I've researched throughout different forums before posting here but couldn't find anything exactly as I have. I acquired an 82 pickup that was my grandfather's recently. Truck was sitting for quite some time. Had the truck running great until a few weeks ago.

I have swapped to a Weber 32/26 with a regulator. Complete desmog. Only vacuum line is to the vacuum advance. I have also converted to the GM coil and ignition module after the igniter failed.

Truck runs perfect cold but after gets to operating temp it stalls at a stop and will not idle unless manual choke is half way. Have checked all the fuel lines and filters. Good fuel pressure to the regulator and even tore the brand new carb down to check for trash. Im stumped.

 

Have you checked for vacuum leaks? Even desmogged with the single vacuum line to the distributor, there are a lot of unused vacuum ports that should be capped, & some rubber caps these days have a bad habit of falling off or deteriorating in less than a year.

Are you taking the manual choke off too soon? Are you sure the engine is up to full operating temperate before completely opening the choke?

You didn't mention it but did you ever tune the carb to best lean idle using the idle mixture screw? It sounds like it could be set too lean. Here's a great post about this:
https://www.yotatech.com/forums/f120...2-36-a-240521/

Less likely causes I can think of:
Idle Jet too small for conditions
Distributor timing too far advanced (I once had the distributor hold-down bolt loosen up on me & the distributor advanced itself, so the truck wouldn't stall at warm idle)
Distributor pickup coil failing (engine heat raises the resistance in the coil to the point where it doesn't generate signal)
Failing ignition coil (same problem as the pickup coil)
Wrong or low quality ignition coil, ignition coil primary resistance too high causing damage to module.

I also have the GM HEI Module conversion on my '78 and I use the Standard Motor Parts UC12 coil. It has the right Primary Coil Resistance specs to work with the HEI Module and is of very good quality. When I first did the conversion, I used a cheap Chinese made coil (Spectra Premium C624, also sold under different parts store brand names nut same part number). It didn't even last 6 months. The Primary Coil developed some shorts & the higher resistance took out 2 modules before I could figure out what was going on. High Primary Coil resistance is what usually takes out modules, I learned. I went with the SMP UC12 coil & a fresh module (SMP LX301) and it's been running great with no problems for over 2 years.

Extra Info on HEI conversion - I have found that the distributor pickup coil and ignition coil can look and test fine cold but still be bad, malfunctioning once heated up, as in your situation. I test both with an Ohm Meter and either a hair dryer or heat gun to heat them up & simulate engine heat conditions, & watch the Ohm Meter while they are heating. I've caught a couple of bad pickup coils this way, that went beyond the spec once hot. The resistance spec on pickup coils for all 20R, 22R & 22RE is 130 to 180 Ohms.

 

Chiming in to second what 13swords said, test the resistance of your pickup coil as the factory service manual suggests. My 83 had the same problem of stalling at stops when warm and that was my issue. For me the pickup coil had the proper resistance until my engine warmed up. Once my truck was hot the resistance was out of spec and my problem started. It drove me crazy and Took forever to figure out but the testing procedure is pretty clear in the manual. good luck

 

Think im having the same issue. truck runs great for about 10 minutes, then craps out and starts missing, my new distributor coil pickup is testing 200-210 ohms. I think this might be the cause.

 

If the pickup coil is testing at 200-210 Ohms hot (engine at full operating temperature), that is your likely cause. The cold spec for it is 130-180 Ohms. Over time heat cycling can introduce metal fatigue in the coil wire, creating higher resistance once it gets hot from engine heat. That higher resistance will result in skipped or missing signal pulses to the ignitor (ignition control module) and the coil will misfire or stop firing. After it cools down, resistance drops and it acts normally, until it heats up again.

The only other thing that could act the same way is the Ignition Coil itself. You should also resistance test that, both cold & hot, as a fatigued ignition coil can act the same way. The spec for the '82 ignition coil is:
Primary Resistance - 0.4 to 0.5 Ohms, Secondary Resistance - 8,500 to 11,500 Ohms. If the coil has this problem, you will usually see it on the Secondary side of the readings.
My rule of thumb is anything close to 10% below the upper end on the Secondary reading (cold test) the coil gets replaced. 11,500 Ohms divided by 0.90 (90%) = 10,350 Ohms max reading cold.

If the distributor is original, it may have other wear issues, so it's best to replace the whole distributor, rather than just replacing the pickup coil. There are several available through Rock Auto:
https://www.rockauto.com/en/catalog/...stributor,7108

I recommend the distributor by Cardone. It is brand new (no core charge or returning old parts) & has a limited lifetime warranty. The cheaper units you see on that page either do not have a warranty or only a 1 year warranty. You get what you pay for.
Either way you go, don't forget to check/set the air gap on the pickup coil when installing. The spec is 0.008 to 0.016" (0.2 to 0.4mm). I run my 20R at 0.012", right in the middle and have no issues, even using a GM HEI Ignition Module instead of the stock Ignitor.

 

Thanks, I was reading 200-210 ohms on cold distributor, heated up it was closer to 220. These are on 2 new distributors from LCE

 

210-220 on a cold pickup coil, yep, definitely bad. I still recommend the Cardone distributor from Rock Auto. The stock distributor from LCE is $25 more. Plus their warranty section says they only offer a 90 warranty.

 

I had a similar problem awhile ago. I replaced the battery and the truck ran fine.