1981 rough idle once warm
Thread Starter
Heel & Toe
Joined: Dec 2020
Posts: 22
Likes: 11
1981 rough idle once warm
1981, stock computer and carb. Accel aftermarket HEI.
Car starts smoothly when cold (and the choke light comes on) and runs smoothly after the choke light goes off. But not long after the choke light goes off - minute or two... car starts idling rough. You think it's going to die but it doesn't. Whole car shakes, almost sounds like it has a cam in it. Car doesn't miss or stumble when you accelerate.
Any ideas? I'm thinking vacuum related, pretty sure everything under the hood is stock other than the Accel HEI or whatever it is. Just seems weird it runs ok until it gets warm. I'm used to the opposite! I do have a small exhaust leak, could it affect just the warm idle that badly?
Car starts smoothly when cold (and the choke light comes on) and runs smoothly after the choke light goes off. But not long after the choke light goes off - minute or two... car starts idling rough. You think it's going to die but it doesn't. Whole car shakes, almost sounds like it has a cam in it. Car doesn't miss or stumble when you accelerate.
Any ideas? I'm thinking vacuum related, pretty sure everything under the hood is stock other than the Accel HEI or whatever it is. Just seems weird it runs ok until it gets warm. I'm used to the opposite! I do have a small exhaust leak, could it affect just the warm idle that badly?
Racer
Joined: Apr 2019
Posts: 300
Likes: 83
I have a 81 also but my engine has been striped no computer no blower and all that added junk. so with that being said there is no 1 answer, carb may need cleaning, plug wires , plugs may need changing, filter going to carb may be dirty,
Pro
Joined: Nov 2014
Posts: 503
Likes: 66
From: Florida
I have an 81 too, as already said many things to start checking. Mine still has the computer, I rebuilt all mechanicals to stock settings and it runs great. The computer and computer items will run great if you check the basics and start resetting everything to stock settings. First check for vacuum leaks, then timing, electrical items, and if the carb has ever been rebuilt. If the carb needs rebuilt do it yourself will require a few special tools to set up the carb correctly. Also will require a scan tool something similar to a OTC Monitor 85. If you need parts for the carb or want to send it out, contact Cliffs Performance and join his discussion group. He is a Rochester guru and understands the computer carbs. He got me on the right track to rebuilding mine after a local carb rebuilder tried to rebuild 12 times and failed.
If have not already done so I would recommend buying the 1981 shop manual and assembly manual. Those will be your best resource and tools in your tool box, lots of information and diagnostic test scenarios.
Good Luck
If have not already done so I would recommend buying the 1981 shop manual and assembly manual. Those will be your best resource and tools in your tool box, lots of information and diagnostic test scenarios.
Good Luck
Last edited by Reaper19; Jan 24, 2021 at 09:32 AM.
