cregs1119

Ok so I need some help. I have a 78 20r that is only getting spark on the 3rd cylinder. I have put a new cap, rotor, plugs, wires, and switched out the old igniter box and coil with a new hei gm module and coil. I am not sure what to do from here on out aside from reace the distributor itself. I do still have the original igniter box if that changeout is the problem. I just have no idea how to wire it, as the wires were clipped and disconnected before I acquired the truck. Any wisdom or hints would be greatly apprecuated.

crazytexan

iTrader: (1)

did you change the ignitor to the GM at the same time as the cap rotor, and everything else? Was it getting spark to #3 always and thats the cause for all of this? The ignitor is not picky to which cylinder its going to fire on. It just gets the signal from the distributor pick up coil and then fires.

cregs1119

Yes. I changed it all at the same time. The motor had no cap on it when I got it and the original coil and igniter were loose from the truck and distributor. I understand that it is not picky thats why it is so confusing. I spent all afternoon searching online through forums and websites and havent found any help yet.

crazytexan

iTrader: (1)

I would experiment with the Toyota ignitor/coil first to rule out/eliminate possibilities that even total new parts could cause. Yes its very old, but from what I can tell about them is they are very solid and get messed up by human error most of the time. There was a lot of new parts changed at once and you could spend alot more time chasing stuff that's not necessary. What do you mean ignitor and coil were loose? Are they missing or just rolling around in the engine compartment.

cregs1119

The previous owner had cut the wires and the igniter and coil were connected but there was no connection to the distributor.

crazytexan

iTrader: (1)

That's interesting. Well, I would check those important wires to the distributor, and also look into the Toyota ignitor. The GM is an awesome setup, but it gave me so much crap, and it seems to be bothering.g other people as well sometimes which is the motive of my opinion. I'll go take a pick real quick of mine to see if you can re wire it back in.

crazytexan

iTrader: (1)

Dang its gotten cold outside since this evening. Idk how much these will help you, but Longgrey wire is the distrib signal, I hope you have a pig tail on the ignitor you can out some gator clips on for test purposes. Try them either way, but it should only work with them one way.

The black wire with blue connector is a solid ground. That is what killed my spark when I did my rebuild so make sure its a good clean ground.

The coil wires if they still have the small eye connectors on the stock harness are easy to figure out .short one is negative side of coil, long one is coil positive, but you should have those already figured since you got your new coil in there.

And then the factory green connector. Should be it. Your distributor wires SHOULD be the o.ky ones to question. I hope this helps.

cregs1119

Yea. I will get out there and try it tomorrow. I appreciate the help. And you are right about the cold night. Just heard a front is blowing through right now. Texas weather for ya

crazytexan

iTrader: (1)

Just north of San Antonio

cregs1119

Yea. Just south east of Fort Worth here.