Hey guys, I have an 83 delta 88 with the 307. I was experiencing some hesitation when the engine was hot. I checked the timing without disconnecting anything, it was 24 degrees btdc. Then i disconnected the four pin connector by the distributor, base advance was only 10 degrees. So I set it to 20 degrees (at 1100 rpm). shut off the engine, and put the connector together.
It immediately had more pep. However, as i feared, there was a very slight pinging. I run regular gas and i know that can cause detonation. Yesterday I turned the timing back to 16 degrees. Less pinging, but still there when the trans goes into third and i'm pushing it. Its barely noticiable but i know it's there because i'm listening for it.
My question is, did I set the timing correctly? and will I possibly damage something from the slight pinging by leaving the timing where it is ?

Thanks in advance for any advice
-Rob

 

Pinging will always cause damage. You can drop the timing down alittle more or try a higher octane fuel.

 

If you are getting pinging at part throttle, check to be sure your EGR is working properly. The EGR cools the mixture at part throttle and the advance curve on the 307 is programmed to take advantage of this.

 

I did some research today. The procedure for setting timing according to the factory service manual is to ground the diagnostic lead on the ALDL under the dash. I was under the impression pulling the four pin connector apart at the distributor had the same effect. So I figured I'd check the timing with the test lead grounded. Turns out the advance was 24 degrees. I had set the advance to 16 degrees using the first method of pulling apart the distributor connector.
So it seems that pulling apart the connector retards the timing 8 degrees more than jumping out that test lead. This gave me a false reading on the base timing.
Anyways, I retarded it back to 20 degrees with test lead grounded. Took it for a short test run and so far so good.

 

Disconnecting the four pin connector disables the computer advance curve and forces the distributor to use the fixed advance curve built into the ignition module. This is the "limp home" mode and is not the same as the grounded ALDL mode that you ultimately used.

 

Thanks for sharing your knowledge, Joe. Out of curiousity, some engines call for that four pin connector to be disconnected to set base timing. Are those engines equipped with a knock sensor (ESC)? I believe the 307 only has EST and I know I don't have a knock sensor

 

The '83 307 Y engine would not have a knock sensor.