Ignition Control Module, Mode of failure?

This is the place to get help with technical matters concerning your M151 jeep

Moderators: rickf, raymond, Mr. Recovery

Post Reply
rstel01
Private First Class
Private First Class
Posts: 22
Joined: May 11th, 2018, 10:00 am

Ignition Control Module, Mode of failure?

Unread post by rstel01 » September 2nd, 2018, 10:45 am

Hi all,

Does the Swiss Controls Ignition Module usually follow a mode of failure when it starts going?

This morning after about a month of very successful drives/shakedowns, had a partial breakdown of a lack/loss of power after sustained speeds above 45 mph.

Taking wife out for breakfast and a run at sustained speeds above 50mph higher rpms, suddenly lost power/throttle response (no stall). Pulled over, idling fine did not seem to be fuel related (sight glass of line showed full)

In 3rd above 30 or so, power started falling off, not really bucking just losing power. Got off main road, lower speeds/lower rpms OK until having to start to pull a hill and then it would just fall off again. Just let it stay in 1st/2nd for some time on a single lane just off idle and idled (neutral) down hills. Got it back home and after cool down, runs great again.

Coil was replaced a few months ago with a brand new USGI NOS (not chi-com copy) that I spent a fortune for after reading everyone's horror stories about coils. Carb is new, all filters replaced.. I went through a month of issues with carb and vac problems and it has been just running stellar since working through all that. Also as a sanity check, I open the gas cap just in case (I have a new vented but, always confused on if it should say "open" or "closed" when looking at for normal operation). Cap is also new, as are the other parts of the secondary ignition.

It is almost acting like an older Ford TFI (thick film ignition) module on a distributor, when they would start to fail at higher rpms/higher loads.

In everyone's experience, when the ignition module starts to fail does it do it in this fashion or just stop working?

User avatar
m3a1
Lt. General
Lt. General
Posts: 4030
Joined: August 7th, 2014, 6:36 pm

Re: Ignition Control Module, Mode of failure?

Unread post by m3a1 » September 2nd, 2018, 3:27 pm

Disclaimer - my experience was with a Prestolite module.

YES, failure can be experienced in a number of ways, including weakened spark (and from that we can conclude loss of power at higher RPMs as well)

Fail to restart after getting hot...

Failure goes from weakened spark, all the way to abrupt and total failure.

Check the bottom of your rotor and edges of the chopper on the rotor. Is is brushing against anything? Is the gate (through which the chopper passes) clean and free of dust and debris?

Look beneath the module. Everything intact and moving freely on the advance mechanism?

User avatar
rickf
General
General
Posts: 19741
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Ignition Control Module, Mode of failure?

Unread post by rickf » September 3rd, 2018, 6:45 pm

What you are describing sounds like a fuel delivery issue. Filter may not be clogged but what about the in tank filter or the fuel pump? Is this an A1 or A2? Electric fuel pump or mechanical? I would do a fuel flow test and see if the flow and volume are there.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

rstel01
Private First Class
Private First Class
Posts: 22
Joined: May 11th, 2018, 10:00 am

Re: Ignition Control Module, Mode of failure?

Unread post by rstel01 » September 15th, 2018, 2:47 pm

rickf wrote:What you are describing sounds like a fuel delivery issue. Filter may not be clogged but what about the in tank filter or the fuel pump? Is this an A1 or A2? Electric fuel pump or mechanical? I would do a fuel flow test and see if the flow and volume are there.
yup.. ironic filter on Carb and less than 2 months old. Must have been a import copy.

I just went with a straight pipe fitting to the carb now and use the larger clear inline I had put previously.

Oh well needed excuse to replace Fuel Pump, Ignition controls and Capacitor, they were the last sub-systems on the powerpack not replaced or rebuilt.

Dang thing is downright "sportscarish" now :)

User avatar
rickf
General
General
Posts: 19741
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Ignition Control Module, Mode of failure?

Unread post by rickf » September 15th, 2018, 6:17 pm

The threads in the carb are NOT pipe thread! Well, They are now, be very careful because you can break the inlet area of the carb.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Post Reply