HEI Mod problem.....won't run?

[NTJoe]

I have a 92 GS that is giving me fits. When warmed up it runs like a$$ from time to time, RPM's shooting up and bogging when you give it gas. If you shut it off for 5 minutes it will run good for 5-10 minutes then start over again. If its cool out, I might can get home from work (25 miles) without a problem, but going to work in the day when its warm it acts up after about 10-15 minutes. I have run the codes and I am getting almost every code (camshaft position, egr, o2 sensors, VAF sensor, etc). I cleaned the VAF and throttle body and it ran better, but still did the problem.

Anyway, the problem is when I tried to do the HEI mod, the car will not start at all. I have tried with the orange wire attached to the dist and not attached. I used the instructions in the V6 FAQ and it just won't fire. The second I unhook the orange wire from the HEI and reattach it to the dist, it fires right up. I have made sure the HEI has a good ground and all wires are crimped good.

Did I miss something? The HEI was new from Advance.

Thanks in advance for youe help!

[solo_ryder]

Did you rip out the metal prong inside the disty that connects to the old coil? That seems to missing from some FAQ's

That prong has to come out or you will be running the old coil still and not the HEI

[hgallegos915]

X2!

[NTJoe]

Did you rip out the metal prong inside the disty that connects to the old coil? That seems to missing from some FAQ's

That prong has to come out or you will be running the old coil still and not the HEI

I was only doing the HEI mod and not the coil mod. I thought you only disconnected the coil bracket if you did the coil mod too?

[shameem]

Make sure your wiring is correct -
http://www.mx-3.com/phpBB3/viewtopic.php?f=15&t=64723" onclick="window.open(this.href);return false;

For no coil mod - just ignore the coil & 1k resistor mentioned in the writeup and dont cut the 3 wire connector.....

[Nd4SpdSe]

HEI Mod Wiring w/ No External Coil

[NTJoe]

Thanks for the diagram, I was unable to locate that one.

I went out and sure enough they were not hooked up right, so I reinstalled it and it worked. Ran great, but I dont know if it is the source of my RPM jumping as I only let it run for about 20 minutes and went in to take care of other things.

HOWEVER....I went out again later and tried to start it this time it would not start. If I hooked up the orange wire to the dist again then it would start. I know the diagram says it is not necessary to cut the orange wire, but if the ignition module is the problem then it would just continue to give me fits even with the Mod, right?

I am about to lose what little hair I have left. My only thoughts are:

1. The coil is bad...but firing whenever the orange wire is hooked dosent support that.
2. The wiring is bad...but I have double and triple checked the connectors.
3. The HEI module is bad...but I bought it new a couple of months ago.
4. Some other insideous problem is at work that I am unaware of.
5. The ECU may be going out.

I am going to get a new HEI module to try that, but can anyone think of what might be causing my problems?

Either that or I need to find someone interested in buying a CHEAP semi running GS!

Thanks in advance!

[wytbishop]

since the orange wire is the one telling the igniter to ignite, and it only works when you have that wire connected to the dizzy and not the HEI unit...I would suspect the HEI unit.

That was my first thought.

[NTJoe]

since the orange wire is the one telling the igniter to ignite, and it only works when you have that wire connected to the dizzy and not the HEI unit...I would suspect the HEI unit.

That was my first thought.

Well, I got it going finally. My dad reminded me of car that he had that did the same thing and it was a coil. So I did the whole HEI and coil mod and now it runs great. I drove it about 50 miles today and you can tell a difference.

Thanks to everyone for the advise. I appreciate it and this site!

[RX8SE3P]

nd4spdse - So the blue and red wire on the 3 pin connector are NOT cut? They still go to the plug and you are merely adding the red and blue wires to them, which go to the HEI?

My HEI mod STILL does not work and it's giving me the poops!

[wytbishop]

There is a better diagram than this one for cases where an external coil is used. I have it at home. I'll post it tonight.

The Red and Blue wires go from the HEI module to the +ve and -ve coil terminals and then back to the 3 pin plug. On the ZE disty the 3 pin plug isn't actually pluged into anything if you just tap into those wires. I created a harness from the HEI unit to the 3 pin connector with a 3 pin connector from a signal light I think so that I wouldn't have to cut those wires. The Orange wire goes from the HEI module back to the orange wire in the 6 pin plug. If you were using a K8 disty the orange wire must be cut from the 6 pin connector or it will also send a signal to the ignitor in the stock disty which can be a problem if your disty works intermittently. On the ZE disty, you will have to figure out how you're going to plug the 6 pin connector from the MX-3 harness to the 4 pin terminal on the disty. The orange wire will no longer go to the disty at all...so you can pull it from the harness or cut it or whatever you like. I spliced a 4 pin female connector that I got from a Protege disty I think into the 4 wires in the harness that do go to the ZE disty.

I'll make better ZE wiring diagram tonight.

[RX8SE3P]

I'm only really using the HEI by itself, no external coil etc.

I do however have a ZE disty and the correct 4 pin plug for it. So I could give it a shot one day.

For now though, I only want to run the HEI by itself as the orange wire to the 6 pin plug broke right off a the bottom of the plug.

On my 3 pin plug, unlike other people's, my red wire is in the middle. Then there's a a thinner yellow w/ green stripe in the 3rd wire. The 1st wire is a thick blue one.

[wytbishop]

OH...you're just trying to get the stock disty to work with an HEI module...

Extend the orange wire to the HEI module. The red wire from the 3 pin is coil +ve and the blue is coil -ve. Extend them to the appropriate pins on the HEI module without cutting them from the harness. They still need to communicate with the ECU. The yellow is the tach signal wire...you don't have to touch it.

Keep in mind that the reason your disty stopped working may have been the ignitor or the coil...if it's the coil installing the HEI module will not solve your problem. An MSD coil is only like $45. I would do it either way.

[Nd4SpdSe]

Damn, when I posted this it was 8 months ago...Here's my revised diagram for the HEI mod with an external coil...but with a ZE disty, that will change is the wiring for the connector to the disty since it uses a 4-pin rather than the 6-pin



I should make one for a ZE disty.

[RX8SE3P]

OH...you're just trying to get the stock disty to work with an HEI module...

Extend the orange wire to the HEI module. The red wire from the 3 pin is coil +ve and the blue is coil -ve. Extend them to the appropriate pins on the HEI module without cutting them from the harness. They still need to communicate with the ECU. The yellow is the tach signal wire...you don't have to touch it.

Keep in mind that the reason your disty stopped working may have been the ignitor or the coil...if it's the coil installing the HEI module will not solve your problem. An MSD coil is only like $45. I would do it either way.

Yep I have basically routed the red and blue wires away from the plug, which goes into the disty. They not longer go into the disty, they just go from the ECU wiring loom to the HEI. Do they also need to go to the distributor?

Now most of my plugs from the 3 pin connector are also screwed. I thought I might have to get some plugs from another car and start again but I have found that you can actually disconnect the wires from the plug and take out the whole connector. I am going to take all my connectors etc and solder new wires onto them. Then I will be able to use the distributor again and have a much neater way to also wire up the HEI.

Btw the disty was working ok and starting up etc. I just broke the orange wire from the 6 pin plug. That's why I opted to go the HEI.

I'll let you guys know how it goes. I can make a writeup on how to re-wire the plugs from the actual connector if anyone wants.