79 Power Wagon 360 no start progress.

fixerupper · Jun 12, 2018

I posted a few days ago about my 79 power Wagon not having spark. It sparked out of the secondary wire (big wire) once when the starter was hit, then no more spark. The battery was getting tired from extended cranking but was still turning it over, now grunting yet. I checked the resistor and it had power at all four terminals using a test light but I still replaced it. I cleaned up the grounds for the ignition module on the firewall slick and clean. Still no start. Replaced the module, no start. It was still cranking but acting tired. I threw the charger on it and walked away for the rest of the day. This evening with a good charge on the battery it popped right off. In the past it has always started if the battery was low and barely able to crank it over. Now it needs a good charge in the battery to get spark. Any ideas? The battery had been doing a lot of cranking off and on before I charged it so the battery held up well enough to be called a good battery. Connections are clean and tight.

Steve@Advance · Jun 12, 2018

If you have a good analog volt meter, check the battery voltage while cranking. It should be around 9-10v minimum. If low, have the battery load tested.

Also check between the + terminal of the coil and ground while cranking. It should be close to the battery voltage. Not sure how it does it, but something switches the power from one side of the resistor to the other, or bypasses it all together, been a few years...

Those also had a reputation for ignition switch failures, overheating internally and melting the harness plug. Be sure it always gets good coil voltage when it is in the crank position.

Another problem, if it has an amp meter on the dash, check the terminals. They would get loose, burn, loose good connection. Cause charging problems, low voltage, flickering lights...

How's the starter sounding? Possibly it has some bushing wear, drawing too much amperage, not enough left for the spark.

fixerupper · Jun 12, 2018

(quoted from post at 18:31:40 06/12/18)
If you have a good analog volt meter, check the battery voltage while cranking. It should be around 9-10v minimum. If low, have the battery load tested.

Also check between the + terminal of the coil and ground while cranking. It should be close to the battery voltage. Not sure how it does it, but something switches the power from one side of the resistor to the other, or bypasses it all together, been a few years...

Those also had a reputation for ignition switch failures, overheating internally and melting the harness plug. Be sure it always gets good coil voltage when it is in the crank position.

Another problem, if it has an amp meter on the dash, check the terminals. They would get loose, burn, loose good connection. Cause charging problems, low voltage, flickering lights...

How's the starter sounding? Possibly it has some bushing wear, drawing too much amperage, not enough left for the spark.

The ammeter is long gone. After the second one burned up I bolted the wires together and that ended that problem. The starter hasn’t been on it all that long, maybe 5000 miles but it’s a rebuilt and you know how well rebuilt starters last. I have not checked the voltage at the coil. If I can corral my son some day I will have him crank it while I watch the volts. The ignition switch was replaced many years ago so it is subject also.

Bob · Jun 12, 2018

Those wonderful FLAKY Mopar EI's!

One thing comes to mind... that 4 terminal ceramic resistor has two wire-wound resistors in it, with different Ohm ratings.

Originally, it likely had two plastic connectors that could only be plugged in one way.

If those connectors have been replaced with plain ones, or the plastic bits that determine how they are plugged in have crumbled away you may have it connected up with the two resistors mixed up.

You can probably find some diagrams on the 'net showing how to properly connect it, ot I have some printed info at the shop I could post later.

Tx Jim · Jun 13, 2018

Did you check to be sure engine is turning over?

Back in the mid 80's I purchased a '77 Power Wagon for $300 that was advertised with having no compression on engine because starter spun over very easily. After some diagnostics I discovered the flex plate on torque converter was broken& engine wasn't spinning when starter was engaged. Slid trans back R&R flex plate,slide trans forward then started engine & drove it out of the shop.

fixerupper · Jun 13, 2018

Bob I didn’t realize the resistor has two different windings till I looked at wiring diagrams last night. The original resistor was there from the factory, I bought this pickup new and to my knowledge it has never been unplugged till yesterday. I don’t put more than 500 miles a year on this thing a year but I do want it to start up and run when needed. 7.5 mph is quite a deterrent to frequent usage. LOL

ss55 · Jun 13, 2018

That sounds normal. Chrysler products of that era won't produce a spark if the voltage drops below about 11 volts while cranking the starter. The problem usually shows up when morning temperatures drop to freezing in Fall. If charging the battery or jump starting it with a a good battery works, then it is time for a new battery. In a non-Chrysler product, your old battery might still last the summer or maybe give another year of service.

fixerupper · Jun 13, 2018

This morning when I started it, it cranked nice and fast but no fire until I let off on the starter, then it started. This tells me low or no voltage to the ignition while starting. (Duh!) back when this pickup was darned near new I had this exact problem and it ended up being a wire backed out in a plug in the firewall. The backed out wire was the resistor bypass wire for starting. Not saying that’s the problem this time though. Soon as I get some time and help cooridinated I’ll do some voltage checking. I do have a wiring diagram.

Eagle Doc · Jun 13, 2018

I had an 86 Dodge with 318 that got to a point it sometimes would not start. Like yours sometimes it would hit and start after I let off the starter. It was a four speed stick and after a while I found I could put the truck in neutral, give it a push and jump in and put it in third gear, pop the clutch and it would start. The problem turned out to be the gap at the pick-up in the distributor was a little too wide.

fixerupper · Jun 13, 2018

I’ll check that gap out. Now if I only knew what it should be set at.

Eagle Doc · Jun 13, 2018

Sorry, that's been a long time ago and I don't remember the specs. I do remember I had to use a brass feeler gauge.

fixerupper · Jun 13, 2018

Some feeler gauge sets have that one brass feeler in the set. Maybe that’s the one or is it for a Chevy.

79 Power Wagon 360 no start progress.

fixerupper

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Steve@Advance

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Bob

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Tx Jim

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ss55

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