Stalled and won't start

[Josh_H]

Would someone please help the newbe. I have a 91 SHO with about 150,000 on it. I was backing out of the drive yesterday and it stalled and wouldn't start again. At first I though it was out of gas so I put some more in and tried to start it with starting fluid. It would start and run off of the starting fluid, but barely, and die when we quit spraying. What I know so far is:

* the fuel pump comes on when I turn the key
* some fuel comes out of the pressure releif valve. A small amount will squirt up about 2". I am not sure how much pressure there is but it doesn't seem like enough.
* Pulled a spark plug and held it to the block and there is no spark on that one.
* the tach works when I crank the engine.

I can't imaging that both the fuel pump and a module went out at the same time, so I am guessing a module. From my reseach I am leaning towards the CID(Camshaft/Cylinder Identification Sensor). So my questions are:
* Does that sound right?
* How can I test it?
* Where is it?
* How/where do I check fuel pump pressure?
* Can it be a fuel filter problem?
* If it is a fuel pump problem, why no spark?

 

[projectSHO89]

Sounds like a fuel delivery problem.

Since you state that the FP runs when the key is switched on, that likely eliminates the electrical side of the fuel delivery system, including the inertial switch. Make sure it runs for 1-2 seconds when the key is first tuned to RUN. Do this several times before hitting START. This can help bring up fuel pressure in a marginal system

Under normal conditions, fuel pressure should be 39 psi +/-2. Sounds like you have very little or it all bled off before you release the pin on the valve.

AutoZone sells fuel pressure testers for 40 bucks. They hook up the the Schraeder valve on the top of the fuel rail. A 2" squirt of fuel indicates an extremely low fuel pressure. As 39 psi, you would likely have a gasoline shower unless you are careful. That would point me to the fuel filter as a first step. They are inexpensive and are relatively easy (but messy) to replace. Instructions for replacing them are at www.shotimes.com under "Care and Feeding". If the gas tank was extremely low, you might have picked up enough crap from the bottom of the tank to clog the sock around the pickup. Not fun to replace.

The cam sensor can be disconnected and left unplugged for diagostic purposes. It may take from 1 to 5 attempts to start, but once it does it will run fine.

Try to get your fuel pressure up, then return to the spark issue. It might just be a matter of how the test was performed.

Steve

<small>[ October 27, 2002, 11:31 AM: Message edited by: projectSHO89 ]</small>

 

[Josh_H]

Man are you good. I did as you said and turned the key to run the pump about ten times and then tried to start it and it fired up. We tried it again and it it didn't start that time. But we do know it will run. I will replace the fuel filter and fuel pump and see what happens.

While reading about fuel pumps some have talked about using an aftermarket pump that has a higher pressure. This car is not drove hard and I am not interesting in increasing the performance, so is a stock good enough or will an aftermarket be better? If you suggest an aftermarket pump, which one should I get?

 

[RI-SHO]

Cant beat this price: http://www.autoperformanceengineering.com/html/fuelpump.html#application only $83 for a Walboro 190lph fuel pump, I ordered mine soon to be replaced pmp from there.

<small>[ October 27, 2002, 02:31 PM: Message edited by: RI-SHO ]</small>

 

[projectSHO89]

Just so you know, pumps are rated by how much fuel volume that they can push, hence the lph (liters per hour).

The pressure is regulated by the fuel pressure regulator (FPR) at the OUTLET of the fuel rail. It acts like a dam on a river, ensuring that an adequate pressure is maintained behind it and permitting any excess fuel to return to the tank just like a spillway on the dam allows excess water to go around/over.

Let us know if it's just the filter.

Hope so.

Steve

 

[Josh_H]

I changed the fuel filter and turned the key several times to build up the pressure and the car started. It has been starting today now. I still think the fuel pressure is low, so I will buy a fuel pressure testing tomorrow and check it. I had bought a Airtex fuel pump at the local auto parts store for $80. Should I take that back and order a different (better) one? Or is this one just as good as the one RI-SHO mentioned? This pump does not list the lph.