Getting ready to do the first tuneup on my 87 T/A. I've done tuneups before but not on the CCC type distributor. What is the standard proceedure to adjust the timeing and at what degrees should it be set at ??? Any other advice or comments would be great. Thanks !!!!
Fakeyankee

 

Don't touch the carb unless you are going to rebuild it completely- or if a previous owner has taken off the tamper-proof seals and fiddled with some of the adjustements. There are no adjustements to play with besides idle speed on a truly stock, factory original CC-Qjet carb. Blasting carb cleaner through the veturis to clean it out some is fair game, however.

There are also no adjustements to the distributor other than to set initial timing. ECM does the rest of the adjustments. Timing is usually either 0* or 6* depending on which engine you have. Either way, 6-8* initial is a decent setting to shoot for.

You have to deactivate the ECM-supplied advance before setting your initial timing. Failure to do so will result in a severely retarded initial advance setting. You have to either unplug the 4-wire ECM connection to the distributor that is located over the tranny bellhousing main wiring harness OR plug a jumper into the A&B ports of the ALDL connector under the dash. The ECM will throw a Check Engine light when you do this, but it will also eliminate any computer-supplied advance so you can set initial timing correctly.

Timing tab is located by looking straight down behind the water pump, in case you were wondering where it was (many people have difficulty finding it).

I would also recommend making a COMPLETE REPLACEMENT OF ALL VACUUM LINES a part of your tune-up, if they are getting old/original. These old computer controlled carb engines have MILES of vacuum lines. They are often seriously cracked, degraded or simply hooked up to the wrong places. Having access to the factory-supplied emissions sticker will give you an diagram of how the vacuum lines are supposed to be routed. If your tag is long gone, post here and somebody will put up a scanned copy for you.

 

Thanks for the reply Damon.
Question; Since I have the LM-1 350 motor and the LG4 emissions system, The books state to have spark plugs for the LG4 heads gapped at .035 whereas the LM-1's gapped at .045. What should I gap them at ???

 

The suggested range is .035" to .045". I run .045" gap on my delcos. I have used .035" gap before, however, did not notice anything different.