i just purchased a msd 6al for my car. installed the box, ran the wiring, and started the car. the car cranked over real hard, almost like the battery was dead. it fired, idled like crap, and would die. now given what i have in the car it doesnt idle very well anyways but it idled and drove great before the install. in order to install i had to disable the ignition module in the distributor and run the magnetic pickup wires to the msd box. that was the only disassemble i did. i drove the car to work after i had the car idling decent, and it would miss above 3500 rpm. as of right now the plugs are fouled out (ac r45ts) and the car is sitting in the garage.

this is what i have...
-Rebuilt L98 350 block 10.5 compression
-Dual 450 holley w/ tunnel ram
-Edelbrock 2204 roller cam (234 int./238 exh at 500, 0.539 int./0.548 exh. lift
-Edelbrock gear drive timing set, Edelbrock Alum heads
-Accel dist and coil
-Edelbrock TES headers no cat Single chamber flowmaster

i had the car tuned pretty good before, no misses or backfires under any conditon. i dont race the car at all. any ideas? would the msd box cause a timing change? i need to get timing tape for my balancer, the timing was set way past the timing mark at idle...i would have to say it was 3-4 inches past the end of the stock mark probably around 12 o'clock on the balancer before it would advance.

im thinking it has to be something with the magnetic pickup going to the msd box. any idea's would be great, except for the ones that tell me i need to go get a new intake/cam setup the only reason i bought the msd box was to improve the issue of the tunnel ram loading the cylinders at idle.

 

Two things here -

First off, I'm sorry to tell you this, but the MSD box isn't going to somehow burn the air/fuel mix more completely than a stock ignition system that's working well. The factory setup (when in proper tune) does a pretty good job without "add-ons".

Be that as it may, that doesn't answer your question, so...

When troubleshooting, the best question to ask (well, 98% of the time anyway) is "What's changed?".

Go back & take a look at all of the connections & wire routing for your new setup - I'd bet you $50 that the problem is caused by one or more of those connections being bad/less-than-100%.

FWIW, a few years ago, I had a problem just like what you're describing, except that I hadn't added anything to the ignition system. Drove myself crazy looking for it, posting questions on boards like this, finally gave up & paid an $80 diagnostic fee for a "stealership" to look at it. Their mechanic couldn't figure it out either!

I finally went over it with a fine-toothed comb, & found that the two-wire harness going from the coil to the distributor had flexed enough over the years to where the two wires were nearly broken in two - but you couldn't see it at ALL until you were right on top of it...

Finally, I'm guessing that you've already spliced wires & such, but just in case you haven't, I figured I'd let you know that MSD makes a plug-in harness for our cars, so that if the box goes bad, you can return the car to stock so that you can still drive it.. That's how I installed my 6AL this last year.

EDIT: Wanted to add a couple things that I remembered just after hitting 'submit' -

First, the MSD box won't change your timing, so you don't need to worry about that. Second, the "loading at idle" problem is likely caused by less-than-optimal jetting on the primary circuits of the carbs you're using. Trying to use the MSD box to address that is applying a band-aid rather than actually fixing it. (No offense!) Good luck with it, the car looks pretty tough!

Hope this helps.

 

well the band aid is exactly what i was shooting for. i really like driving the car the way it is. im going to go through the set up again...i think it could be that i ran the magnetic pickup to close to the rest of the wires in the car. thanks for the great info

 

We had another one of those things crap out here this week, like the man said our cars don't need those add ons...throw it in the trash.

 

The harness only works if you're still using the ECM. With a non-computer distributor, you have to remove the 4 pin module and use the pickup coil as a magnetic trigger for the box.

 

im not using any of the factory harness, pickup is already wired in...

i called msd and accel and we concluded that the coil is the issue. the coil isnt made to handle a CD style ignition. new one on the way

and im not throwing it in the trash, it would be returned way before that.