Electronic Ignition: Pertronix 141a 24v Add'l Ground Wire

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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DieFledermaus
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Location: Lewes, DE 19958

Electronic Ignition: Pertronix 141a 24v Add'l Ground Wire

Post by DieFledermaus » Tue Dec 07, 2021 6:06 pm

Hi Gee,.
I run Pertronix kits in my jeeps. Have any of you added an extra ground wire to the base plate and then out of the 24v distributor housing to a ground on the block? To the starter foot or something tidy? I ran an extra ground wire in my 6v '44 MB and have had no issues in 11 years. My latest M38 runs erratically. Smooth as silk for 20 miles and then runs rough and then runs smoothly again. The M38s are both 24v. I read the Pertronix kits are sensitive to grounds. Everything is new, and I mean everything. Jeep purrs along at 40mph for 20 miles and then runs rough and then purrs again. Carb and fuel pump are NOS and rebuilt and tested. Carb is clean and has the correct spacer for fuel pump pressure. Solid state voltage reg. NOS spark plug wires, cap, rotor, plugs etc. Gapped correctly. Air flow is not redtricted. Engine has 250 miles on her; ran perfectly on test stand for 30 hours. Valves adjusted. Exhaust manifold flapper works correctly. I can go on and on...it's essentially a new jeep.
Just wondering. I've been going through the TM checklist.
Mike
AUG 1944 MB, US NAVY
MAR 1952 M38
APR 1952 M38
1957 F2A AERODROME TRAILER
1993 M101
A & P mechanic
Delaware 19958


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DieFledermaus
G-Second Lieutenant
G-Second Lieutenant
Posts: 515
Joined: Tue Oct 14, 2003 6:37 pm
Location: Lewes, DE 19958

Re: Electronic Ignition: Pertronix 141a 24v Add'l Ground Wire

Post by DieFledermaus » Sat Dec 11, 2021 3:14 pm

Problem solved! It was the Pertronix electric ignition grounding issue. I read these Pertronix kits are sensitive to grounds and indeed they are! Now the Jeep cold starts in 2 seconds and runs smoothly. Yay!
-Best,
Mike
AUG 1944 MB, US NAVY
MAR 1952 M38
APR 1952 M38
1957 F2A AERODROME TRAILER
1993 M101
A & P mechanic
Delaware 19958

User avatar
DieFledermaus
G-Second Lieutenant
G-Second Lieutenant
Posts: 515
Joined: Tue Oct 14, 2003 6:37 pm
Location: Lewes, DE 19958

Re: Electronic Ignition: Pertronix 141a 24v Add'l Ground Wire

Post by DieFledermaus » Fri Jan 07, 2022 1:22 pm

Hi Gee,

Just a follow-up...perhaps this should be in the M38 Modifications forum but too late now. I spoke with the Pertonix tech. He said that 99% of the problems with Pertronix kits are ground related. Test: With a multi-meter set on resistance, attach one end to the points/module plate and the other to the neg terminal of the battery. The reading must read ZERO Ohms. Even the slightest resistance will interfere with how the module works. A reading of 0.2 Ohms is a no-go. Make sure the block is well grounded to the frame. All for now,
Mike
AUG 1944 MB, US NAVY
MAR 1952 M38
APR 1952 M38
1957 F2A AERODROME TRAILER
1993 M101
A & P mechanic
Delaware 19958


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