93' W2250 5.9L Magnum

Getting my plow truck ready for winter, been parked since April.
Turned key, nothing, left key on crossed starter terminals
and fired up, ran great.
Backed it into shop, shut if off, again no crank.
Pulled starter, cleaned termials, bench checked OK.
Reinstalled, no crank.
5 pin starter relay wasn't working, cleaned terminals, still nothing.
Had an 4 pin from an 88', plugged it in, it cranked over, wouldn't start, no spark. Put original 5 pin back in, cranks over, no spark

Pulled spark plug, no spark, pulled plug going into coil, no voltage at plug when cranking. Checked all fuses, ok.

Could it be a crank position sensor?

Any other thoughts? Appreciated.

the fact that it ran when you jumped the terminal says not a crank sensor.

you have a power issue for the key in start position.
trace back the wire for that and see where you are losing voltage. could go all the way back to the key.

The only reason I considered the CPS because I'm not getting voltage to coil during cranking.

I will check the ign switch.

Any jumps I can make for a test? or just go through the Haynes schematic?

Thanks Andrew!

4 pin vs 5 pin is a little confusing to me.
not sure what wire you would have left off. and not sure why it decided to crank.

I have no short cuts for you. just disconnect at the relay so it doesn't try to crank the whole time and have someone hold it in start and start tracking connections back till you find out where it goes away.
you can start at the column if you want to eliminate the switch.

4 or 5 are RELAYS.
Not good to swap unless they are the same!

Put a test light on positive coil terminal with wire connected. Crank and leave key in on position. Should have power.
If not, look upstream according to the wiring diagram.
IF it has power, put light on neg side. Should flash cranking.

Yes, 4 or 5 ar relays, extra pin (blade) does not have a wire going to it on back
One little ditty I just remembered. When I crossed the starter terminals the second time, I was pissed off and it was dark.
I had a good light show...:) could I have fried anything?
There only the pos from bat and the pos for solenoid from relay.

RSR,
"Put a test light on positive coil terminal with wire connected. Crank and leave key in on position. Should have power.
If not, look upstream according to the wiring diagram"

Can you clarify that?

The coil has the tower post going out to dist and a plug
on bottom with with two small ga wires. I assume one of those should
be hot with key on or cranking and the of the other from CPS for trigger. Do I test those while they are actualy plugged into coil?

Thanks 1000X.

I'll look up stream today.

Check the main harness under the power distribution block beside the battery.It is a heavy harness that splits into a Y.Untape it at the Y,there are three wires crimped to one wire,think they are red and white but can't remember for sure.The connector was prone to coroding,sometimes made contact,sometimes didn't.Whether it's bad or not,remove the connector,solder and heat shrink the connection.If that is not your problem,it will eventually be one.

while it is possible, you can easily check.
turn to run and bridge the starter relay again, if it fires up nothing new is broken.

you can try the test light trick with everything hooked up. but I don't think it will tell you anything you don't already know.
you are missing power during crank, not run.

just have to figure out where it is dropping out.

X2 on what 62maxwgn said. I just had a similar problem with my sons 93 Dakota. Opened up the wiring harness from the relay box, found the red/red-white wires that were 3 into one, cleaned them, re-soldered and sealed it up. Didnt fix the problem. moved forward in the harness, and found a ground that was basically sheet metal screwed to the inner fender (between the battery and the relay box. Cleaned the ground, tightened it up. problems solved.

Laine.

SOLVED
I hope....

Cleaned (looked fine) ground to engine, and cleaned ground
to Body (actually removed paint under screw head as opposed to
just screw threads for ground.

Put test light in coil plug and it was hot,
plugged it back in and if started up.

I will head the advice on the tri wire suggestion.
There are some jumps and splices in there already before I
bought truck. Will double check

Thanks guys!!