what would cause timing light to jump?

[tsidrift1]

I have checked my ignition timing to see if that was where my misfire was coming from. It wasnt the problem but I did check it and it seems to jump. It will flash regularly and then every few seconds it will like skip a flash or something. I noticed that the timing jumps on the crank a little too. I have thought maybe this is telling me that somwhere in my ignition i am skipping a spark. I have replaced plugs (at .028), wires, coil is a "new" used one, and the transistor is a "new" used one. It still skips a flash and I still get a slight misfire at idle.

Whats the deal!
Let me know,
Anthony

 

[Old Mitsu Tech]

If you are having misfiring and the timing wandering at the same time, I'd look at the Cam Angle Sensor. CAS. It is what tells it "when" to fire. You can either scope it, or replace with known good component.

Being old and all, I keep an extra in my tool box so I don't have to worry.


Good Luck

 

[90 GSX]

I had to bring this back... My car does this too and I think it has a lot to do with the hesitation issues I've been having.

If you are getting misfires, where is the best place to look? I swapped out the CAS already. Could it be the coil or transistor?

I've noticed the timing is easier to set (ie the timing light works) when the car is warm. When the car is cold, it idles but the timing light barely flashes at all, almost like the spark is too weak to be detected.

 

[DAmotorsports]

Do you have any mods on the engine?

 

[92awddsm]

I had to bring this back... My car does this too and I think it has a lot to do with the hesitation issues I've been having.

If you are getting misfires, where is the best place to look? I swapped out the CAS already. Could it be the coil or transistor?

I've noticed the timing is easier to set (ie the timing light works) when the car is warm. When the car is cold, it idles but the timing light barely flashes at all, almost like the spark is too weak to be detected.

You should only set the timing when the engine is at operating temp, not cold. With it cold and fast idle, the cheaper inductive timing lights sometimes have a problem keeping up with the spark.

 

[90 GSX]

Even warm it jumps around. At idle, if the engine misfires and hear a pop out of the exhaust the timing light doesn't fire or fires way off. I tried changing the CAS with another one I have. Didn't work. Next I will try the power transistor and check the wiring I did to swap to a 91-94 ecu/igntion.