HEI Problem (help, I'm truckless!)

[jtminton]

Thought I'd take advantage of a long weekend and swap out my dizzy for an HEI. Got the HEI from a swapmeet. Put on a new cap and rotor, then put it in. I ran a wire from the Unfused Ign slot on the fusebox, and used the ground strap thingy that was in the old cap instead of running a new ground wire from the coil to the plug. Anyway, got it all hooked up and no spark. I get 12v at to the coil, but no spark at the plug. I went and picked up a new coil, thinking that was the problem. Put it in, hooked it all back up and have the same thing. 12v to at the coil, a good ground, but no spark. What's next?

I have until Monday to get this working, or I have to put the old dizzy back in to get to work. HELP!!

Thanks.

[Mongo]

Ok I don't want to sound like I out to make you look like a fool, but My friend's kid is....
She called me telling me her son was having a similar problem with his nova. I when over to her house and met up with her son and looked thing over after about an half an hour of checking wires fuses I said well lets check the rotor, guess what the thing did not have one lol
I just shook my head and slapped him up side his. I said "I thought you replaced the cap and rotor" He only replaced the cap did not know they had to have a rotor too. sigh... teenagers.....

Anyway check and see if it is there.. lol and if it is check the contact points to see if they are worn...

[Mongo]

Opps never mind...... Did not see that you put a new cap and rotor on....

guess I am the one that sound like the fool.... LOL

[jtminton]

Yeah, it's there.

I got a new one when I got the new cap. And I put it on.

[WRMZ71]

Theres a half moon type looking thing underneath the rotor called the ignition module. Take it out and take it to a part store and have it checked. They run about 15-20 dollars if i remember right. If it checks out alright it could be your pickup coil to. I don't think parts stores check these so its a shot in the dark but they are fairly cheap in the 15-20 dollar range as well. To change these you have to disassemble the distributor shaft to install.

[jtminton]

Originally Posted by WRMZ71

Theres a half moon type looking thing underneath the rotor called the ignition module. Take it out and take it to a part store and have it checked. They run about 15-20 dollars if i remember right. If it checks out alright it could be your pickup coil to. I don't think parts stores check these so its a shot in the dark but they are fairly cheap in the 15-20 dollar range as well. To change these you have to disassemble the distributor shaft to install.

Is the pickup coil a different thing than the coil on top of the cap?

[3 on the tree]

Do you have the 12v going to the correct terminal on the cap, and did you put the coil ends in the correct slots. I have seen people hook up their hot wires to the tach slot-don't work there.

[WRMZ71]

Yes the pickup coil is different. Its wires hook into the the half moon ignition module thing. It should be a white circle thing that goes clear around the distributor shaft in the bottom of the inside of the distributor. You have to take a pin out of the distributor to take it out and install a new one.

[jtminton]

Originally Posted by 3 on the tree

Do you have the 12v going to the correct terminal on the cap, and did you put the coil ends in the correct slots. I have seen people hook up their hot wires to the tach slot-don't work there.

Well, looking at the coil, from the plug side I have a yellow wire off the left side of the coil that goes on the left side plug slot, a black wire coming from the center of the coil that has a loop wire terminal that is hooked to the coil bolt, and a red wire from the right side of the coil that is going into the right plug slot. I have my 12v wire plugged into the right terminal, and the tach wire plugged into the left side.

[jtminton]

Originally Posted by WRMZ71

Take it out and take it to a part store and have it checked.

So if I take it to O'Reillys and ask them to test it are they going to know what I'm talking about?

[WRMZ71]

Not actually looking at mine that sounds backwards. Look at the cap where the wires plug in. It should say tach and bat. Use that as a reference when plugging in your wires.

[WRMZ71]

They should. I don't think i ever took one to oreillys but I've taken them to Napa and autozone and they tested them there.

[jtminton]

Originally Posted by WRMZ71

Not actually looking at mine that sounds backwards. Look at the cap where the wires plug in. It should say tach and bat. Use that as a reference when plugging in your wires.

