Cranks and wont start ongoing issue

-
Cravin'sCuda

Cravin'sCuda

Well-Known Member
Joined
May 9, 2007
Messages
101
Reaction score
7
Location
Novato
Looking for a little insight on a ignition issue that has me stumped. About a year plus ago I removed my Fast EFI and Mallory Hyfire 6 and went back to carb and to the regular hook up of the distributor (Mallory Unilite) through the ballast. When I hooked it up it almost started then would only crank (no spark). I re-hooked the Hyfire still no start and went through the troubleshooting for it and I have spark but no start (Unilite module bad). I replaced the module,(removed the Hyfire) reconnected back to ballast tried to start, it gave a almost start then just cranked, fried another module. "Definition of insanity". Installed another module, hooked it up to the Hyfire and life is good car runs. I do know that when then the unit is hooked up without the Hyfire and I put 12 volts to the positive side the voltage on the negative side is almost half or more and when I disconnect the wiring harness to the distributor all the voltage comes back (shorted module).:banghead::banghead:
Fast forward to today, I have had the engine completely rebuilt, installed a new trans and converter, got it all hooked up, got my new MSD RTR 8388 dist, didn't use the Hyfire CDI box, crank, crank, crank, "woof" took out the module.:banghead::banghead: When I check voltage at the coil (ballast bypassed) full 12 volts to positive side per MSD instructions, I have about 10 volts positive and on the negative side its about 4.5 volts and once I disconnect the 3 pin and all the voltage comes back (shorted module). I hooked up the Hyfire that I had and can get spark out of the coil but no start. This module wont be cheap to change, but I cant seem to figure whats wrong. Sorry for the long wind but its been very frustrating.
 
Geez that is impossible for me to follow. Let's start and end simply. "What is on there" now, EXACTLY?

Is this an MSD stand alone distributor? That is, it's not CD? Post a part no. and link to the destructions. They are at the MSD website

I SERIOUSLY DOUBT that you have "taken out" all those modules, unless you have somehow seriously wired it wrongly. So we need to CAREFULLY go through just exactly and I mean EXACTLY how you wired it.
 
Right now is the stand alone dist. MSD 8388 Ready to run. The ballast is bypassed using a 10 gauge jumper wire connecting the run and crank wires like the one for a FABO ignition. 12 volts supplied by these wires to the positive side of coil, red MSD to the positive side, orange to the negative side and black to ground (valve cover bolt). The Mallory's were stand alone also.

http://www.msdperformance.com/Products/Distributors/Chrysler/Ready-to-Run/E-Curve/8388_-_Chrysler_318-360,_Ready_to_Run_Distributor.aspx
 
Know what? You might have a SHORTED ignition coil.

Pull all wires off the coil. Measure resistance across the two terminals, and check for resistance to ground (coil case) which should be infinite. Post results back

What coil are you using?

Also is there ANYTHING else hooked to the coil? If you have a radio supression cap, and or a tach wire, I would disconnect both until you get this sorted.
 
I'm using the MSD Blaster 2 coil, I bought it last year when dealing with the same issue with the Mallory.
Across the two terminals-(primary) .6 ohms- spec per MSD-.7 ohms
Across the terminal to secondary- 5.09k ohms-spec per MSD-4.5k ohms
Primary to case-O.L
Secondary to case-O.L
Nothing else to the coil.
 
Fresh rebuild, if the timing is Close and your getting spark and have fuel it will will start, I just had this problem over the weekend, my car would crank and crank and crank but wouldn't turn over, so I got mad at it and hit the gas to the floor about 5 times while cranking on it and it fired right up
 
You keep talking about spark and such. But I see no mention of fuel. Does the carb work? Are you getting fuel? Have you made sure the fuel you are getting is good? Have you tried starting fluid?

Fuel. Air. Spark. That's it. Don't over-complicate it.
 
It is a fresh rebuild, it came straight from the dyno and planted into the engine bay. I never removed or touched the dist except for removing the cap when dropping it in. It was getting plenty of fuel and maybe a little to much by the back fire. On the next crank cycle it was like it almost started and then nothing. I checked for spark and nothing. I had to walk away with my head hung low, Getting dark, pissed off and ready to put it on Craigslist and say LATER. Went back the next day, reconfirmed what I did the night before and back to no spark.
I need to call MSD and see if there are any checks I can do the Dist, there web site only shows for the two wire and not the three.:banghead:
 
Kit, I agree that it might be, its the one thing that is constant. When I check it to the battery it has 0 ohms, but cranking that can change. I have a ground strap at the back of the block to chassis and the battery to the front of the block. I need to talk with MSD, when I check the 3 wires to ground coming out of the dist the "orange" wire which does go to the (-) side of the coil, has 1.5 ohms to ground, the red wire is O.L and the black ground wire is O.L. Which tells me I shorted it out. With the 3 pin connector hooked to the coil and key on and the way it should be.

Battery voltage-(11.7 volts)
key on at coil (+)-(10.7 volts)
key on at coil (-)-(6.5 volts)
cranking at coil (+)-(9.0 volts)
cranking at coil (-)-(5.5 volts)

3 pin at dist disconnected everything else still hooked up

Battery voltage-(11.7 volts)
key on at coil (+)-(11.5 volts)
key on at coil (-)-(11.5 volts)
cranking at coil (+)-(9.5 volts)
cranking at coil (-)-(9.5 volts)
 
The thing is simple. You can hook it up on the bench. Hook up the two coil wires, hook up the ground and hot lead to a battery, and put a spark tester (gap) in the coil. Bind the coil can (if metallic) to the battery ground, and your spark gap of course goes to ground. Spin the dist, it should make sparks.
 
From your voltage readings your battery is discharged, or has a bad cell.

Pulling the 3 pin connector with power on, may blow a module. The resulting coil discharge, has no good place to go. The voltage readings suggest 7.4A flowing in coil primary with key on. That mean driver circuit is in current limit mode, ready to spark. Pulling connector makes spark... the path it takes on the pull, is likely bad.

The instructions show a variable reluctance pickup, have you checked the gap with non ferrous feeler gauge?
 
You must log in or register to reply here.
-

Back
Top