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Darin
05-16-2002, 06:30 AM
I finally got around to trying to adjust the vacuum advance on my 89 GW. I was under the impression that there was an alan head adjustment just inside the distributor behind the vacuum module. I can't find a place to adjust anywhere in the distributor.

I finally realized that all my mid throttle hiway pinging is due to vacuum advance. Do all stock distrubutors have the ability to be adjusted? There is a small aluminum tag with numbers attached to the vacuum module part of the dizzy. I can post it this evening if it helps anyone.

From a 400 mile trip last weekend I learned that plugging the vacuum line on the dizzy and the hose to it gives me zero pinging and I can run 87 octane. I would love to get this adjusted correctly. Thanks.

Darin
05-16-2002, 12:44 PM
Can anyone give a suggestion on adjusting vacuum advance?

Langdon
05-16-2002, 02:47 PM
<blockquote>quote:</font><hr>Originally posted by Darin:
Can anyone give a suggestion on adjusting vacuum advance?<hr></blockquote>

The adjusting screw is inside the nipple. IIRC, turning it clockwise will increase advance. Bring the wrench and take the warmed-up truck to a long strecth of uphill hiway with a good shoulder, preferably sloped. Make repeated runs uphill and adjust as necessary. :cool: