2.25 not firing 3&4 ?

[Lance]

Don't know if anyone is still out there but I think I'm on to something.
Yesterday I was working on the Rover again & found that if I unplug spark plug wires 1&2 then 3&4 will fire BUT when I do this I get a spark that is jumping from the valve cover to anything grounded! If I plug 1&2 back on then 3&4 stop firing the spark goes away & 1&2 start firing. Something shorted??? where to look??? I have swapped dissy with spare but that doesn't change anything.

[SafeAirOne]

I'd change the plugs and wires and probably the rotor and cap too. Then you've eliminated any leakage anywhere in the secondary circuit.

[albersj51]

I agree with Mark. It sounds like really bad plug wires.

[Nium]

Is the ground strap from engine to chassis sound?

[Lance]

I will check the ground strap.

[Apis Mellifera]

I suggested cap, wires and rotor in post 6. In post 7 he said he's already replaced them.

I've heard that if the coil is wired backward it will do strange things spark-wise. Also, there is an arch from the valve cover to ground? Isn't the valve cover either grounded already or if the gaskets are in good condition, isolated completely?

[Lance]

I'll try reversing the wires on the coil. Almost seems like something is drawing the coil down. Has enough spark for two plugs, Pull wires off 1&2 then 3&4 work.
From earth to negative side of coil has steady 10 volts. Positive side of coil has 13 volts. Across coil (neg. to pos.) I have 4.5 volts. Does that sound normal?

[Apis Mellifera]

Assuming the truck is negative ground, you should have battery voltage on the + side of the coil and the - side should go to the points. I'm not sure what to make of the voltages you've provided, but it doesn't sound right.

I think I would completely bypass the wiring harness. Disconnect the low tension coil wires. Jumper from battery + to coil +. Jumper from coil - to points. Start truck then turn off key. The truck should still run, but you will have (hopefully/in a normal truck) disabled all switched 12V. This will isolate it as either a wiring problem or a distributor problem.

At this point, I'm leaning toward an improperly isolated points set, which is easy to do, or some other fault inside the distributor.

You say that it will run either on 1 and 2 or 3 and 4. Will it run or 1 and 3 or 4 or 2 and 3 or 4?

[Lance]

Just tried both of your suggestions. It will run on different combos of wire configurations even on one cylinder. Connected coil so it was off the harness straight to the battery, switch off. No change???
Seems to run on any two cylinders, doesn't matter which two but only two??

[SafeAirOne]

Hmm...How'd that engine-to-chassis ground strap check out? Did you clean off the contact surfaces so you're sure you have a good, conductive path?