FC Coil, MSD, Will not Idle...
 

This weekend I installed a FC coil and a used MSD on my FB. I first ran the FC coil using the stock wiring setup just to make sure that if I had a problem, I would know that it was not the coil. The car ran fine. I then installed the MSD.

First a few questions about my setup as I want to make sure I did it right. Since my battery is relocated behind the passenger seat, I mounted the MSD in the former battery location as it seemed like the coolest spot for it anyway.

Since the battery is not close by to tap into, I ran the power to the alternator and the negative to the same spot where the engine is grounded on the lower shock tower.

The coil wiring was straight forward. The other two wires (orange and white I think) had me a little more confused. I ended up connecting the white to the original negative signal to the coil that is no longer being used. The orange I ran to the positive of the secondary coil. Not 100% sure this is correct. No dizzy setup and the previous owner had cut those wires off anyway.

The car fired right up, but was trying to idle at 400 RPM. As soon as I gave it some gas, it would get really smooth and be just fine. I just would not idle. I'm assuming that I need to adjust my timing. However, I did not have my timing light on me at the time and I just want to make sure that my wiring is alright before I start playing with anything else.

Also, all of the links that are posted to download a manual no longer work. Does someone have a working link? Need a manual to adjust my timing. Thanks!

Use the purple and green wires on the MSD to the green and red wires on the distributor with a removed or gutted ignitor. (if it is a electronic dizzy?)

Remove the MSD power wire from the alternator and put it on the battery lug on the back of the starter.

-billy

Interesting. Why is the starter better than the alternator? They both have power when the engine is shut off and there are 0 ohms between the two. In other words, they are electicly the same point.

I have the electronic dizzy. What do you recommend that I remove or gut and why? Why would this be better than running the setup the way MSD recommends? Please explain. Thanks!

doesn't the power from the battery go to the starter first? minus the fusible links...

This is the thread that I used to hook it up, but what I am seeing is different than what that poster was seeing. As I said, I just mant someone to verify this setup before I stat messing with timing.

Still looking for a working link to a manual so that I can adjust my timing.

Guys, simple electronics here. Power does not "go" anywhere. Also, two points with zero ohms between them are the same point electricly. I understand that you are trying to help, but I need some hard facts over opinions please.

Thanks!

Are you asking on how to set your timing?

https://www.rx7club.com/showpost.php...34&postcount=2

Or are you asking for help on advancement and whatnot?

http://www.yawpower.com/pultime.html

i meant the cable* my mistake. i was kind of wondering why he said to put it on the starter. that's all...

I have mine set up through the purple and green wires. Once in a while they come loose from the dizzy, causing a severe power loss and idle drops to around 400ish rpm really crappy, but most of the time it works great. which msd is it?

Due to the fact that you are having issues (so time to try something else :) ) and the alternator can be producing a "dirty" signal. They specifically say to not connect to the alternator in the instructions (page 5):
http://www.msdignition.com/uploadedF...structions.pdf

The ignitor is not needed for the trigger of a MSD box. The instructions state the purple and green are to be connected to the "Magnetic pickup" , again (page 5).

By removing the ignitor you connect directly to the magnetic pickup and not through the "amplifier". In our case the amplifier is the ignitor. removing the ignitor eliminates one more part that can fail at a later date as well.

Read the link Stu posted as well.

-billy

Alright guys, I will try hooking this up to the magnetic pickup. I was concerned that the alternator was possible giving a dirty signal, but I have not seen any evidence of any "clean up" curcuit anywhere else in the car. If that is the case, everywhere has a dirty signal. Please correct me if I am wrong. I can try moving it to the starter, but I am trying to keep wire lengths as short as possible and I will try the purple and green magnetic picup first. Only one change at a time till you find the problem, right?

Anyway, I went back and read that post all the way through as I was using that as a reference to run my wiring and admitedly did not get to the end. This is what I get for not reading ;). I will now ditch the white wire.

Everyone keeps talking about gutting the dizzy, yet I have not seen how to do this. Please can someone explain to me what needs to be removed and what I am soldering where? Any pictures, description, or diagram would be great. Thanks guys. Once I get this ignition noe I will be ready to SC this badboy!

I am not an electrical engineer but from what I understand the "noise" that makes it a dirty signal dissipates the further you get from the alternator. Not real sure, just know I was taught to never use the back of the alternator to get 12V.

