1980 200sx 2.2 ohm resister

[brodster]

Jon, I got home late and was drunk so I didn't have time to post anything.

 

I had been thinking about the 3300 RPM stumble all day. I would agree that checking that AFM would be a good thing to do. Do you have a multimeter? You could probe the leads that come out of the AFM that hook up to the AFM. Then you should be able to slowly sweep the AFM by hand and see how the resistance values change. I could look up the exact values or test mine here when I get home, but you should see a smooth transition in values, either decreasing or increasing. In fact, I may do this before dismantling anything to any serious extent. If you have any funky wearing on the track, the ohmmeter should show you this.

 

I had also been thinking about the specific RPM range that this occurs at. The reason I asked you about all the different RPM ranges and loads was to help eliminate culprits. Although the AFM could be the issue, it seems really odd that you are getting the same RPM to be problematic. Somebody correct me on this if I am wrong, but it would seem the AFM would be in different positions, independent of the RPM based on different engine loading conditions.

 

Considering this, it would seem there are only a couple of electrical components that are not RPM independent. The ECU is one, but you said you already swapped the unit with two others. That seems to leave the ignition unit. The dizzy is certainly RPM dependent. It's a long shot but maybe there is some hiccup with the mechanical advance in the dizzy. Even more bizzare, perhaps the hookup (or some problem) is causing a strange resonance at approximately 3300 RPM, which could screw up the timing signals to the ECU.

 

Do you have a timing light? As an easy test, I may watch the timing as you sweep the RPMs. Seems like an easy test that could show you something.

[WAGON JON]

Well, I switched the AFM for another one. The same thing happened. So, I think it is the dizzy. When under load, the engine pings like a mad man! :angry: I had to retard it a bunch and It still pinged! The curve kicks in too fast. I think recurving the dizzy may resolve the problem. I will get back to you on this thought.

[brodster]

Well, I switched the AFM for another one. The same thing happened. So, I think it is the dizzy. When under load, the engine pings like a mad man! :angry: I had to retard it a bunch and It still pinged! The curve kicks in too fast. I think recurving the dizzy may resolve the problem. I will get back to you on this thought.

 

That's interesting. Didn't realize you had another AFM; that's much easier than testing it.

 

Keep us informed of the progress. Good luck!