Need help, no spark!

-
MD68

MD68

Well-Known Member
Joined
Aug 15, 2016
Messages
129
Reaction score
125
Location
Indiana
So here is what I have. HEI Ready to Run Distributor from TSP which I purchased from PACE Performance. I have power to it(Red wire) when key is in ON and START positions. I have power to the Tach wire(Yellow) when key is in Start position. I have checked engine
ground. I have ran a jumper to ground from the actual ground wire at the coil, which is inside the top of the distributor housing. I have cleaned(again) the distributor hold down, the bolt, and the block around the base of the distributor. I have checked for spark at the plug and on the top of the distributor. They sent me a new one because I figured it was a bad unit, but still no change. The strange thing is that it ran great when i did the initial break in on the new build, which was just a few weeks ago, and I haven't touched anything to do with the distributor since. What else can I try?
 
or-wiring-diagram-msd-ready-to-run-distributor-within-mallory-unilite-distributor-wiring-diagram.jpg

dist neg does not go to ground
 
What is this yellow tach wire? Do you have the destructions? LINK?? to the destructions. ^^Above post is right you do NOT ground the coil NEG
 
Actually, it’s the model with the integral coil.There are only 2 wires to hook up, power and tach.
 
Last edited:
UNHOOK THE TACH and try it. Unhook the power wire and jumper straight to battery. N yeh^^ is the rotor turning?
 
it is a very simple system from the diagram. Is it possible that it was damaged by running it with any combination of wires other than the way the diagram showed. IE if the first one worked then you hooked up the tach and now it is dead. and the second one is dead ( presumably with the tach wire still hooked up) maybe the tach wire is killing the unit? (pure speculation)

In your first post you said you had power at the yellow wire when in start, the diagram does not show the need for that.
 
You Sir, are the MAN! Unhooked tach wire and it fires. So now, explain to me why that’s the case? Also, how do I hook up the electronic tach now?
 
I would guess the tach has a problem, or the wire is shorted, like were it goes through the firewall, etc.
 
Contact the tach manufacturer and the dist manufacturer and see what they recommend.

waaaaaayyyyyy back in the day there was an adaptor that hooked up to the coil / dist wiring and it pulled a tach signal without being electronically connected to the dist wires. (like a clamp on amp meter)
 
These should not need that. Tach adapters are for stuff like CD/ MSD ignition boxes. These are a 'switched' ignition, just like GM HEI, Mopar ECU, or breaker points

"Back in the day" I ran Tiger/ Delta/ SST CD ignition and had one HECK of a time getting a tach to work. Interestingly, the Heatkit tach in the day had an magnetic pickup which would deal with it. "Sun" had come out with a brand new version "one piece" "all electronic" tach about 1971?? ish. I waited fore one........and......it didn't work......

Ended up putting a cable drive Jones/ Motrola in the car A guy had a Prestolite dual point hemi tach drive distro for TWENTY FIVE BUCKS!!!
 
I spoke to Auto Meter, they couldn't come up with a reason it wouldn't work. Their suggestion was to tie the tach and coil grounds together.
 
MD68 said:
I spoke to Auto Meter, they couldn't come up with a reason it wouldn't work. Their suggestion was to tie the tach and coil grounds together.
Click to expand...

There IS NO coil "ground." (Unless you are running MSD CD/)
 
Yeah, I told Auto Meter how everything was grounded and that's all they could come up with. I will try to run a ground wire from the tach ground to the 'ground' wire that runs between the coil and the module inside the distributor. It can't hurt to try it I suppose.
 
Lets see isn't the issue that the tach killed ignition spark? I doubt grounding the tach will fix that, but you never know.
 
Dont know for sure but if you ground the negative side of the coil I suspect that you will not produce a spark. On a standard point ignition the negative side of the coil goes through the points to make and break the ground thus producing a spark. if you grounded the negative side there would not be an opening of the ground to the coil to allow the coil to spark. My guess is that the HEI type of coil works the same way and the pickup in the dist simply makes or brakes the negative side of the coil.
 
Dana67Dart said:
Dont know for sure but if you ground the negative side of the coil I suspect that you will not produce a spark. On a standard point ignition the negative side of the coil goes through the points to make and break the ground thus producing a spark. if you grounded the negative side there would not be an opening of the ground to the coil to allow the coil to spark. My guess is that the HEI type of coil works the same way and the pickup in the dist simply makes or brakes the negative side of the coil.
Click to expand...


Which is exactly what I was attempting to convey LOL
 
You must log in or register to reply here.
-

Back
Top