Car won't stay running.

[Nicola]

I got my 1982 FI fiat home and it was running for the first 200 miles I put on the car. Then one morning it refused to turn over.

So I replaced the following:

Fuel Pump
Fuel Filter
Fuel Injectors
Battery
Coil
Spark Plugs
Spark Plug Wires
Air Filter

I also redid all the grounds on the car.

Now it will start up no problem, but it will only idle for about 30 - 45 seconds then stall out. I am at a loss for what else could be the issue as I have replaced most of the critical parts.

[So Cal Mark]

were any of those parts tested and found faulty? Throwing a box of parts at the car won't solve the problem unless you get lucky and one of those parts had failed. If it only runs for 30 seconds, it's probably only running on the cold start injector. You're going to have to get the FI troubleshooting manual and do some diagnosis

[Nicola]

I did have the old parts tested after I replaced them.

Here is the rundown:


Fuel Pump - Old one was putting out about 1/2 pressure. (Original factory part.)

Fuel Filter - Old one was a bit clogged (Original factory part.)

Fuel Injectors - Old ones were stuck open. So when I would stop the engine the residual fuel pressure would dump into the
engine. (Original factory parts)

Battery - Old one was still good, but quite old. It was roughly 5 years old.

Coil - Old one was still good. (Original factory part.) I figured it is best to keep the replacement on since the original is 30+ years old.

Spark Plugs - The old ones were still okay, but they too were old.

Spark Plug Wires - Old ones had visible cracking on the wire casing.

Air Filter - Old one was quite dirty.

[wikkid]

Borrow a Noid light set from an auto parts store to test for intermittent signal to injectors. It does sound as if your cold start injector is running the car, and the 4 regular injectors are not doing their job.

When you had the original "no start" problem, can you describe in more detail how it did not start? Good cranking but no firing? Started firing but never really fully "took?" Or other?

[Nicola]

Borrow a Noid light set from an auto parts store to test for intermittent signal to injectors. It does sound as if your cold start injector is running the car, and the 4 regular injectors are not doing their job.

When you had the original "no start" problem, can you describe in more detail how it did not start? Good cranking but no firing? Started firing but never really fully "took?" Or other?

With the original no start problem it would just keep cranking. Sometimes it would sputter once or twice but that is it.

[rlux4]

The three things you need to have a running engine are fuel, spark, and compression. Diagnosing a non start problem needs to address each one of these. Spark; are you getting it at the plugs? Is it timed correctly? Fuel; needs to be at around 35-38 lbs. and needs to be delivered by the injectors. You can check fuel pressure with a gauge on the line going up to the cold start valve. The noid light wikkid mentioned will be the best way to test if your injectors are getting pulse signal. And compression; could be affected by different things, but checking valve timing is a good idea. You need to be sure there are no air leaks in the intake system. Check your boot, auxilliary air branch line and the intake plenum.
Some of this may be elemental to you, but we don't know what you've checked and found to be OK.
Ron

[spider82matt]

On a limb here but I had a similar issue once. After I replaced the heater valve. Upon further inspection while standing on my head I inadvertently had half unplugged the ecu. Then the injectors would only work with the key cranking then shut down. Double check ecu connecter below glove box. Just a thought....

[chuckcloutier]

My 81 had a bad ignition switch that caused stalls and no start situations. All better now!