Help Please, FIAT spider 1981, car stalling at 2000RPM

[antonisorphanou]

hello guys, I am new to this forum and looking forward to talking with you.

I have a 1981 FIAT spider and I have an issue I am trying to resolve.
The car starts o.k. and at moments the idle speed looks fine but mostly it sounds really rough and ready to stall/shut off. In addition when I rev to 2000 RPM the engine shuts down. I can not go beyond 2000 RPM. When I try to drive it and add power to the pedal it stalls and shuts down when I am at about 2000 RPM.

I know it mostly points to the fuel pump and/or the Air Flow Monitor/Sensor unit. Am I right on this? is there anything else I should check besides the fuel pump and the AFM?

appreciate your help on this. I have just gotten a new AFM and plan to install asap.

greetings
Antonis.

[spidernut]

Welcome to the forum. The EFI system has a lot of components that can affect how it runs. It can be a multitude of issues.

1. Start by looking for any air leaks between the AFM and the plenum. Air leaks can cause many, many issues
2. Double check the basics - timing, magnetic pick up, cracks in distributor cap, broken rotor, etc.

If all of that checks out, I highly recommend following this guide for troubleshooting Fiat EFI systems. It will take you step by step through the process. It will allow you to identify the problem fairly quickly.

http://www.njfiats.org/joomla/images/st ... BoschL.pdf

[GeorgeT]

Definitely look at the magnetic pickup wires under the timing advance plate in the distributor. These wires fray over time and as the ignition is advanced the frayed wires will short out.

[rlux4]

I'm a little late chiming in here, but a suggestion if you haven't got it fixed yet: The AFM ceramic where the arm touches can develop worn spots or breaks in the arc that is created over time. Look closely at the arc and see if it shows any signs of this. The area that the arm touches can be changed by moving the arm up or down on its shaft. Just loosen the nut and move it a little (probably up). If you haven't had the cover off the AFM you may need to use a utility knife to break the adhesive loose.
Let us know how it's going with this problem.
Ron

[antonisorphanou]

hello and thank you all for your feedback.
Following your suggestions I was able to eliminate issues in trouble shooting the aforementioned problem.
In the end, the problem narrowed down to two issues:

(1). AFM issue with the fuel pump switch (pump would only run on ignition start position and stop there after) and wear and tear on the AFM arc (that I was only able to visually confirm). Also there was a poor connection on the AFM connector last pin (closer to the cabin). The wiring was so stretched that there was a lot of tension on the last connector pin. It was very loose and shaky
(2). Intermittent fuel pump issue. Fuel pump became very noisy at moments.

I have replaced the AFM , the AFM connector and the fuel pump and the car is now running perfectly. I did not try to fix the old AFM unit (based on your feedback) but that is something I plan to do so that I understand the whole setup.

thank you all for your suggestions and feedback. Mostly appreciated. When more than one issue is there, troubleshooting became tough (add to it my inexperience and you get a nightmare) ...

[Odoyle]

Another possible issue could be the temp sensor at the T-hose connection at the front of the motor. My 83 was suffering from almost exactly what you have described, and I seemed to have fixed it by replacing the sensor, rubber cover, & the 2-pin connector along with about 8 inches of wire. Side story: Before I replaced everything I could rev up the motor, or get it to stall by physically moving the wires up or down.

[antonisorphanou]

great pointer, thanks..will keep that in mind..!