I have a 1986 s10 blazer w/2.8 4x4! I unplugged the tan wire under the glove box to set the timing! anyway I got the timing around 0 degrees and when i plug computer back up, timing jumps to 20 degrees advanced. Is this what it is suppose to do? If not, what would cause it to advance so high? Thanks

 

did you unplug it when the truck was off,crank it,set timing,turn off,plug back in,start back up. Thats how ive always done it. I remember my 1500 truck doing that. everything acted ok.

 

yes i did it just like that but it seems like its a little high for timing! It dosent run real good at start and idle either. I was thinking that the computer my be advancing it to keep it running. If this is the case, is there something i need to check to get it timing better? thanks

 

i used to have a 2.8 what a gutless motor lol nut tough. 0 is wrong, i think its 10deg btc, the tag on the radiator support will say. time w plug unhooked and running, hot and idle. normal to go way adv when pcm takes over dont worry it knows what to do. set as it says to check again after tightening make sure it didnt wander. plug in and test drive, if it pings a little too much under load retard it a tick and drive again. my dist went bad in mine and set to factory spec and had to take a little extra out, like 13 deg btc is where it was happy.

 

My TBI 2.8l says 10 BTDC base timing under the hood and in the chilton manual. With the est connected I idle at about 16 BTDC on a cold start.

 

I have an 87 and 10 BTDC is perfect