Show of Hands-HOw many people have had an MSD magnetic pickup fail???

[*El Ocho 1*]

Bumping this old thread.....wondering if this is what happened to me.

Stopped at a light & I notice my tach starts to go wild, jumping up & down. (engine was still idling normally at around 850rpms.) Then car just dies. push it to the side of the road & battery was low, so I gave it a jump. Engine would just turn & turn, but wouldn't start up. Figured it was spark, so I checked distributor cap & saw that the rotor & contact points were pretty corroded. So I towed it back home & ordered a new cap & rotor.

Installed them the other day but car still doesn't want to start. cranks, fires a few times & dies again. I saw that the magnetic pick up is a bit rusty, could that be it? Really dont want to order a new MSD 6A box, expecially since I just sold the Cobra, & I'm just repairing it for the new owner (I have to give him a car in good working order. It's the right thing to do).

any help would be appreciated guys. Thank in advance

So I changed the distributor cap & rotor a few days ago. I checked the magnetic pick up, & although it it rusty it was showing 580 ohms. Also checked the ignition controller for spark as per MSD's instructions & I was getting some spark from the coil.

Car started right up again, although it had a slight backfire at around 3000rpms.....

Anyways, yesterday I'm taking it to the storage unit & it suddenly dies on me again. Won't start, just turns & turns, but won't actually crank....

I'm really thinking that it may be the ignition control box that's checking in & out. It's mounted behind the dash, but that whole car is hot as hell & vibrates like crazy.

what do you guys think? I'm going to test everything again in a couple of days, but I wouldn't surprised if everything checks out again.

[Blas]

What is the current charge level of your battery?
What is the output from your alternator and Voltage regulator with the engine at +2500rpm?
Should be around +13.6V.
The MSD unit requires a minimum voltage to operate.
If your charging system is not working correctly and the voltage drops off when driving (ie: fans, lights, etc) the unit will shut down.
A classis failure mode for any mfr's electronics.
I assume you have checked all the power and ground connections for the box.

Also: When installing a new cap and rotor, be sure the connector on the top of the rotor is making good contact with the carbon contact on the cap. Not too much spring tension and not too little. If too little contact pressure, the car will run because the spark will arc to the caps carbon contact. But you will see carbon tracks on the cap. too much spring tension and you will destroy the carbon contact.
Hope this helps,

Blas

[*El Ocho 1*]

Battery ws showing 12.85 volts.

Didn't check alternator output..will do if I can start it again this weekend, but at the time it died again I had no electrical loads going.

all grounds seemed good last time I checked about 2 weeks ago.

[*El Ocho 1*]

Added my original post from a few weeks back to this page for reference.

The fact that my tach started jumping like crazy before it died the 1st time is what leads me to believe that the box may be going bad. I didn't notice the tach this time because I was driving & had my eyes on the road.

[pgermond]

Count me in - mine just failed after 10,000 mi. Having some issues with the new one - may not have the proper air gap. I'll try adjusting it tomorrow a.m. when its cooler.

I should add that I checked the resistance of the old before I changed it out and it was withing the specs

[Gaz64]

Double post, sorry.

[Gaz64]

Originally Posted by pgermond

Count me in - mine just failed after 10,000 mi. Having some issues with the new one - may not have the proper air gap. I'll try adjusting it tomorrow a.m. when its cooler.

I should add that I checked the resistance of the old before I changed it out and it was withing the specs

Did you perform the spark test with a paperclip to prove the mag pickup was faulty?

Did the old mag pickup have the correct value (400-1300 Ohms) although some others now say 400-700 ohms, AND no short to ground on either wire?

Gary

[kevins2]

Mine failed after 9,800 miles. Very high ohms - almost an open circuit. I removed the distributor to replace it. Has anyone ever replaced one without removing the distributor? I've been meaning to check if I can get to the allen screws with the distributor in place. Not an easy road-side repair but would be nice if it can be done.

[pgermond]

Originally Posted by Gaz64

Did you perform the spark test with a paperclip to prove the mag pickup was faulty?

Did the old mag pickup have the correct value (400-1300 Ohms) although some others now say 400-700 ohms, AND no short to ground on either wire?

Gary

I did use the paper clip to prove it was faulty, no shorts, but it did test ok with an ohm meter.... but it was bad.

[*El Ocho 1*]

It looks like my problem was the electronic ignition controller box.

I got another 6A from a forum member & switched it out last weekend. Cobra cranked right up (faster than ever before) & ran well for a good while.

[spdbrake]

My MSD 6AL (PN 6420) died a couple of months ago. Started failing on hot restarts a couple of times then nada. Shock mounts under the dash were intact and external heat not an issue. Age was though as it was 13 yrs old. Using a 30x Loupe I found Tin Whiskers in 3 areas of the PCB.


http://nepp.nasa.gov/whisker/index.html