I was shopping at the wrecking yard for a non-cc distributor awhile back and came up to a van and saw the vacuum canister and decided to grab it. Kind of absent-mindedly cut the wires off below the connector and went. Got it home and realized something wasn't right...it had an extra four wires coming out of it. I did some checking and it turns out it is a 5-pin module distributor. All I can find on the internet is that its rare and a search here came up with one post that said it may be an 81 van I got it out of. Its got mechanical and vacuum advance so I'm sure its non-computer , but does anyone know what the extra four wires go to? I'm sure I can figure out how to put a 4-pin in it but I'm curious what's the story on it.

 

Yes those distributors were used on early 80's vehicles that were carbureted AND computer controlled. Mainly on trucks and some vans. This was when the computer had control of the quadrajet mixture solenoids but timing was left to the distributor. The computers use the pick up coil in the distributor as a crude cam sensor type deal. You should be able to put in a 4 pin module and the corresponding wiring harness w/condensor or aftermarket setup, and run it as an old dizzy.

 

funny you posted this up when you did. i just got finished helping a friend put a new motor in his pickup. his father bought it new back in late 82, so it's history is fully known.
its a 83 1/2 ton with a 305 4 barrel carb. outside of the trans being replaced with a 350 because of constant problems with the original O/D trans starting shortly after the warranty ended, everything is completely factory stock on it. the carb does not have what was called a mixture control solenoid on it, or what it really was on the pickups, a cold start valve, its just a plain old Q-jet.
it has the same dist your talking about, it has the mechanical and vacuum advance, plus timing is also controlled by a minimum function controller, there is also a knock sensor in the block. i don't know how much timing control it had, probably around 10 degrees or so. it does use an EGR valve thats controlled by
nothing other than temperature sensitive valves & throttle opening. the vacuum advance also goes through the temp valves.

 

'84 G20 van here. Originally LG4 4bbl & TH700, has a dealer-installed Goodwrench 350 now. Carb is standard mechanical q-jet, in fact I put on an Edelbrock replacement several years ago.

When we first got the van from my brother-in-law (who had the dealer replace the 305 with the 350), the 4-wire connector had been disconnected and two of the wires were spliced together to bypass the distributor input, apparently. I have no idea who did that or what they intended to accomplish - I know my brother-in-law didn't do it, speculation is a shop did it while trying to figure out why the dying 305 was losing power. I took off the splice and reconnected the computer to the distributor. I know it would run the same with it connected or disconnected when the splice was in there, but will not run with it disconnected without the splice in there.

I don't recall seeing a knock sensor. Guess I'll have to crawl under there again and look for it.

 

AFAIK, those things had a knock sensor and external module to retard timing under detonation.

 

That makes sense.

Wonder if mine still has the 305 sensor and module, then. Wouldn't surprise me, with all the other install errors I've found on it. The invoice didn't show the parts, either.

 

I've got part numbers for the module somewhere. They were a somewhat popular item for retrofitting a few years ago, back when MSD and Carter and whoever were still making things like the Engine Knock Eliminator.

 

found this at the library if anyone is interested. the pins are labelled the same as mine.

http://putfile.com/pic.php?pic=8/22820111455.jpg&s=x1

Is there a ecm involved here anywhere?

five7kid, DENN_SHAH, could you tell me what engine vin code those vans are? thanks.

 

Mine is H.

Still haven't crawled under the van to look for the knock sensor. I'm betting if there, it's the 305 parts.

The ECM is under the driver's seat in my van. Not sure what all it does, TCC lock-up and cruise control, but not sure what else.

 

I'm making some assumptions now.Looking through a Chilton's book, I noticed that in the early 80s v8 vans were generally 8.5:1 compression ratio.Except for a 305 version with 9.2:1. I'm guessing this system was used on those vans to protect from detonation.
I've found it stated that est can retard the spark up to 20 degrees. I'm wondering if these distributors have a more aggressive advance curve built into them. In which case I may need to recurve or get an EST controller.
Anyway I wanted to reply to myself to bump this up and maybe someone would have more input.

 

i don't know for sure what the VIN code is on the truck, but i think its an H also.
he was told by the guy who rebuilt his engine it had the closed chamber heads on it.
i always thought it ran alittle better than most of the other 305 pickups i drove did.

on the trucks, the ESC controler was mounted in the dash to the the left of the glove box if i remember right.
it kind of looks like a small ECM, seems like they are about 4 inches by 4 inches by about 1 inch.
it didn't do anything other than knock retard on the trucks.
what you posted up is for a truck, on the vans i don't know if it does other things or not, so i would say that five7 knows more about them than i do.

 

You don't want anything to do with those EST dist's, purchase a non EST dist and use it, your power and gas mileage will thank you. I had a coworker who did just that on his pickup and his gas mileage and power changed for the better. I also helped my brother in law with a friends truck and he couldn't be happier.