OK, I've seen the not so favorable posts about msd-but I have to disagree!!!
We just got back from a 7500mile 'round the country road trip; the car started sputtering and back firing under load only-and a long ways from home!
After scanning it and checking fuel press and everything there looked good I unhooked the msd-and then it wouldn't even start! There was a little spark without the msd, but not enough to even start it with the failed coil!
I installed a new coil without the msd and then it would fire right up-so I rewired the msd again and we were back on the road again.
So the msd kept us from being dead in the road!!!
And yea, it was a great trip, just not enough time.

 

What exactly is it that the box does. I just went out and bought $300 worth of MSD for my trans am. I bought a ready to run distributor and a blaster coil. I didn't get the box, and now when I hooked all the MSD stuff up, my tach doesnt work (nothing to wire it to). I have heard that with the box, you can set a rev limit and other stuff but what exactly does the box do?????

Steve

 

I've never heard anyone bad mouth MSD. Only that an aftermarket ingition setup isn't really needed for most of our setups.

 

The name stands for "Multiple Spark Discharge". Basically, instead of giving one big spark, a MSD box fires off a bunch of sparks one after the other. They start at the same time as a normal ignition, but continue for more degrees of crankshaft rotation, up to a certain RPM at which point there's not time for multiple sparks. There is a way to wire the tach, an adapter cable or something. Check with MSD. I have one, but it's been so long I don't remember how to wire the tach. One nice advantage is that it lets you run a normal plug gap even with a blower. I think it also changes the ignition to a capacitive discharge type which gives higher voltage potential.

 

HI, Sorry I'm not much of a MSD guy. Been more of the Mallory type. I'll be switching over to the MSD as soon as I go forced induction . But to maybe help you with your Tach problem, your tach wire connects to the negative side of the coil. Thats the one that is triggered by the distributer. I belive if memory serves correctly that the tach wire coming from the dash is white I may be mistaken. If MSD tach hookups are different, someone please correct me. I do know thats where it goes for Mallory ignitions. Hope I was able to help

 

Just a side note..

I bought a worn out old msd6 off of ebay for $50.00; it ran for all of about 60 seconds and died out down the road 200 ft from my house. I sent it in to MSD for repair...$15.00 min - $60.00 max, and waited. Just thought I might have wired somthing amiss...never gave it a second thought, just wrote it up to bad luck.

2 weeks later... a brand new MSD6 arrived, in the box with all connectors and documentation...no invoice...no charge.

MSD ROCKS!

 

And oh yeah.... it definately smoothed out the idle!!!!!

 

the gentleman up a few posts was correct. the tach wire is white, and it is in one of the plugs that connects to the stock distributor. Unfortunately, GM uses an in-line filter in series with the tach's so in order to get the MSD ignition output to work you have to find the filter and bypass it. I am still looking for it myself

 

Not on my car (1984 Camaro).

 

I have a 6al box and have no complaints....i would like to get a digital box for more control though. good ignition though

 

I just ordered an MSD-6A for my 1991 Z28 (5.7 TPI L98)......sohuld be hooking it up next spring.....!! Hope it works well....

 

I just sold my 6AL and orderd a 6BTM

 

I gave up trying to find it, I have seen tach filters made by MSD so that you can regain your stock tach functions for sale in jegs and summit, i belive they were around $50. I just went w/ a autometer tach and hooked it straight into the tach wire on the side of the MSD box.

 

Mallory ignition products are the worst products I have ever used in my life...

 

My '89 had no such filter. I hooked the white wire up to the tach output on the box and away I went. When the motor comes up really hard, the tach won't keep up though. It will kinda "bounce" around. My 5" silver Sport-Comp is way more accurate. Just be sure that if you run a box, don't hook up your tach to the coil. MSD says it'll screw up the box, and I have friend who'll vouch for that. Only use the tach output on the side of the box. - Also, as stated, the box fires the plug multiple times per fire, instead of the typical single fire. -

 

it might be important to note though, that the MSD boxes only provide multiple sparks at lower rpms. once you start to build rpm, you get a single spark, but it last longer and is hotter than a regular spark. I forget at exactly what rpm that takes place though

 

on my msd digital 6 plus it stops multiple discharge at 3300rpm

 

ya i think it depends on the model of the box from MSD....if you put it on a scope you can figure out exactly where it happens.

 

I know that using msd's specific harness for our thirdgens, i had no problems at all. My 88 has the small cap hei, i didn't have to change the tach at all, didn't have to cut any wires or add anything, all in all it was the easiest hookup i have done. The tach didn't need any fancy filter or anything, and my tach doesn' "bounce" as some have said. Has anyone else used the harness that they sell?

 

Where did you obtain this harness??? I'm interested in one myself.

Steve

 

I got mine off the shelf at kragen autoparts here in ca but, the part number from msd is MSD-8876. Just put that in on the summit website, at 27.00 it isn't cheap, but sure as hell makes things simple.

 

my msd was the simplest setup in the car, it took longer to wire my cd player up, don't waste your money on a harness.

 

I'm planning on running an autometer tach anyway so I won't even mess with the harness. I also plan on getting the 6AL box so that I don't over rev my engine.

Steve