I'm working on an 85 GS/GSL 12A RX7. It has two 6A MSD boxes one for leading for one for trailing, both were on the car and working properly. It also has a Mikuni 44 Carb. Both of these items were on the car and working properly before the repair work. I redid the wiring for a few things in the car including the MSD boxes. I wired up the black and orange wires to the coils and the power and ground to the battery. Next I wired up the red and white wires to the leading and trailing ignitors. I double checked and everything appears to be wired properly. The car starts but it runs badly, lots of back fire, propping and when I let off the gas it dies out right away. Any help would be greatly appreciated.

 

Purple and green goes to the magnetic pick up. Thin orange and thin black to coil. Thin red to ignition and White wire is not to be used. And you either ditch the stock igniters or gut it

 

You can also wire it the way you mentioned (black and white inlieu of purple and green) by way of the stock igniters. If i were you, i will check for a bad stock igniter.

 

The thing is everything was running fine before I rewired it, the previous owner did some very poor wiring work and I cleaned it all up throughout the entire car and made everything proper. I will post up the diagram I used to rewire the ignition.

 

This is the exact diagram I used, my colors on my box are the same as one this. Assuming I wired this ignition properly what else could it be? I also reinstalled the carb and replaced the holley red fuel pump with a new one.

 

I believe I did leading as yellow/blue to white and Black/White to Red. Then Trailing behind did Yellow/Green to Red and and Black/white to white. Is this correct?

 

Here is a picture of the engine bay for reference.

 

Anyone have ideas?

 

Check for spark

 

I will double check and get back to you, I cleaned all the plugs that were heavily coated in carbon and did a compression check last night. I am getting a slow and weak crank that I am dealing with now.

 

I am getting no spark from the trailing when I turn it over, only the leading.

 

replace ur traiking igniter. If you dont have extra, re-wire both using the purple and green wire so you dont need the factory igniter..

 

I don't have a purle and green my MSD box has a red and white wire. How do I properly redo the trailing ignitor since I don't have a spare? Also what would cause it to die suddenly after rewiring?

 

How can I test my stock ignitor?

 

Make your own tester based on the attached.

 

How do I go about using the MSD to bypass it?

 

Ditch the igniters and connect the msd's purple and green wires to dizzy. I have to check the writing on my garage wall tonight as i cant remember exactly which dizzy wire they go to.


Found some notes:
Msd green to dizzy red
Msd purple to dizzy green

 

Alright, how do I go about deleting the ignitors? Do I need to open them up?

 

Would you happen to have a wiring diagram I can follow?

 

My goal is to use the working ignitor for the trailing ignition and take the MSD off trailing. Then for now use one MSD box to bypass the ignitor and run leading. Eventually after I get the car running right I will pickup a third coil and take advantage of that second box. For now however when I gut out the ignitor what color wires do I hook where. Instead of purple green my 6A box has a white and red, I want to ensure I don't cross them. Thanks.

 

Okay I rewired the trailing and leading ignition with the MSD and and gutted both ignitors. I found the purple/green wire and got that all working. I confirmed that both leading and trailing have spark. The car runs better however it is still off, bouncing idle and it wants to die. Any suggestions? I played with timing and it didn't help, I can't accuractly set timing with how its idleing

 

You've probly already figured it out, but just in case someone smarter then me, hasn't told you about DMSDDFIS, (Dual MSD Direct Fire Ignition System). I actually did the same thing as you, basically the same damn process! Then stumbled on to that after the fact! I'm running the trailing from the distributor, and both MSD's on the leading, and for the front housing, the other to the rear. It's all firing off three blaster 2 coils. You'll notice that one MSD box can't really keep up at higher rpm's, and if you're boosted, that can cause a huge ping. You'll be saving yourself alot of troubleshooting, and maybe an engine. But you'll also be shooting lightning into your engine!

 

If the ignitors are presumed good I would not gut them as someone could use them. I would open up the dizzy and tap into the pickup wires directly then make a short harness for them coming right off the exit of the stock ignitor mounts (maybe 3-4" of wire with a connector on the end to connect to the MSD harness). Then fill the gap where the j-109 connectors used to be with some water proof silicon or JB Weld.

 

Thanks guys, I ended up rewiring the PO's entire setup and doing it as stated above using the green purple wires on the MSD and running them to the magnetic pickup. Apparently even before the guy brought me his car trailing never worked. Now leading and trailing are working great and he hasn't had any issues with the setup since.