I started a thread in the Engine Forum about the lean burn system on my 84 D150 pickup, and the direction of my project has changed so much, I decided to start a new thread in this forum.

Since I began working on my pickup, I have been doing a lot of reading and learning, and I am now in the process of installing the GM HEI system. Due to lack of time to work on it, I took the pickup and the Retrofit How-To article to my mechanic neighbor to wire it up. I went over yesterday to look at it, and it looks to me like he has wired some of it wrong, and it will not fire either. I have drawn a wiring diagram as I understand it, and would appreciate if someone could tell me if it is right. I am not sure if I have all the terminals labeled correctly. Also, what goes to the coil terminals that I have labeled as A and D? (Ground and tachometer maybe?)

I'm working to provide an answer, but need to know if your coil terminal designations are taken from the coil, or if you chose them arbitrarily.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

There are no markings on the coil or anything on the papers that came with it, so I just labeled them arbitrarily. Please point out any errors and I will correct the diagram.

Thanks for your help.
David

Okay. This is a good question; it's hard to find hookup info for this particular coil, but since it's physically a good candidate for the HEI swap, the info ought to be in the article.

I don't have one of these coils in hand, so I can't say for certain, but from what I've been able to dig up, it looks like you need to change some things.

Try hooking up your coil as follows:

A: Should get the wire presently connected to B.
B: Not used, tape off/insulate securely.
C: Not used, tape off/insulate securely.
D: Should get the wire presently connected to C.

So basically you're moving the two connections on the coil over to the "other side". Make sure the coil is well grounded via its housing/mount. Let us know if the car starts!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I will give an update as soon as I feel like working on it.

Right now I have a bad cold or the flu. For 2 days I have been wearing insulated coveralls in my house trying to stay warm without roasting the rest of my family. Now, it is 20* outside, and I am in my shirtsleeves sweating like a horse (not to mention all the coughing and a headache). I probably won't go outside today.

The diagram depicts a coil like the HEI coil I have. My coil has terminals A-B electrically common as are C-D. In the photo The red wire has +12V from the green clip lead and the bracket is grounded. Because terminals A-B are electrically common the HEI module is also supplied with +12V.

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Joshua

I will check to see if they are common on mine. Thanks for the info.

My pickup is finally running . I have been going to work, but I have been feeling so lowsy from being sick, I wasn't doing anything else. My neighbor got it started sometime this week, and yesterday I did a little investigating to see what, if any, variations would work (i.e. common terminals on the coil). If you hook 12 volts to any one of the 4 coil terminals, the other 3 will light a test light, making it appear that all 4 are common, but the truck will only run when wired as stated in the diagram.

I am still using the original carburator with no apparent problems. I have included some pictures of the new ignition system and the carb. The diagram and all of the pictures are clickable links.

Diagram of working system


Close-up view


Mounting position on fender


Front view


Drivers side view


Passenger side view

Good work getting it running. Okay if I put your diagram and external-coil pinout information in the big HEI article? Now you've got the coil wiring all sorted, you may want to brush some liquid electrical tape onto the primary connections. As soon as you can, take that blue vacuum cap off the small vacuum nipple at the base of the passenger side of the carburetor, and run a hose from there to the distributor vacuum advance. And why is the evaporative canister port (larger nipple about halfway up the passenger side of the carb) capped off?

Here is the Holley 1945 operation and rebuild manual (pdf).

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Yes. That is fine with me. I made it a point to note what coil I used at the bottom of the diagram because on my coil A-D are common and B-C are common. Joshie225 pointed out that on his coil A-B are common and C-D are common.

I will.

I had heard or read somewhere to hook up the vacuum advance to the thermostatic vacuuum switch because a cold engine didn't need as much advance as a warm one. That is how I have it connected now. I will change it soon.

That port was not connected to anything and I didn't know what it was supposed to go to. When I started working on the truck, I put that cap on it.


Thanks again for your help and also the carb manual.

Yikes. Not even close to accurate. The thermostatic vacuum switch is for the EGR only, and handles manifold vacuum, not ported. You'll have much better driveability once the vacuum advance is hooked up correctly.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I took my pickup on 3 different test drives from a cold start yesterday. I noticed that it didn't want to run too well for the first couple of minutes, but I thought that was from not having the choke set right. I have moved the line now. I will see how it runs tomorrow.

The ignition system is working great.

I am still using the original Lean Burn carb. As I said earlier, I installed a manual choke on it. In 15* to 30* temps, I have to close the choke all the way, and pump the gas pedal 4 or 5 times for it to start. If I don't do anything after it first starts, it will take 2 or 3 tries to stay running. If I pump the gas a few times after it starts, it will stay running on the first try.
I have tried differrent choke settings after it starts, but it consistently runs slightly rough for 2 or 3 minutes till it starts warming up. Once it is warm, it runs great.

I found what I had read about the vacuum advance hookup (see below). It isn't the way I was remembering. It's to help cool an overheating engine when it is idling. It is out of the loop in normal driving. I have it connected to the carb where Dan said to put it. In only very rare cases will I ever idle for any length of time. There aren't many traffic jams out here in the sticks.

I have posted a question about the heating ductwork on this pickup in the forum titled "Other". Any help would be appreciated.

Coolant Temperature Override

Also referred to as a Temperature Vacuum Switch (TVS) or Thermal Vacuum Valve (TVV). The CTO switch measures coolant temperature, usually from a passage in the intake manifold. It was commonly used starting in the 1960s for switching the vacuum advance from ported vacuum to manifold vacuum at high engine temperatures to promote cooler idling. As emissions controls expanded, it gained many other uses. They commonly have between two and five vacuum ports.

Good!
Kinda. The device you're describing is called a TIC valve, Thermostatic Idle Control. It is an adjunct to a system that ordinarily blocks or delays vacuum to the distributor; the resultant late timing increases the tendency of the engine to overheat, and so the TIC valve was added. Above a certain temperature, it sends full manifold vacuum to the vacuum advance, increasing the engine idle speed (and thus the water pump and fan speed) and cooling down the engine, sorta. This falls into the "hang on and pray" category of cheap emission controls. I can't tell by your description how your vacuum advance is hooked up, but the hose should run directly from carburetor to distributor with no stops in between.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That is the idea I got after I reread it.
Passenger side view


I removed the blue cap and hooked it to that port with no stops as you suggested last week.