bad ground connection ?

 

are they rusted inside ?

 

The pick up with magnets inside the distributor was bad in mine. They sent a new pick up out and it still was flaky. I asked for a complete new distributor and it has worked fine ever since. I don't think msd is quite what it used to be.

 

The rust has no effect on if they will trigger the box or not.

I have seen loose connections in the extension cable plugs do this. If you can, eliminate the extension cable and plug the distributor directly to the box. It should fire when you spin the distributor by hand.

Do the regular MSD tests of jumping the purple and green at the connector or intermittently grounding the white wire to be sure the box works.

You can check the trigger coil (and the whole system, box and coil) with a soldering gun. Hold the soldering tip an inch or so from the trigger coil and pull the trigger, the system will fire. Disconnect the coil wire so the engine can't fire or backfire.

The high amperage which heats the tip makes a magnetic field that oscillates at 60 cycles (in the US) and this will trigger the box. This trick works with any variable reluctor trigger using a permanent magnet, Ford, Mopar, GM HEI, etc.

 

The rust has no effect on if they will trigger the box or not.

iron oxide, AKA "rust" inside 2 different MSD 85551 distributors caused spark scatter for me.

MSD has knowledge and acknowledges the issue.


spark scatter will affect correct box trigger effect.

 

Never had an issue with one. Had several, ran on old style 6al all the way to 7al3 no issues. Kinda weird, report back when you figure it out

 

Spin dist with a voltmeter set to AC hooked to the leads and see if you get a reading. You should get an AC signal from the pickup.

 

Ya I do get a reading on both distributors but neither will trigger the msd.

I can hand trigger it and it works fine. I can install a points distributor and it works fine but it will not work with either 85805 even though they are both inside the recommended resistance reading for set by the manufacturer. In both cases the cars were running and just died. No start again.

 

This is where MSD and others are so weak. Tech should be able to tell you that you need X amount of voltage/current going to the box. So if you have X voltage/current its the box, if you don't its either the distributer or the wire between the two.


Since you got two distributers and neither will any longer trigger the MSD box its likely the box is weak and will no longer trigger easily enough...


as said a simple 10 dollar tester with a board powering a blinking light would solve the problem...light blinks distributer good, light no blink distributer no good.

 

Thought I would update this and correct a few things.

One of the distributors has a bad MSD 84661 Magnetic Pickup. It checked completely open. The guy at MSD said he had only seen them go bad when someone had pulled the wires out of the pickup. These wires were still very secure inside the little clamp they have made for it in the distributor. It did not fail due to pulling of wires.

It also has a single piece of one of the reluctor triggers(one cylinder) broken nearly in half (only about half of the reluctor was up near the pickup) which may or may not have something to do with the open mag pickup.
This distributor also had some funk around the area in the bottom of the cap where the shaft runs into the housing. Don't know what that was. The other distributor was fine.

I think it shipped with the bad reluctor and the funk. I couldn't find the broken piece of the reluctor inside the distributor anywhere so..............It should have been there if I did it.

The other distributor was ok.
We found a bad MSD 6AL Magnetic pickup issue with that box because it works fine triggering off the white wire but will not work triggering with the magnetic pickup.

So, I got one distributor working but the other one is going to have to come completely apart to be cleaned and replace the bad reluctor.

Tnx for the help and ideas.

 

We had a pick up coil go bad. Replaced it with a new one. Started but sounded funky. And timing marks were way off with the timing light. We reversed the 2 wires at the box and that fixed it. Double checked the wires where we put the plug on at the distributor end and it is wired right according to the diagram.

 

Also, found out that the Ford 73 to 82 I think it was is the same pickup coil being used in these distributors.
There may even be a Chrysler application that uses the same pickup coil. I didn't find out for sure.
I never had a Ford pickup coil go bad in a Ford distributor so it's got to be a issue with the MSD supplier.
I'm positive of that and I'm working to get the bad pickup coil apart to find out where the problem is. Got to be in the winding. May try to rewind it.

If you use an old pick up coil from a Ford Distributor then you have to grind the two rivets off of the plate area where the bolts go on the MSD pickup and remove the plate.
Make sure you do not put the magnet in the wrong direction. It can go in two different ways. The MSD one is marked with a black mark on the pickup end of the magnet.
The gap between the pickup and reluctor should be between .002 and .003 thousandths. (from memory) A dollar bill is like .004 thou. supposedly.

The digital MSD box Pickup should be installed (wiring wise) in the position that gives the most advance.
The analog MSD box Pickup should be installed (wiring wise) in the position that gives the most retarded position.