Fuel flow

darkhorse40 · Post by **darkhorse40** » Sun May 09, 2010 7:41 pm

I went to the gas station because the fuel that was in the car when I bought it on Valentines day was almost gone.

After leaving the station two blocks from home, the car died. I assumed it was the fuel filter (old gas finally being flushed through) and I changed it. A five minute job.

Still no engine start. I'm trying to find troubleshooting flow chart, but no luck yet.

Anyone experienced this problem before?

Post by **negusm** » Sun May 09, 2010 7:53 pm

Could be anything from your description.

We're talking a 1987 car, correct? So EFI?

If it is a fuel problem...and the fuel pump is original, I would start heading in that direction.

Any codes?

Could be a TFI module or something else. Why do you think it's a fuel problem?

-Mike

darkhorse40 · Post by **darkhorse40** » Sun May 09, 2010 7:58 pm

Just because the timing coincided with old gas being burned off, and I thought there could be crap floating in the tank that could've got sucked in to the system.

I guess I need a code reader, don't I?

I can hear the pump running, but I guess that I could still hear it and that doesn't mean it works.

TFI stand for...?

Post by **negusm** » Sun May 09, 2010 8:33 pm

Thick Film Ignition module

Controls the spark.

FWIW, you could try cycling the key, listen to the pump turn on and off 5 times and then try to restart and see what happens.

A weak pump might build up enough pressure to get the car started after it has been cycled several times.

If you have a code to read you should have gotten a "check engine" light I think.

I would definitely get a code reader. I picked up a no-nonsense one for $36 on ebay. It was an open box one but worked perfectly. I got another and gave it to my dad.

Or you can go to Advance auto or autozone and they will check codes for free.

-Mike

darkhorse40 · Post by **darkhorse40** » Sun May 09, 2010 8:40 pm

I had already tried cycling the pump, no dice.

If I find I'm not getting spark, I'll test the pump. (And I'll borrow my neighbors code reader.)

capriman86 · Post by **capriman86** » Mon May 10, 2010 12:56 am

On a cool motor, turn the key on then press the schrader valve in and see if you get fuel pressure coming out of it.
Chances are if you "hear" your pump, its working.

For spark, pop out one plug and lay it somewhere in the engine bay safely with the plug wire still attached. Have someone try to start it and watch for the end to spark. That will give you a clue if you have any spark or not.

darkhorse40 · Post by **darkhorse40** » Mon May 10, 2010 2:14 am

Those tests will be first on my list in the morning.

Thanks!

85McLaren · Post by **85McLaren** » Mon May 10, 2010 5:31 pm

I don't advance will test OBD1 computers. Only 96 and (ODB2) I think....

Pull codes first. If that checks out ok -
Buy a fuel pressure guage and put it on the schrader valve. My 88 failed because there is a rubber hose that connects the fuel pump to the metal line coming out of the tankl. The rubber hose split. Therefore I was only getting about 20psi instead of approx 40 psi at the guage since half of the pressure was being 'squirted' right back into the tank itself. In my case - the car ran (barely). You just could not move it as when you put ANY load on it - there wasn't enough fuel for the motor to do anything. But if my hose was split even more, it probably wouldn't start as no fuel pressure would be able to make it to the fuel rail.

Jason

plumkrazy · Post by **plumkrazy** » Tue May 11, 2010 3:11 am

why dont you just take the air inlet tube off and spray some carb cleaner and see if she fires

darkhorse40 · Post by **darkhorse40** » Tue May 25, 2010 1:00 pm

Starting fluid did not work.

So I disconnected the fuel line before the filter and turned the key to the on position several times.

No fuel came out if the line.

Unless someone can tell otherwise, I think it gets narrowed to the fuel pump. The pressure I found at the fuel rails was only residual and now is no longer present.

stangmodifier · Post by **stangmodifier** » Tue May 25, 2010 7:17 pm

just hitting a pothole can trigger the fuel safety/cutoff switch to trip.

Post by **negusm** » Tue May 25, 2010 8:04 pm

stangmodifier wrote:just hitting a pothole can trigger the fuel safety/cutoff switch to trip.

Yes, check this, if you don't hear the pump working. You should hear something when you put the key to the on position.

-Mike

86capri62 · Post by **86capri62** » Wed May 26, 2010 2:21 am

Just for information. Never check fuel pressure by depressing the shrader valve. You would be amazed how much fuel can come out of it under only 2 or 3 PSI and the car will not run. Always use a fuel pressure gauge.

tfs2121 · Post by **tfs2121** » Wed May 26, 2010 4:51 pm

you need to make sure the fuel pump is getting good power and ground before you replace it. make sure the fuel pump inertia shut off switch in the trunk is not set. when you turn the key on make sure the check engine light comes on for about 3 sec then goes out.