MSD 6BTM

[Guest Anonymous]

I have searched archives, so don't flame me. Anyway I purchased a MSD 6BTM(6462) and I need to know how to hook up the trigger wire to the stock 77 fuel injection system. Do I use the mag. pickup wires to the two wires on the distributor or splice the into the distributor wireharness(leaving the computer hooked up) or use the white wire (for points) to the negative wire running to the (coil trigger wire?).

[yo2001]

I'm using the coil trigger wires. But I had to get the tach adapter to crank my car with MSD 6BTM. I got 78 280Z.

[Guest Anonymous]

so I take it you used the white wire to the orig. negative coil wire?

[speeder]

You can use white wire from the neg side of the coil for triggering If you leave the stock ignition box in or hook your distributor's pickup coil into the mag input of the MSD, eliminating the stocker ignition. You will probably need a tach adaptor to provide a compatible ignition pulse input for your injection.

[Guest Anonymous]

Will it preform well, if I use the white wire from the BTM to the neg. coil wire? Anything that will effect it's performance?

[Guest Anonymous]

Do I need a tach adapter for this setup? I am using an autometer tach already, or does the ECU need it to run?

[yo2001]

The ECU needs the pulse to figure out the duty cycle.

 

Man, Rick. I want you to tell me how to hook the MSD box straight to magnetic pick up. My stock ingition set up is crapping out on me. it got me stranded to day. (no spark turn the key oof wait, then spark.) I'm thinking my ignition module is going south on me. Let me know the detail info if you could. Thanks

[speeder]

Getting MSDs to work with the various modifications on Zs can be confusing. I have some experience with this and will keep refining this post until it covers as many of the different combinations as posssible.

 

OK - Here's how I did the MSD6A in my '78:

 

 

I used the magnetic trigger input of the MSD, hooked to the pickup coil of the stock '78 distributor. You have to cut off one end of the MSD-supplied cable and splice it to the pickup wires from the distributor. Connect the green wire from the diz to green on the msd cable, red from the diz to purple on MSD cable.

 

The rest of the MSD6A hookup is per the MSD instructions.

 

Now you need to develop compatible ignition signals for your injection and tach, since this signal on the stock setup comes from the neg terminal of the coil, and the MSD's multiple sparks provide false or no triggering of these devices.

 

I used the MSD 8920 Tach adaptor to trigger the 280Z tach and stock injection - This module gets its input from the MSD's tach output (on the side of the box) and converts the signal to one that will trigger tach and injection. The tach adaptor's output is connected to the wire(s) that previously was on the coil neg terminal feeding the tach/ecu.

 

On one 280Z I saw the tach did not need an adaptor (but did need the resistor removed) for some strange reason - it triggered fine off the coil neg terminal - but this did not work on my cars.

 

One note - you usually have to take out and bypass the resistor in the Tach wire that originally ran from the coil neg terminal to the tach. This thing is located in the wire bundle under the passenger side dash and is a little black doodad about 1/2" X 2" and has two wires connected. Disconnect the two wires and hook them together.

 

Autometer tachs will work straight off the MSD's side tach connector with no adaptor.

 

Here's what we have:

Carbureted with Autometer tach = no adaptor needed.

Stock injection with 280Z tach = adaptor output for tach and injection trigger.

Stock injection with Autometer tach = Adaptor output for injection trigger only.

 

240Z tachs are difficult to make work with an MSD - Most people convert to a 280Z tach. According to Mudge, the MSD 8910HSI adaptor is the one to use for the 240Z tach.

 

I believe this is all relevent for ZX's also - I did the same stuff on my '77

when I was running a ZXT ECCS - don't know too much about ZX tachs, though.

 

This is all valid for any MSD 6 series - A,AL,T,&BTM are the ones I kmow of.

 

Hope this helps - I'll look up wire colors on the MSD and cars for you if you need more info.

[Mudge]

There is a PN for adapting the 240 tach to the MSD, the instructions can be found at ZCar.com , PN is 8910HSI.

[speeder]

Thanks for that Mudge - I edited my post to include the 240Z info. When this discussion thread slacks off, I'll move my above post to a thread of its own.

[Guest Anonymous]

OK, let me get this straight (I feel retarded when talking to the MSD Tech) Use the mag pickup wires (from dist. to MSD box). Then use the Tach adapter from the Tach output on the MSD box to the Tach adapter itself. From there I run the signal wire to the factory negative coil wire (to provide the signal to the ECU). Could some one diagram how they have their car wired. (MSD Tech's don't know much about the Bosch L-Jetronic ignition)

Thanks for all the Help, After I get this sorted out, I will make a wiring diagram and tech artical so this does not come up again.

[speeder]

Diagram here

 

Remember to disconnect the stock ignition box and remove the tach resistor.

 

If you have problems sizing this for printing let me know - I can email it to you.

[yo2001]

Thanks Rick

[speeder]

Yo, rereading your post above, it reminds me of a problem on my 78 that drove me crazy. Sometimes would start right up, sometimes would grind all day and do nothing. Sometimes it would start after several on-off cycles of the key. Nothing consistent.

After going through the ignition multiple times and finding nothing wrong, I then replaced the ignition switch on the back of the column lock. That did it. Turned out that when in the start position there was an intermittant problem with getting voltage to the ignition.

[yo2001]

I thought that was the problem also but this one is different. The car was driving fine all day yesterday and last month or so but last night while it was idling, it just died. I checked for the spark and no spark, I let the car sit for a minute, try again, cranked right up, than 10 sec later, died. It's not the coil or my MSD box because I was getting spark when I turn on the ignition and when I turn the ignition off. My starter turns everytime and my fuel pressure stays up.

 

I think it might be a bad connection on the tach signal wire (stock negative coil wire) and the MSD wire?? I'm going to try to by-pass it like you got and see if that helps. Thanks again Rick

[speeder]

Then there was the other time when the pickup coil in the distibutor was bad - another intermittant that drove me crazy. You might check the continuity of the pickup when in the "not running" condition. ~ 85 ohms is good, open is bad.

[yo2001]

I think you got something there. I'll check on that when my car dies. Thanks

[Guest Anonymous]

Well the car is not running yet, I followed the diagram, the car is not getting fuel or spark. If you hook the coil up to the factory wires then the fuel injection begins working. I need to get this thing on the road....any other ideas? I also bought a tach adapter that was recommended.

[speeder]

Will your car run with the stock ignition setup? If so , then your distributor and coil are good. I would make sure of this first.

 

Then wire it up per the diagram-

 

You can test the added - on ignition system by pulling the plug wire out of the distributor and placing it close to a ground point, then-

 

Disconnect the Mag trigger cable from the MSD. With ignition on, take a jumper wire and short the two conductors of the MSD's Mag input together. You should see sparks jump from the coil wire to ground when repeatedly making and breaking this shorted connection. Along with the spark , you should hear the injectors click every 3rd time you short the pins.

 

 

If this test is good, then your electronics (MSD and Tach adaptor) are working. If there are no sparks, then the MSD is bad or miswired . If there are sparks but no injector signal, then the tach adaptor is the problem.