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Car History:
CFI removed, distributor changed for a HEI and leaky carburetor installed by previous owner. Everything on this car has/had a serious case of Bubba working on it. I assume nothing about anything on this car until I check it out.
Took the 82 to get a front end alignment after rebuilding it yesterday and the engine runs rough like it's not firing on all cylinders. I replaced the carburetor that was on there with a Holley 4160 600 CFM Vacuum Secondaries and after setting the float levels it runs much better than before but still rough.
I assume I need to first check the HEI distributor cap and rotor for wear, plug wires for shorting and replace the plugs. The previous carburetor ran really rich. What plugs do you recommend for this engine?
I'll add some photos of what I have now in just a bit.
The first thing I checked was the firing order and I found it to be correct according to what I found here with 1, 8, 4, 3, 6, 5, 7, 2 and with 1 being CW by one tower which should not matter.
Like you said, your firing order is correct, but one post further than how the factory runs them. What is your timing set to?
Your vacuum advance is plugged into the Holleys ported vacuum source. The car will run better with this hooked up to a manifold vacuum source, one where you can feel vacuum on at idle.
A new cap and rotor couldn’t hurt. I’m not too well versed in the intricacies of the 1982 computer controlled distributor, but I did find a thread here that talks about how it could be the ignition module.
Like you said, your firing order is correct, but one post further than how the factory runs them. What is your timing set to?
Your vacuum advance is plugged into the Holleys ported vacuum source. The car will run better with this hooked up to a manifold vacuum source, one where you can feel vacuum on at idle.
A new cap and rotor couldn’t hurt. I’m not too well versed in the intricacies of the 1982 computer controlled distributor, but I did find a thread here that talks about how it could be the ignition module.
I've not checked the the timing yet. The computer control stuff is all disconnected AFAIK.
I'll put the vacuum advance on a manifold vacuum and test that, thanks.
Could be a host of things.
Fuel pressure within range for the carb?
If it is the original harmonic balancer, has the outer ring slipped? That will screw up timing.
If that is a new distributor why does it look all beat up?
Rough running at all speeds or only in a certain range?
If that is a spread bore intake, did you use the adapter plate for the carb or just a gasket?
Depending on how long it was running rich the plugs could also be an issue.
Center connector on the cap is the ground. Bad ground = problems. Grab a pair of pliers and gently squeeze the terminal to tighten the connection.
Could be a host of things.
Fuel pressure within range for the carb?
If it is the original harmonic balancer, has the outer ring slipped? That will screw up timing.
If that is a new distributor why does it look all beat up?
Rough running at all speeds or only in a certain range?
If that is a spread bore intake, did you use the adapter plate for the carb or just a gasket?
Depending on how long it was running rich the plugs could also be an issue.
Center connector on the cap is the ground. Bad ground = problems. Grab a pair of pliers and gently squeeze the terminal to tighten the connection.
Fuel pressure is 7psi so yes it's in the range of the Holley.
I've not checked the timing and there is no telling what is original on this car after Bubba got done with it.
It's the distributor that came on the car and probably came out of a junk pile judging from the rest of the things I've found on the car.
Rough running coming home from the alignment shop at 65 for sure and maybe at lower speeds to can't remember now.
The connector is glued to the cap by Bubba!
Check the timing, or we're all just wasting time speculating.
The rusted vacuum advance can on your "new" distributor is a bit suspicious. Hopefully you have a Mity-Vac, and can test that part of the vacuum advance, too (it should work, with a max of 10-12 degrees of advance). Otherwise, you may need an Accel adjustable vacuum advance, too.
There's little I could suggest because it could be so many things but a compression test may be a good place to start.
You can fix that ghetto wiring with this https://www.summitracing.com/parts/msd-8194
Check the timing, or we're all just wasting time speculating.
The rusted vacuum advance can on your "new" distributor is a bit suspicious. Hopefully you have a Mity-Vac, and can test that part of the vacuum advance, too (it should work, with a max of 10-12 degrees of advance). Otherwise, you may need an Accel adjustable vacuum advance, too.
The only thing "new" about that distributor is it's new to me when I got the car... I suspect it came out of Bubba's junk pile just like the carburetor and so many other parts I've replaced on this car.
I do have a vacuum generator and that's how I tested my headlights while fixing them without running the engine.
My timing light is from the 80's so I need to order a new one with the dial...
JT
Last edited by jthornton; Jan 19, 2025 at 12:21 PM.
There's little I could suggest because it could be so many things but a compression test may be a good place to start.
You can fix that ghetto wiring with this https://www.summitracing.com/parts/msd-8194
Thanks for that link!
I can test the compression while the winter blast is going on, it's too cold to open the door and run the engine today. The more I think about it I might have changed the vacuum advance from full manifold vacuum to ported vacuum when I installed the Holley so that would throw timing off I assume. Just need to get longer hose (I cut it off) and hook the advance to the manifold and see.
What is the black part to the right of the ignition module called? I'd just like to replace it and get a new plug. It fell apart when I took the cap off and the black wire going to the red device was not in the correct position and as you can see the two posts are not through the holes. I did manage to take it apart and put the black wire back in the correct place and snap it back together...
I tested the vacuum advance and it works smoothly despite the outward appearance. So when connected to the manifold vacuum it's advanced at idle and when I connected it to the ported it's not advanced when at idle. So that would change my timing...
JT
Last edited by jthornton; Jan 19, 2025 at 01:05 PM.
I may have found the source of the problem, I pulled the plug out after breaking loose the glue and found this mess. I also tested the old Weber carburetor vacuum port that the distributor vacuum advance was connected to and it's straight to the manifold so hooking up to the ported one would make the timing off. Time to order some parts...
My parts came in today, the distributor kit included 3 sets of springs and new arms but I think I'll wait on that until I get a timing light and some msd tape.
Got it back together and ran it a bit and it's running much smoother, not perfect but much better than the ride home from the alignment shop so I'm thinking the ground wire was the issue along with all the shoddy workmanship. It amazing how much is missing on this car and you don't know until you buy a kit and get all the parts that are supposed to be there.
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82 L83 Runs Rough
