What are the symptoms of an ignition switch that is failing?

[Betis]

I have a 1981 Spider 2000. I am having still issues with the rpm going down to almost zero and going up again when cold. And not always happen. I replaced the Auxiliary valve, TPS, Double relay, spark plugs and cables, afm, wire pick up and ignition module. Also replaced the starter with a gear down from autoricambi. When warm it runs great. What else could be wrong. Running out of ideas. I really hope it is not the ignition switch. It also check the timing and it is spot on. It is idling at about 1050 or so when warm. Checked that on the machine at Wine country motors, the tachometer says 1150 or 1200, not very accurate.
Thanks in advance

[mamsterla]

Since your car is FI, I would look at the Bosch L-Jetronic info on cold start. Based on what you write, the system seems to work fine in closed loop (lambda mode) once the car is warm. The stumbling when cold looks like it may be the cold start valve or related circuit that is used only when the car is not yet warmed up.

I don't have one of these later cars, but have other FI cars so am vaguely familiar with troubleshooting some of the problems. Here is the L-Jetronic reference, but it is not specific to the Fiat implementation:

http://www.cardiagnostics.be/-now/Educa ... Manual.pdf

The specifics for your car are covered really well by Brad Artigue on page 41 of his book on Fiat engines:

https://drive.google.com/file/d/0B5eecl ... Q3TGc/view

[ORFORD2004]

AFM

[Betis]

AFM is rebuilt by Fuel Injection inc, and was tested. So the AFM checked good.

[mamsterla]

AFM is not part of the cold start or warm up circuit. The cold start valve or similar part of the circuit would be more suspect IMO.

[MattVAS]

It is usually one of the three things that operate the cold idle.
* Cold Start Valve - (expensive)
* Thermo-time switch for cold start valve (this literally tells the cold start valve to turn on) - (expensive)
OR (and this is the cheapest and most often forgot)
* Temperature Sensor for the ECU (this is the one that is mounted in the water neck tee between your upper hoses) - (super cheap)

Lastly and I don't exactly know why but I've seen Oxygen Sensors (cheap) be the issue. But when all else failed to fix the issue for other people they did a last effort with an O2 sensor and presto the issue was resolved.

[michaelj]

Mine would need to be jiggled to start the car. It was fine once it was started. But eventually it just died. I went with the Lada unit from AR. Seemed to work ok but suddenly the starter would engage all by itself, AT SPEED. I figured out that the return spring or whatever it is inside the ignition switch would not pull back far enough to the run position. I can turn it a bit more to the left and stop it, but its hell when starting. Well, it just ate my starter and i replaced the starter. I will also be moving the start circuit to a push button. Cant rely on the Soviet junk.

Side note, I was also blowing a lighting fuse all the time. That stopped with the new ignition. Not sure why.