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glennsea 04-13-2010 07:18 PM

Engine shutoff while driving
The other day I was out running some errands and stopped at a gas station. I came back out, started the Jeep and drove through the parking lot and out into a side road when my Jeep just shut off. Nothing like gas, bogging, etc. it just died. I tried to start it to no avail. The engine is an AMC 360. Coil is currently Blaster 2.

I had it towed home and started looking to it. The only thing I could see obvious was that the ballast resister was low on the out terminal, around 2 volts. I got a new one at the correct ohm setting and it look fine now but it still wonít start.

It has a typical wiring of battery to ignition to ballast resister to pos term on coil. Neg on coil goes to tach and dist. There is also a wire from the starter sol to the ballast resister, same term as the ignition wire.

With ignition on I am getting 12 volts from the ignition. I am getting around 6.X volts out of the ballast resister and same on coil from there. I have bypassed the ballast resister with ignition wire to pos coil term and get around 11.6 there.

I had my wife start the Jeep with me holding the coil HV wire, dist end about ľ inch from the block and see no spark. I changed to another coil I had and a new HV wire and saw no spark there as well. I have made a new wire that reads good, I have tested resitance of the coil and it is right on. I removed the neg bat wire from the block, cleaned and reinstalled. I cleaned all of the connectors for the various components, etc.

I am lost at this point and donít know where to look. Could it be the dist itself? The condenser? The points were recently changed and look ok from what I can see but I have not done this before. The dist is a Mallory Series 25 Dual Point.

Bill Adkins 04-14-2010 09:22 AM

What type of ignition system is it. Is an old standard type using ign points and coil or does it have an electronic control module. In any case the points are an intermittent ground allowing current to flow through the coils primary winding and then stopping it so as to collapse a magnetic field in the coil. If the points are dirty of the wire interrupted or if it has a condenser / small metal can hooked to the points the circuit wont work. If it's not electronic it will be easy to test. Using a test light attach the clip to the engine in a non painted surface and turn the ignition on. You will have removed the distributor cap prior to this point. Points closed the light should not light up as the voltage is going to ground through the points. Points open the light will light up. If this doesn't happen you need to discover why and resolve it. If the car has an electronic ignition system do not use a test lamp as some systems don't respond well to a low impedance lamp being used..... that means a standard test light.

cobalt327 04-14-2010 09:38 AM


Originally Posted by glennsea
I had my wife start the Jeep with me holding the coil HV wire, dist end about ľ inch from the block and see no spark.

Have you also checked the coil secondary wire ("HV" wire) to see if it's still OK? The other thing that comes to mind is a bad condenser.

jon72vega 04-14-2010 10:15 AM

Unhook the tach signal wire & try it.
I had a bad tach cause a similar problem.


PatM 04-14-2010 03:48 PM

Jon -- That was gona be my suggestion. Ya beat me to it. A bad (or grounded) tach will do it.


glennsea 04-14-2010 04:02 PM

No luck. I have bypassed the wire from coil neg to dist as well as wired straight from bat pos to coil pos and removed the tac. Still won't start.

T-bucket23 04-14-2010 04:07 PM

Is it points or electronic

eloc431962 04-14-2010 04:11 PM


Originally Posted by T-bucket23
Is it points or electronic

It's a points set-up Mallory Series 25 Dual Point. Chet


glennsea 04-14-2010 04:27 PM

I bypassed the wire from the coil neg to dist as well as wired directly from bat pos to coil pos just to test with no change.

I guess I need to start looking at the dist at this point.

Bill Adkins 04-14-2010 04:34 PM

If you re-read my earlier post it will shed some light on the diagnostic procedure for a standard ignition

glennsea 04-14-2010 04:56 PM

Thanks Bill. I don't happen to have a test light at this point nor a working car to go get one. Catch 22 or chicken before the egg?

glennsea 04-14-2010 05:46 PM

OK, I disconnected one set of points and get a spark. I disconnected the working one and connected the one that was disconnected and get a spark. I connect them both back up and no spark.
Can I remove one set completly and run single until I can get another set?

Bill Adkins 04-14-2010 06:11 PM

nope, they work as a set but something isn't set up correctly. Replacement of the dual point dist is something to consider as they require a distributor machine to get set up really right. A single point set up or even a later electronic hall effect system would be an improvement including dependability.

Bill Adkins 04-14-2010 06:44 PM

A thought, for the test to work the circuit for the points has to open or closed meaning both sets of points need to be open to collapse the field in the coil so if one isn't working correctly it wont work. A search for dual point ignition is needed for a better circuit explanation. I did look at Summit hot rod parts as I have a catalogue and a complete HEI distributor is like 170.00 and a Pertronix point replacement set is 70.00 so it's not all that expensive to resolve. I would probably go for the HEI as it has a coil and the whole system built into it. Summit, Jegs, Speedway are all good sources for parts.

glennsea 04-14-2010 07:46 PM

I removed one and it fired right up. It started to bog after a while and shut off. I installed the other one and removed the one I left and it fired up and never stopped.

Turns out the first one was rubbing the mount screw for the point so in my testing I must have moved the wire correct.

I am looking into a replacement as the one I have now I can't get parts for locally. I can order some replacement parts for around 70.00 that will turn it into an electric one and I won't have to worry about this anymore.

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