No Start

[denguy]

My 91 Festy turns over but won't fire unless I spray in some starting fluid, then it fires right up and runs smooth until the SF runs out. I now have the rear seat folded up and when I turn the key I hear nothing from the fuel pump. Shouldn't it spin up for fuel pressure when I turn the key to the start position?

[jjk1224]

Yes, you should hear the pump prime.

[denguy]

My other Festy, a 92 that runs good, the fuel pump in it makes no pre-start noises. I just charged the battery and tried my down 91 and the damn thing fired right up, ran smooth for about 5 seconds then quit as if I turned the key to off. Relay??? Back to the drawing board. Maybe I'll go back to swapping some parts between the two. I did the ignition modules and that wasn't the problem.

[burnt_toast]

The easiest cheat I saw was the air intake. VAF is a big flapper that sits closed until the engine turns. The computer is waiting for that to open before it turns on fuel. The easy cheap it to pop the airbox lid and with key ON, push the flapper open, simulating that the engine is drawing vacuum. The fuel pump can be heard easily if you're on a quite block.

Also, taking a stethoscope and putting it IN the fuel filler neck while cranking with tell you if the fuel pump is running.
-toast

[denguy]

Like I said, I have 2 Festivas, so I swapped the VAF airbox lids. Both cars repeatedly started and ran perfectly!!!!!! So I re-swapped lids. The bad car started fine a few times then went back to the same no start. So I took the original lid from my good car and put it back on the bad car again and it is still back to not starting. Both lids work fine on my good car. Got all that?? I noticed after it quit, with the key still on, the tach needle randomly bounced up and down a few times. Before, when it running, I jiggled the key pretty good to test the key switch and nothing happened. Could it be the computer??

[burnt_toast]

Intermittent problem...son of a....
Sure it could be the computer. It could be any number of things. Troubleshooting is a pain when it's intermittent. There is a whole lot happening when the engine cranks. I find it very odd that switching the VAF cured the problem temporarily. Corrosion or loose/damaged wires are usually the culprit when a problem is intermittent. Grr. Have you jumped the wires to check the EFI codes? Maybe there's something stored in there that can help narrow it down?

[denguy]

I mentioned my computer because I think they "learn" and adapt themselves, which maybe is the reason the bad car ran good for a bit with the "new" VAF, and then reverted backed to it's faulty ways.
By the way, ever since I've had this car, when first started, even in 90* weather, it would rev to 2200 and then gradually drop to 900 no matter what I tried. The PO had done some added wiring and maybe fried something.