When I disconnect the timing connector and rev the engine should the timing remain constant or move?
I have checked several cars and one will retard about 6-8 degrees and another one will advance 6-8 degrees, what gives, which one is right?
Anybody have any ideas?

 

With the EST dissconnected the timing will move when you increase the rpm's. That is why you need to set the timing with the car at an idle.

 

Right....so...should it move up or down when you rev it?

 

It should advance.

 

I am confused...

I thought that the computer contained all advance information and relayed ALL timing movement to the dissy via the EST wire. Every time I disconnect it I get no advance with rpm.

 

It does but it still will advance without the computer to keep the car running and to prevent damage. I am not sure how it does it though. Someone will have to school me on the finite functioning of the HEI.

 

oh that could be... maybe like the module has a backup mode when no EST signal is present?

Maybe I just have S*&$%y modules then. I have had many problems with them.

Try posting this on the DIY forum Don. You may get someone to speak up about it.

 

Yes, it is a backup mode built into the ignition module. With the EST connector open the timing should hold steady. As the RPMs increase there should be a sudden advance in timing in the 1,600 to 1,800 RPM range (sometimes as late at 2,000 RPM which is an upper limit of a borderline module).

The distributor that is decreasing in timing as the RPM goes up has something wrong with it.

RBob.

 

Thanks, RBob
That clears it up.

 

I was just wondering about this myself. When I got the car smogged a month ago the Tech said my timing was at 9*. I was getting some pinging so I went to set it back to 6*, When I checked my base timing, est disconnected, it somehow had increased to about 14*. After setting it back to 6*, est disconnected, I thought I might have another problem seeing it jump to about 12* at 1800 rpm. So this is normal for a 92 305TPI?