Well my 86 TA diesels sometimes when I shut it off. The engine is not running hot. I went for a short ride yesterday (1-2 miles and it was only in the 30's here) and when I got back to the garage it did it again for a second or 2 and the engine was barely up to temp. It doesn't do it all the time though. What could it be? Please help. Engine is a LG4 carbed 305.

 

the main thing i can think of is if you put 87 octane in instead of 93. also pay attention to the gas you but and dont just buy it because it is the cheapest. feel how the car handles with it. you get what you pay for so to spead. ive been using shell w/ no problems. but when i use other gas my car doesnt seem to like it as much. either way dont ever put 87 in your 3rd gen.

 

I never thought about the gas. Gas would make it diesel? My car hasn't been on the road in 10 years. The last inspection was 2000 when I bought it from the orig owner a few weeks ago. I changed all the fluids but I forgot about the gas I guess. I havn't put any gas in it since I bought it. Maybe a fresh tank of 93 would help! LOL

 

that also makes sense. old gas is not good. but yes ive made the mistake of putting 87 in an old v8 before. but still have issues getting my mom to stay away from doing that in her 88 olds cutlass. i can always tell when she has because it diesels when she turns it off.

 

the most common problem is idle speed too high. other things would be high combustion temps caused by advanced timing, too hot spark plugs, and the low grade fuel.

 

Ok guys thanks for the help! It does idle a little to fast. For some reason the solenoid that the throttle arm rests against won't let it idle below 1000rpm. When I unplug the wire it goes to a nice idle. I think that plus the old gas is the reason it's dieseling.

 

You just solved your own problem. Adjust the solenoid so it controls the idle at the correct speed. When you shut it off, the solenoid will then close the throttle plates all the way. Your current adjustment is allowing the engine to pull fuel past the throttle plates when you shut it off and the heat of the engine is igniting the fuel and the engine continues to run for a few seconds.

 

What is your idle speed (in Park) and ignition timing set at? These are the most common culprits when the engine otherwise seems to run just fine.