So my 89 Auto GXL starts great, runs great, enough power, but after a 10 or so minute drive, it will idle very poorly. It seems to slow dwn and speed up, kinda hunting for an idle. It does not putt along like it should. However, when cold, it idles perfectly.

I do not feel this is a compression problem as the car will warm start fine and doesnt flood. I think it has to do with engine management. Is there a screw I can turn to bump up the idle speed? It has idled low since I got it, and seems to get worse.

Anyways, I feel this may have to deal with spark plugs. I never changed my plugs after doing the ATF trick on my car, I was so amazed that it got my $300 car running I was just happy to be driving it.

Could it be the plugs?
Would this also explain the faint gassy smell to the exhaust under idle?

 

Check the BAC valve.

 

WTF and where is a BAC valve

 

I have your same problem on the same car. Although mines manual... I cant figure it out... Idles funny only when warm and very rich at idle. It also idles low when warm. If adjusting it doesent work then i would say ur oxygen sensor or fuel injectors are dirty. I know mine are dirty.

 

VON...WHAT UP, WHAT UP? CAN YOU EXPLAIN BRIEFLY WHAT FUEL INJECTORS/O2SENSORS ARE??...WHAT THEY DO???...WHAT MODS I CAN MAKE?? AND IF YOU KNOW,,IS THERE A WEBSITE THAT EXPLAINS IN DETAIL??...ANY HELP "GREATLY" APPRECIATED.....-BIG NAP

 

First i would think injectors that do not give a fine spray will not be burned in the cumbustion cycle. Therfor a rich condition at idle. Would also explain how fuel droplets is being sprayed out the exaust pipe. Oh... mabey ignition not firing a rotor u say? Then how *** my plugs looked all alike? So im guessing the injectors... IF not then why not the odygen sensor... Doesent it Cause a rich condition at idle if its not on or worn out. Thats what hapend when i unpluged mine. Now with moding the thing.... Thiers a idle mix screw on the dynamic chamber... thats what i meant. Also the tps will cause a rich idle if misadjusted but i can be wrong? Vacum leak and or bac valve can also be hapening...SO AM I DELERIOUS OR WHAT??????????????

Hey rotorunner.... the bac on the 89-91 is a bypass aircontrol valve that gives extra air to the intake after it senses a load from the a/c and i think headlights.. mabey others but if its stuck or not working i think it can cause ur car to idle funny... Like when i turn on my headlights the idle jumps to 1500 and bounces.. but that might be my tps. The bac is conected to the midle intake manifold close to the top injectors. Its held by two nuts as far as the 89-92s are concerned... I think its spring loaded or something. I saw a spring in their and i think u can spray some carb cleaner or degreaser in it to clean it.. I would rather take mine off. Hope i helped.

 

thanks for the reply

 

you said poop!

out of curiosity, did you figure it out?