That's how the dust cover says to wire it. It's also how it SEEMS it should, since it's wired in the same order that it comes out of the coil in. It's also the same way that the pictures on Shifty's 6cyl HEI swap FAQ are wired, and I'm would assume it's the same way for the 350.

But I've been wrong before. . . .

[fastwillie 696969]

did you put back the little contact pin under the coil ?

[jtminton]

So I went and pulled everything back out so I could take the ignition module to go get checked, per WRMZ71's suggestion, and something seems weird.

There are two spade terminals on the left of the module, that plug into the wire harness that goes up to the cap. Then, there are THREE spade terminals, however, the plug that goes to what I assume is the pickup coil only has two slots. What's going on?

The two spade terminals on the harness side have a 'B' on the left, and a 'C' on the right.

The three spade terminals on the pickup coil side say 'H', 'L', and 'D'.

THe code on the module says it's GM and has 308E 3H26 on it.

Did the dude I bought the HEI from put the wrong module in? If no, which two of the three spade terminals do the pickup coil hook up to?

[jhow66]

Module should look like this: 1st picture
Pickup coil looks like this: 2nd picture
Make sure you have this ground strap: 3th picture

[jtminton]

The module that I have has 5 pins. What would that go on? I am going to pick up a new 4-pin one today. Sounds like the guy I got the HEI from just pieced one together.

[WRMZ71]

somebody correct this but I believe the 5 pin connectors started coming out on later model vehicles. Hopefully this is what your problem is and it will be an easy fix for ya

[neonlarry]

^ Yeah I think the 5 pin are on the computer controlled models. Are you sure the HEI you have is not a computer controlled model? Does it have a vacuum can? If not you have a computer model, won't work on our trucks (unless you want to go TPI).

[jtminton]

Went and got the new module today. Put it in, but still have the same problem. 12v at the coil, but no spark. Is there an easy way to test the pickup coil (or the regular coil for that matter)? This is getting depressing. . .

Also, the HEI does have a vacuum canister. The plug setup inside is made for a 4 pin module. I don't know whether the guy somehow made the 5 pin one work, or was just trying to make a swapmeet HEI look better.

[JimKshortstep4x4]

Although it is not a definitive test, you can test the pickup coil with an ohm meter. It should read 750-800 ohms between the two terminals, (it has to be disconnected to test).

Usually when the pickup coils go bad you will get a very high ohm reading as in an open circuit.

Good luck,

Jim

[Hart_Rod]

For around $150, I think you can buy a new distributor at Advanced auto part or AZ. I know thats not what you wanted to hear, but that is the chance you take when you buy used parts. Best of Luck.

Rob

[byrd]

I just pulled my old hei out and did the new one w/ 50,000 volt coil, billet style for $175 at the GM performance dealer here in Louisville. I've got the old one still and has new GM 4 pin module(has about 2000 miles on it) had new aftermarket coil and worked good except the wires from the coil to the internals of the dizzy were knicked and missing insulation, that's what made mine run good one day and bad the next anyway I sill have the old one for parts, and you could gut the parts from mine to use in yours and maybe has a spare part or two. How's $50 shipped sound? The GM module itself cost more than that at the dealer. Randy

[jtminton]

I got up this morning feeling rather depressed about this whole situation, resigned to the fact that I was going to have to put my old dizzy back on and save the HEI project for another day. Went out, pulled all the wires off, took off the cap, and unbolted the HEI. As I started to take it out, I noticed the plug that goes into the cap. I realized that I DIDN'T have to unplug that to take the cap off like I should have needed to. I had never plugged it in after I put in the new module and installed the HEI.

So. . .

I put everything back together, ran the wires and plugged everything back in. Turned the key over, and it fired! Set the timing by ear (I'm stopping by my dad's later to borrow his timing light) and it runs like a dream. In yesterday's 100degree heat, I had neglected to plug the HEI into the cap, which of course meant no spark.

Thanks to everybody who helped point me in the right direction! I learned a valuble lesson, and I hope that I have provided some of you with a little laugh! This is pretty standard jtminton fare as far as auto mechanics go. . .

[Palf70Step]

Glad you found it and got her running. That heat will get to you, I have been know to forget a whole bunch of stuff when working where it is to dang hot.