ignition resistor

[kodiak2]

I recently transferred a engine from a PW to a M37 which already was converted to 12volt. I was given a coil and told I would not need a ignition resister with it. The problem I have is a very weak spark and it will not fire on gas, but will hit on starting fluid (even a short squirt) Anyone have any ideas? Was I given bum information?

[Matthew Ziegler]

ignition

If you have a 12 volt truck and a 12 volt coil, I see no need for a resistor. what kind of shape is your distributor in, points? how old is the coil etc.

[DrPepper]

The resistor is for running only....

If there is no resistor and the coil is 12V, test to make sure you have 12 V at the coil and a perfect ground for the distributor points to ground thru. This should give you a good spark, otherwise the coil may be bad.

The typical resistor wiring to the coil should be in the "run" circuit. The resistor (as I remember it) was intendid to reduce the point arc (increase lifespan) when the engine was running. When you start the engine the "start" circuit bypassed the resistor for full voltage to the points.

DrPepper

[kodiak2]

resistor

Thanks guys. I had to give up on the M37 and pull it out of the garage and put my wife's car in due to it being around -20F in the mornings here. Will try your suggestions when I start working on it again. With a block heater,oil pan heating pad,tranny pad and a battery heating pad, it gets expensive plugging the vehicles in here.

[Charles Talbert]

I'm suspicious; I'd suggest you do a compression test on the engine. That will tell you quickly whether you need to continue to troubleshoot a distributor problem or whether the real issue is with engine internals.

[kodiak2]

Work on hold (-40F)

Sorry in taking so long in replying. When I start working on the M37 again, I will check the things you guys suggested. Right now, it sits outside as I have to use my garage for other things due to the outside temperture which has reached -40F at night. My daughter lives in a aptly named town of North Pole, Alaska, only about 30 miles away and her lowest reading so far has been -56F.

[pwrwagonfire]

I am very interested to see what suggestions you get here...because I am having the EXACT same problem. To a tee.

I checked and made sure the distributor rotor turns, put on a new cap, new rotor, new coil, new spark plugs. I rewired a bunch of stuff in the ignition system due to old corroded and disintegrating wires. Still nothing.
I also just had my engine completely gutted and re-built last summer.

I have new points and a new condenser ready to go in, but haven't had a clear day for it yet.

Have you made any progress?

[kodiak2]

wont start

I'm sorry to see someone else having the same problems. I'll be starting work on my truck soon as it's warming up here. (+20F) during the day. Planning on doing a rewire job and installing more grounds plus working on the suggestions from the forums.

[pwrwagonfire]

I'm sorry to see someone else having the same problems. I'll be starting work on my truck soon as it's warming up here. (+20F) during the day. Planning on doing a rewire job and installing more grounds plus working on the suggestions from the forums.

If I get to my truck first and fix the issue, I will be sure to post about it here for you!

[kodiak2]

Cold weather.

I'm finally getting to work on my truck. Just ordered a exhaust pipe from VPW. Was under my parts truck today which has a coolant heater plumbed into it. Noticed today it is plmbed through the oil pan which has me intrigued. Now, I'll have to add that to my list of things to look at.This truck also has NDD tires with studs placed in them. They look just like regular studs one would have installed at a tire shop.