dropped to about 31 psi right away. Within 3 minutes, my pressure was down to 0 psi. I know these are the symptoms of either one of the two causes I stated, I've read up on it here. My question is, just out of curiousity, what's the average life of the injectors and regulator?

My whole running condition from the night this whole thing started makes sense now. Either flooding out, or not supplying enough fuel was the reason for the spitting and sputtering. Too much fuel is indicated by my nice red catalytic converters last week. Plus, seeing it's probably more likely the regulator than injectors causing the problem (since all 6 plugs were soaked twice the last two times I pulled them out in the past two weeks), we did happen to get it to "almost" run today with a tiny shot of ether to the TB during cranking. That would indicate that it wants to run, but isn't getting the fuel. And, all my ingniton components check out ok as well as all wiring and grounds.

Any input on past fuel injector or regulator problems would be appreciated. Just curious on your experiences and similar problems with these fuel components. Thanks.

<small>[ July 21, 2003, 12:31 AM: Message edited by: DJ SHO ]</small>

 

[projectSHO89]

Since you have failed the leakdown pressure test, the next step is to follow th procedure in the service manual and to isolate and pinpoint the source of the pressure leak.

The service procedure is specific, it is imporant that you follow it. It will involve disconnecting and plugging fuel lines then monitoring the pressure to see if, for example, the return fuel line or the pump pressure line is causing the bleed down of pressure.

The FPR is easy to check for a gross failure. Just disconnect the vacuum line and check for gas in it. If so, the FPR is leaking. If not, it is may not be the source of your pressure loss.

If the problem is a leay injector, there will be fuel in one or more of the cylinders.

Steve

 

[DJ SHO]

Alright this is totally nuts.

I just went out to check the fuel pressure again. It took me three primes of the pump to get the guage to get up to 40. On third prime, went to 40 and came down to 37. Then I started cranking the engine. The guage dropped and was all over the place. Up and down. Tried a couple more cranks. This time the gauge sat around the 36-38 psi area (fluttering in between those two marks as the engine cranked).

I also inspected the little vacuum line on the regulator. It doesn't have any gas in it.

Doed any of this guage weirdness make sense? It was right after the first crank that the guage smoothed out. During the first one it dropped down right away and then was all over place. And yes, the guage is on tight.

I'm going to borrow my freind's Helms book today and read up on more testing.

I'm getting more and more ****** by the day... cuss headbang cuss rant headbang

<small>[ July 21, 2003, 01:49 PM: Message edited by: DJ SHO ]</small>

 

[masho95]

Are you sure the fuel pressure gauge is accurate? I had the same thing happen on mine before I changed my fuel pump. Took like 5 primes to get the fuel pressure to where it should have been. Changed the fuel pump, and then took another reading while priming the pump a couple of times before starting it for the first time and the guage read 0 the whole time. Started getting worried that I installed it incorrectly or something but the car fired right up. Not sure if I damaged the fuel pressure gauge adapter or the schreader valve connector on the fuel rail. Still haven't been able to get a reading on my barely used fuel pressure gauge! Only used it maybe 5-10 times at the most. So double check the accuracy of the gauge on another car if you can. If you're fuel pressure dropped to 0 within 3 minutes then you're losing pressure somewhere. There's a fuel check valve inside the fuel pump that might not be holding pressure, but I wouldn't think that would be the problem with the symptoms you are showing. Seems like your fuel is leaking into the combustion chamber causing your super rich condition and hard start problem.

 

[DJ SHO]

Yeah I did use guage on two other SHO's yesterday, right after I found out that mine dropped like a ****. One was a 3.0 MTX, and the other an ATX, and both cars showed accurate pressure and held 37 psi for 5 minutes on each car.

 

[Bluto]

Gary,
I still think it may be a fuel pump issue. I know it has been replaced recently but that is why I am suspect to "it" as the problem.
Anyone else think the pump could be bleeding back?

Check your schrader valve for sharp edged, or distorted shape that could cause a bad fit with the adapter. (remember the O-ring?)

You could just have Adam and I supply the gas

<small>[ July 21, 2003, 02:52 PM: Message edited by: Bluto ]</small>

 

[masho95]

I'm seriously doubting it's a fuel pump issue. Obviously if the check valve went bad in the fuel pump the car won't hold fuel pressure, but the car is running super rich like it's getting too much fuel. If the check valve goes bad it doesn't dump excess fuel into the combustion chamber. I don't see how all the injectors start leaking at the same time, but you never know. Do you have a Helms?

 

[DJ SHO]

masho95:
Do you have a Helms?

Yup, just picked it up a little while ago from my buddy's house, along with another fuel regulator, just in case.

 

[TYSHO]

Prime the pump a good 4-5 times quickly and try to start the car up. I have that problem on a 93 and it's the pump.

 

[DJ SHO]

BUMP

 

[masho95]

Ok what exactly does BUMP mean? I've been reading the posts here for a while now and I've never been able to figure it out. Excuse me if I'm being slow.

 

[Frankiek3]

It BUMPS the topic to the top of the forum.
Just so more people see it.

Sorry no input for the problem. shrug

 

[Bluto]

We tested your fuel pressure bout 5 times.
And it fired under a fine mist of eather.
Its got to be fuel!
Bump
Bump
Bump cuss