-billy

Kind of makes sense if we are talking about lines of induction which can affect signals on other wires. It looks like I am only getting half of the spark though, so I'm sure that is my main problem.

Still looking for some details on how to gut and wire the dizzy though!

Search will bring up some pictures if you like.

If you remove the cap, rotor and metal shield from the top of the dizzy you will see the mag pick ups. Those wires are the Green and Red. If you remove the two screw holding the front ignitor off the dizzy you will see it un-plugs. You can simply cut the wires close to the plug and run those to the purple and green on the MSD. Those wires will go: Green on dizzy to purple on MSD and Red on the dizzy to green on the MSD.

A cleaner way is to gut the ignitor. To do so, remove it from the dizzy. Pry off the back metal cover. Remove everything. Add wires from the small mag pickup connector to the larger two pin connector that the car wire harness goes to. Pretty simple.

A even cleaner way to do this is with a 1980 electronic distributor since it does not have ignitors mounted to the dizzy body. Just a wire harness you can use the wire it up with.

-billy

You are a genius. I like that idea!

Also, the only time I use the white wire is when I ground it. Kill switch for the ignition!

Beautiful! Just what I was looking for. I will be doing the first method now as I am going to be doing a FI engine swap soon, so I do not want to dedicate too much time and effort to this right now.

Thanks for the info!

An even better way exists. File down some male quick disconnects (or find some .110 narrow ones) until they fit snug in the plastic connector. Why go through the hassle of gutting an ignitor (especially a good one) or the bad idea of cutting the plastic connector off the green and red wires? My idea is completely reversible. :)

Stu: I just happen to have a spare good '80 dizzy. It is yours if you want it in trade for that carb you gave me. :) I'll bring it to the meet with me.

I do like Jeff's method. If it were me, I would probably go for the gutted ignitor (a BAD one) just because it looks more stock that way. If you don't have a dead one to gut, then certainly go for the male disconnects.

That is truly a clean way - but I have never been able to get anything to fit without falling out. Tried is a few times.

maybe I suck :)

I used to scarf those up for the IT guys.

I will take it if Stu does not want it.


-billy

mine fall out as i have them that way... it sucks.. and it's been proven that i suck :)

Alright, frustrated here. I must have an issue with reading comprehension, or I'm just used to looking at electrical schematics over verbal descriptions. From reading the above paragraph, this is what I gathered:
1.) Remove the cap rotor and the metal shield. DONE
2.) Look for the mag picups which are connected to green and red wires. FOUND
3.) If you remove the front screws, you will see that it un-plugs, simply cut the wires close to the plug and run those to thethe purple and green on the MSD. HERE IS WHERE I GET CONFUSED., IT SOUNDS LIKE THE PURPOSE OF STEP ONE AND TWO WAS MERELY TO SEE WHICH PINS ON THE CONNECTORS ARE ATTACHED TO THE IN ORDER TO ATTACH THESE TO THE PURPLE AND GREEN ON THE MSD.

Anyway, I removed the stock plug on the harness and soldered together another Mazda connector so that I pluged the MSD purple and green to that connector.

Runs the same as before, sounds like it is only firing every other time and trying to idle at about 400 RPM. I also disconnected the white wire. Where should the red wire paired with the white wire now go? Still have it on the the + of the secondary igniter.

Did I totally mis-understand the instructions? Or, did I do it right and the MSD bad?

Mike,

Should be like this:

- heavy red wire connected to battery (+)
- heavy black wire connected to battery (-) or good chassis ground
- white wire - not connected
- green wire - connected to red wire in distributor (leading pickup-ignitor that was facing radiator)
- purple wire - connected to green wire in distributor (leading pickup-ignitor that was facing radiator)
- smaller red wire - connected to switched 12v. trailing coil (+) works well for this
- orange - connected to leading coil (+)
- smaller black - connected to leading coil (-)

Check to see if that is how you have it connected. Is this a 6A or 6AL model? The 6AL needs some jumpersz clipped, but that is only for the rev limiter.

Kent

BTW: make sure that no other wires are connected to the coil (+) or coil (-) on the 2nd gen coil besides the MSD wires (disconnect the wires that run from the 2nd gen ignitor and ballast resistor).

