Argh!! No spark from distributor. Help!
 

Well, just tried to fire her up for the first time...no spark coming out of the distributor.

I have newly installed an MSD Digital 6, and it doesn't show any signal from the Motorcraft 12127 distributor either (a mag pulse model). When I pulled the coil wire, held it close to ground, and crossed the signal wires from the MSD, I got a good spark to ground.

I called the MDS tech line, and they don't think it is the MSD unit. I tend to agree, as it does look to be working (solid red led when ignition on, no flashing with no apparent signal). The coil also seems ok, so that leaves the supposedly new distributor (came with motor as new, just having been broken in on a dyno, so it should have been working. The problem is, I just don't really know how to troubleshoot these mag impulse distributors...HELP. pleeeese.

Ron,

Maybe ignition switch

Maurice

Is that distributor a points model that's been upgraded? How many wires come from it's sensor? It sounds like your coil and MSD6 are working and it's just a matter of getting a signal from the distributor.

Maurice is right.
Check the "small" red lead going to the MSD box and see if it is getting 12 volts when the key is in the "Start" position (disconnect starter solenoid while doing this). If it isn't check the wiring at the switch and/or replace the switch. Make sure it is out of gear too!

I don't think it was an updated points model. There are two wires coming out of the dizzy...same colors as the MSD wires, with a compatible connector. Was billed as "MDS compatible."

I'll check the voltage later today. As I understand it, this wire is the one that supplies power to the "brains" of the MSD, and powers the red LED on the side of the box that signals it as being "on." This LED does indeed light up, but I cant vouch for the voltage yet.

Check ,with the cap removed , does the rotor go around when cranking the engine over. The pin in the distributor gear can shear, mine just did it again. I have it down to less than an hour. Removing distributor.finding the extra pins , replacing the sheared pin in the distributor gear and shaft , gathering up my tools ,turning crank shaft over to TDC ,and firing up the air compressor ,removing #1 spark plug.blowing in #1 hole to see if both valves are closed, setting distributor ,conecting timing light, and so on. Oh you won't have any oil pressure either.

This may highlight the problem:

The Black/Orange wire from the distributor connects to the Violet wire on the 6' MSD harness, and the Black/Violet from the distributor connects to the Green wire of the MSD harness. It is very easy to believe the Black/Violet connects to the Violet but it is not correct. To verify the condition of the magnetic pickup, check the ohms rating while it is accesable.

http://www.msdignition.com/pdf/tech%...ic_trigger.pdf

Rick and Mike,

Thanks for the input. I'll check when I get off work tomorrow. I've been off line for the last few days...was camping at the monterey historics....must have been 6-7 original cobras, including an original comp 427 car (1 of 19 built), an FIA and USRRC car or two. Also, 2 GT40s. Great show!!

Anyway, keep the suggestions coming. Its frustrating having completed everything, but not being able to start the car after sooo loooong.

Rick,

Thanks for posting the link, but I cannot seem to get it to show. I just get "The page can not be displayed."

What terms did you use in your search? Maybe I can find it another way.

Thanks.

Link
 

Go to "msdignition.com"
at the top click on "Support"
Click on "Trouble Shooting"
on the left click on "Using Magnetic Trigger"


Were you at the Historics Sunday?

Rick,

Thanks. BTW, the ignition switch did go to zero when in the "start" position. Imagin that. Unfortunately, it still wouldn't start once I'd spliced into a supply that had 12v in both the "run" and "start" positions.

I'll continue my trouble-shooting tonight.

Yes, I was at the Historics on Sunday. Left just as the last race started (IMSA GT cars, I believe). Had to get my son home at a reasonable hour to avoid the wrath of mom.

Made pretty good time...3.5 hours to Rocklin, including one gas-bathroom-meal stop.

check
 

Ron,
Take a digital ohm meter and check the 2 wires coming out of the dist.
Disconnect first.
Now rotate the rotor back and forth, the trigger should go from wide open to about 700 ohms when you move the rotor. If it does this your dist is fine.
Good Luck,
Perry.:MECOOL:

Perry,

Thanks, I have lots of troubleshooting to do tonight, so I'll give that a try, and report back tomorrow.

Here's the latest.

First, the dizzy is a motorcraft unit (pn 12127). As far as I can tell, that probably means it was a single point distributor from '72 or later...I guess thats when the motorcraft name came into use. Anyway, it looks to have been rebuilt, with an aftermarket mag pickup installed. The mag pickup wires and connector are identical to those on the MSD digital 6 I installed, but I can't find any reference on the MSD site to any conversion kit.

In testing tonight, the dizzy definitely spins. I definitely have power to the MSD. But I don't seem to be getting a signal. My timing light (non adjustable) doesn't pick anything up. And, when I put my VO meter across the pins, I get a pretty constant 0.615 +/- OHMS of resistance. As I turn the sensor past the reluctor, the resistance drops into the 0.500s, but no lower. I take this to mean that there is no signal being generated. I don't know how far the sensor should be from the reluctor, or even if that is adjustable. And, I'm not sure if there are any other ways to test the functioning of the sensor, but I've considered trying to pull it off the distributor and passing some ferrous metal past to see if I could generate a signal that way.

Any ideas for further testing, or where this retrofit kit may have come from? I looked at the MSD site, and their new billit distributors run $388, and I don't feel like just giving in and spending that kind of cash just yet.

Not sure where to go or what to try next, but it is time to hit the hay.

You have a MSD ignition box so you should use the MSD distributor with part# 8594. It is $286.88 at SUMMIT.

By any chance are your white or violet wires grounded?

Clois

Success, finally!!!

After testing everything that I could think of, I decided to let the pros take over. First, I'd like to thank Tom Lucas at FE Specialties for his help and generosity. After checking everthing that I'd checked, and correcting a few things that I'd done suboptimally :), he figured out that the MSD digital 6 will not send a reliable signal unless the engine is turning above 200 rpm. It just so happens that the McLeod mini starter I was using turns the motor at about that speed. The two are not compatible.

So thats it, I'm on the road as of Friday, but thats another thread.

BTW, Tom was very generous, and I know he didn't charge me for nearly as much time as he had in the car. In that vein, I'd like to thank Maurice L for his numerous hours of help, all of which he gave while only accepting glasses of water and one lunch at Subways.

ps. I did my first real burnout today...priceless.

My pleasure, Ron.

The burn out makes it all worthwhile.

Maurice