1989 EFI festiva will run perfect for 30mins to an hour then stall out

[ricko1966]

Just occurred to me do check spark As I already mentioned but if you have spark and you say you have fuel that doesn't mean you have signal to the injectors.When you have your crank no start condition spray some carb cleaner in the intake, if it fires on carb cleaner you need to check for signal to the injectors.I made a noid light for doing this by taking two led bulbs and twisting the legs together.Leds only light with voltage in one direction so you have the positive twisted to the negative of the other one and vice versa,so no matter what polarity your connected in one or the other light will signal.Leds won't damage your ecu and you can use long enough lead wire to hold the lights down with the wiper blades do you can see them from the drivers seat you can even drive and watch for signal to drop.I use T pins to backprobe it into the injectors connector.

[ricko1966]

with it being a automatic trans car maybe their is a problem in the circuit that keeps the car from starting in gear? Try bypassing this circuit so it starts in gear.

That circuit just kills voltage to the starter solenoid and won't shut down a running car.

[Mtnman93]

I did have 12 volts to the coil plug when it quit last time .I know the coil on 1989 is different than any of the other festiva. It does not have an external ballast unless someone has removed it?? 88 has ceramic and 90+ has little plastic one

[Mtnman93]

What would disrupt signal to all injectors at the same time? Also if it was ignition module why will it only start right back if key is turned off then back on?

[Mtnman93]

Very smart idea on LEDs

[Mtnman93]

If it we're coil would it not have to cool down before starting back? It will crank crank crank but if you turn key off then back on it will fire right up. It may die when you give it fuel but will start right back and run anywhere from 5mins to an hour before it does it again

[ricko1966]

I didn't realize it started right back up. just by cycling the key. Hmm. I'll have to think on this one. I have worked on two GM vehicles with a similiar problem 1 astro van one I think it was a Sunbird bot had bare spots on the wiring harness that when they got bumped just right the shorted and shut down the computer. Once the engine was dead and the car was still the short was gone until the next time,and both were shorts where you wouldn't think to look. The sunbirdharness would hit the AC pulley occasionally and the astro van was shorting where the block and bellhousing meet up top and the wires ewere layin on the top. Good luck.

[Mtnman93]

Thanks rico1966 .You seem to always have very good advice on what to check. Your answers always make me think yeah, I probably should have checked that .

[ricko1966]

Now I'm thinking about that stupid sunbird, there was a piece of harness that should have been secured and it was in the plastic tubing and at just the right speed throttle position which way your tongue was pointing etc. it would blow up against the a/c pulley. That being said although not common shorts are not always where you expect to find them. Another good one, a customer had a console mounted cigerette lighter that a penny had fallen in and when things were just right it would blow a fuse and I don't remember what else was on that circuit but that was the complaint, this doesn't work so that's where we kept looking,until like the third visit when we looked harder. .

[Mtnman93]

Ok guys Im pretty sure I have figured out why my car keeps shutting off. Now I need your help finding out why? I checked voltage on wiring coming out of my distributor today and I have 12v on positive (blk/wht) wire and 12v on neg?( Blue wire .whe wyou start the car there is 24v on blue wire!!!! I traced wires down and blk/wht wire has been spliced back into blk/wht wire but blue wire is spliced into ylw/grn wire that runs back in fender beside ylw/green coil wire. I'm assuming someone has wired distributor up wrong but what wire should blue wire off dist connect to?1989 EFI .HELP