Hi again,

good weather in Moscow - time to ride on Camaro, but...

the problem:

in general: ignition timing is not stable at idle and slight acceleration when EST bypass connector is disconnected (timing tuning mode).

Details:

1) EST bypass connector is disconnected.
2) idle at 700-800 rpm
3) chek the timing with timing light - 10 degrees (as on the underhood label)
4) Very slow increase engine speed up to 900 rpm
5) timing instantly JUMPS at 25 degrees
5.1) if I increase speed more and more then timing stays at 25 degrees.
6) Very slow decrease speed down to idle speed (700-800) rpm
7) timing jumps back to 10 degrees.

What it could be? Timing is managed only by ECM if connected in this type of engines (V6, VIN T, 3.1, 1992)

Should it be like that or not? What I should do to eliminate the problem???

Thanks in advance,
Peter.

 

Is the timing mark holding steady at 10 degrees when at idle? If not I would look into replacing the timing chain soon. It has stretched over time and could be causing the mark to jump around.

 

From what I remember, if you speed the engine up, the timing will jump far ahead. Haven't done that lately though; I just check it at idle.

 

YEs it is steady, but when accelerating (ECM is off) timing jumps at 25 degrees!

It is also steady at 25 degrees when acelerating more

 

that's right when ECM is on! but when it is off the timing should be steady