Ok, thanks! I guess my misunderstanding was that the wires in the distributor facing the radiator were being cut and thus not going to be connected to the wiring harness anymore but simply to the green and purple on the MSD so my solution was to simply use the the stock connector. It sounds like you are saying to tap into those wires and keep them connected to the stock harness (the connector on the front connects to the harness and these are the only two wires on it). So, I need to splice into them, but do not cut them as previously suggested?

6A model, by the way.

Let me try to clear this up. Normally, the green/red wires goes to the leading ignitor (on the inside of the dizzy). The output and power for the ignitor are through the stock harness.

Now in your case:

- You remove the leading ignitor (one facing radiator) and plug the MSD purple/green wires to the red/green wires in the distributor. The stock leading ignitor connector is not connected anymore.

The different options (gutted ignitor, splicing, male disconnects) are just methods of connecting the MSD purple/green wires with the red/green pickup wires in the dizzy.

EDIT: just to be clear. The MSD wires connect to the wires inside the dizzy..not the wiring harness on the car

Like I said, reading comprehension must be off, I just do not understand the terms being used, or both. I sware, I'm not stupid, just confused so thanks for bearing with me. From what I understand you are saying is:
1.) The stock harness stays connected
2.) The stock leading ignitor is no longer connected to the harness
3.) Disconnect the red and green so that it is no longer picking up a signal from the stock leading ignitor.
4.) Conect the red and green to the green and purple. So, the green and purple are picking up the signal from the red and green which is connected to the srock connector and harness.

This is different from what I did today I essentually picked the signal up from the leading ignitor.
If I understood you correctly above, I will try that tomorrow. Please correct me if I am wrong. Sorry, years of doing aircraft wiring in the Airforce, makes it hare for me to think of wiring in words rather thank schematics.

Thanks again!

I think we still have our wires crossed. :) See if this helps. If not, I'll draw something up.

Stating with stock setup.

- unplug harness from leading ignitor. This remains unplugged.
- remove the leading ignitor and stick it in your glovebox for another day
- connect the MSD wires to where the leading ignitor was attached to the dizzy

That should do it. Does that make sense?

EDIT: Maybe this will help.

https://www.rx7club.com/attachment.p...0&d=1136955775

From: https://www.rx7club.com/1st-gen-archive-71/ignition-2gcdfis-diagram-correct-502148/

Ignore the wiring on there that looks like it goes from the stock leading coil to the 2nd gen coil. That is incorrect info.

Yes, I have the above drawing, but the drawing is missing the only part that I am unsure of. The rest I understand. The drawing has question marks where my question lies and the issue I have I guess is with terminology.

What is the ignitor and how is this removed?
Once it is removed, I should be able to connect to the front connector as the stock harness is no longer being connected there, correct?

I think this whole confusion is due to me not know what the ignitor is and thus not removing it.

Okay. I see. The ignitors are the little black boxes on the side of the distributor. The leading is facing towards the radiator and the trailing is facing towards the alternator.

To remove the leading ignitor:
- unplug the harness connector that is on the top of the ignitor
- remove the 2 Phillips screws that go through the ignitor
- pull on the ignitor (outward)

The ignitor will come off. You will see a little connector on the side of the distributor where the ignitor was plugged into. Now, if you go with Jeff20B's approach, you will add the male disconnects to the MSD purple/green wires and you will plug them in to where the leading ignitor was plugged in (side of dizzy). Ypu will have to follow Billy's instructions (remove dizzy cap, rotor, and cover) to see which connection is the red wire and which is the green.

Make sense?

Kent

I see said the blind man. This is why I was not understanding why I could not use the connector as the connector is the igniter. Thanks, I will try this tonight.

sorry to dig up a old thread but its better then posting a new one.....

This is a great post for how to set up msd! my question is can i just disconnect the trailing once this is done? i have a msd 6a and a blaster coil and i dont want to use the trailing at all, no real reason i just want to keep it simple.

Correct me if im wrong but the tach draws from the trailing, where can i hitch this to if i remove the coil?

I have also read about people "pinning" the distributor once they put msd on, are they getting rid of just the vacuum advance or both vacuum and mechanical advance?

Thanks guys

Just move the tach connection to the leading coil and you'll be fine.

Folks usually pin the dizzy in boosted applications so they don't get unexoected
advanced timing which could be deadly to a boosted engine.

I currently have my vacume advance hitched to the port in the side of the rb manifold is this wrong? Can I just leave the vacuum advance disconected or will that leave me with timing problems?