Dodge truck electrical problem.

I have a 70, or early 80's dodge pickup. It's another present my brother left me. It's a slant 6. I have no spark. Under the distributor cap I was expecting to see a set of points. It has a rotor, and a pickup coil of some kind, the distributor haft has raise bumps. In all my time working on engines, I have never come across this set up. I put a hot wire to the coil, just like you would do for a point distributor. No fire. Where do I start trouble shooting? Stan

Dodge start with electronic ignition in the early 70s and good chance the module in he distributor is bad

You have a first generation Mopar electronic ignition. It has 4 main components: the reluctor inside the distributor, an electronic module mounted on the firewall, a ballast resistor (also on the firewall), and the coil.

Failure of any of the above results in a no spark situation.

My experience is failure the ballast resistor or the electronic module are the most common cause of ignition problems.

I am a big fan of dodge trucks and of slant sixes.
Like others say, early electronic ignition.
Here is a system diagram if it helps to have the whole picture

Putting power to coil and no spark. I would first replace control unit. The control unit replaced the points.
Did you measure the current when you powered coil?

Very common for the ballast resistor to fail. See if there is a spare in the truck, Dodge owners knew to always carry a spare!

Should have voltage at the + coil terminal, key on AND while cranking. Probably not full voltage, but enough to burn a test light. The - terminal should flash a test light, like points would. If you get the flash and no spark, suspect a bad coil.

Also be sure the distributor is turning. Some had a plastic drive gear.

The pick up coil in the distributor should show some continuity with the ohm meter.

If everything checks out replace the module.

Chrysler started using electronic ignitions in 1972. Those early electronic ignitions need a strong battery to get a spark. If the voltage drops too much during cranking the engine will spin just fine, but you won't get a spark. Try a different battery, or connect a jumper battery for extra power.

Beyond that, I would check if the ground side of the coil is intact and work up hill from there. The factory service manual is very helpful when trouble shooting, BTDT.

x4 Ballast Resistor.

Way back in the early '80s, I worked at a independent shop. One evening, close to quitting time, a guy had parked his big ol' boat of a Chrysler across the street in the grocery store parking lot and after he came out of the store, his car decided it wouldn't start. The guy had walked over to our shop and was wondering if we could tow his car over and troubleshoot it. I looked out the window to verify what I needed, grabbed the dual resister that we had in stock, along with a ratchet and a socket to fit the screw that held it to the firewall. I walked over to the car and replaced the dual resister without putting an ohm meter across the leads. Two minutes later I had the guy try to start it and it took right off. I realize I got lucky on thinking it was the resister pack and I guess I would have looked bad if the car didn't start, but it was just a lucky guess that worked. The car owner stood there stunned that I fixed it so quick and I think the boss only charged him a couple of bucks as that was the priced marked on the box with no service call. (You gotta remember this was decades ago when things were cheaper)
At that time, I recommended that every Chrysler owner carry a spare resister, the GM owners have a four-pin HEI module and the Ford owners carry the spare aluminum module in their glove box.

Note the control module is ground at the base and Chrysler is know to have poor grounds. It took me a bit to figure out repeated module failures were because of a poor ground at the module base.
I got to the point I always ran a dedicated ground from the engine to a module mounting screw and like magic no more module failures.

I still have a Mopar ballast in the glove box of my tow truck... I also kept GM HEI distributor rotors in it... When in a jam I strip a length of wire to get a strand and wrap all four ballast terminals. I have patched the hole burnt in GM rotors with bubble gum.

I made made good money on those break downs. Folks were happy to get it going on the side of the road those days are gone...

If it where to start by die when you let off of the start position of the key it is the ballast resister. I've had it happen to me and I by passed it to get to a part store. So not likely to be your problem

In recent years somebody wised up and started making a single wire HEI distributor for these as they always were maintenance happy. For about $110 you can drop in a GM style distributor and toss the fine system that the dodge bros came up with. got 2 and like them a lot. Fred

Do you have a distributor an old slant 6 with points?

I used to pull my distributor to replace points.

I'm guessing they used the same distributor, modified it and added the electronic points and pick up.

All else fails, cheif could go back to points and condenser.

Bubble gum? Who would have thunk that gum is an insulator?
I used to carry a spare ballast and VR in my 67 cuda.

Also spare brushes for alternator..

(quoted from post at 19:18:03 11/04/21) I have a 70, or early 80's dodge pickup. It's another present my brother left me. It's a slant 6. I have no spark. Under the distributor cap I was expecting to see a set of points. It has a rotor, and a pickup coil of some kind, the distributor haft has raise bumps. In all my time working on engines, I have never come across this set up. I put a hot wire to the coil, just like you would do for a point distributor. No fire. Where do I start trouble shooting? Stan

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Specific year and system would be quite helpful.

All replies so far have been concerning the very good, IMO, original Mopar electronic ignition. Nothing wrong with it at all if you have an understanding of it.

However, late '70's through '80's many Mopars had the terrible "Lean Burn" system, whole 'nother ball game there. Most of those got converted back to the original type electronic ignition.

Not knowing what you have makes it impossible to help you.

Yes they had a distributor but the electronic part bolted on different then points if I remember right. Yes I 2 hated to put new point in due to where the distributor sat

(quoted from post at 17:18:03 11/04/21) I have a 70, or early 80's dodge pickup. It's another present my brother left me. It's a slant 6. I have no spark. Under the distributor cap I was expecting to see a set of points. It has a rotor, and a pickup coil of some kind, the distributor haft has raise bumps. In all my time working on engines, I have never come across this set up. I put a hot wire to the coil, just like you would do for a point distributor. No fire. Where do I start trouble shooting? Stan

Click to expand...

ake sure you have voltage at ballast resistor....should be battery voltage on both terminals that are wired together, key on.
you can disconnect wires and measure Ohms of ballast resistor. Connect meter to two spades along the long side of unit and one side will be 5.0 Ohms and the other 0.5 Ohms +/_ a bit. Unplug sensor connector near distributor and connect Ohmmeter and measure ~ 300 t0 600 Ohms.