Test your vafm while cold, then run the truck till its warm and stalls out, then retest the vafm. post results after.

 

I searched and I guess everyone already knows what this acronym stands for. Gee. Air Flow Meter? Where are the leads, and where is the meter/sensor? I searched the forum, but couldn't find a reference to it.

This is 22R, and I see no wired sensor on the intake ducting. variable air flow meter? Is it down under the carb?

 

No VAFM on a '83. Fuel injected trucks only.

Vane/volume air flow meter.

 

Like the Mass Air Flow (MAF) sensor on my TDI.

So I am waiting for a 30440 Mallory promaster coil. low trigger resistance, high energy. And will just put new cap and rotor on it too. Wires looks good, but if I replace them, that's everything. Then I start burning incense and chanting. Maybe wire looms?

 

Hmm.. Interesting problem... Theres only soo much it can be on these carb trucks. Interestingly enough this might be sort of like your problem....

I had an 86 Ford F-150 enter the shop about a week ago with a random "cutting off" issue. Customer stated the the truck just would randomly "quit like someone turned the key off." It was a carbed truck with a brand new engine block so there is not much that could be wrong here. I let the truck run for about 45 mins and then it cut off. Hmmm... interesting seeing how it cut off i knew it was ignition related, because it just quit like it lost rpm signal. After it cut off it would not re-start either which was also part of the customer complaint. First thing i suspected to test was the coil. I hooked up a "dummy" spark plug to the coil wire and sure enough there was no spark from the ignition coil.

Replaced ignition coil and haven't seen the truck since.

 

Kiroshu, I hope you are right. The coil I decided to go with is a Mallory 30440. I has the same overall design as the OEM, but I think the mounting plate is larger. I'll make an adapter plate so it can sit there on the Igniter.

The Mallory 30440 is supposed to have lower resistance, lower trigger threshold, higher voltage, longer duration, and way faster recovery than this application will need. I hope it does the trick. It is supposed to be universal.

 

So now that the ignition system is totally replaced, I moved onto the fuel system. Why would it run until hot, and then stop getting gas? I do not know, but sure enough, a new fuel pump allowed it to run. But there is underlying carb issues that may have contributed.

The idle is variable, and it stalls periodically. Also, it likes to be more advanced than stock setting. Maybe a vacuum issue, or possibly just needs adjusting (and less than ideal compression in the cylinders!). But it is running! And actually, I got some work done with it today, FINALLY! Pulled a yard of paving base on a 5x10 trailer. The idle stabilized and it is running fine. Not bad after 230k miles in nearly 30 years.

$40 for a new Import Direct M22001 OE replacement. Done, for now.

 

Interesting to say the least... I have seen this problem with electrical fuel pumps alot when they warm-up they start to "lock-up" or slow down so to speak due to blockage/wear and tear... but never have i seen that with a mechanical fuel pump.... very interesting... (Noted)

Good find glad you got it fixed.