Bear with me, "story time", Long post/ but want to lay out all the info I know, that led up to my current issue.

It's been a while since I have had a crank sensor issue on a Magnum engine...... but I think I might, right now. Intermittent at that.
96 Dakota, 318, 4wd, 236k miles.
It has been dead solid dependable the last 4-5 years and 70k+miles that I have owned it, engine wise. I have had many other Dodges over the years (have never had anything but !!!!)
I have had 1 problem with it running/starting in that 70k+ miles I have owned. The notorious splice bit me about a year ago. I found it readily, and fixed it easy.
Well, over the past week I have been working on it, ( truck is showing its age)
The beginning of this has nothing to do with current issue, just telling what led up to it.

Started out, I had it sittin in the yard attached to my utility trailer, it had sat a week or so since I last drove it at that point. (I have 2 Dakotas, had been driving the other one more lately) . As I said, this one's showing its old age, so I'm "saving" it for its 4wd capabilities for winter, as I drive 70 miles a day largely on country roads, sometimes I get called back in, at weird hours/ due to my job. This truck has GOT to go in the worst of weather. And it usually does, without complaint.
so this year I haven't been driving "as" daily as I used to/ though I still like this truck better than my '99 2wd 3.9 truck. I have a few yards I mow, besides my own, each 30 miles away in opposite directions from home. Whenever I have to go mow or pull my trailer I take this truck. More power for trailer than my weezy 3.9.

Anyway, I had it sitting in my yard/ connected to my utility trailer. I got into it and went to move it, so I could collect leaves and burn them. (yes I can still do that here)
When I went to move, the brake pedal went to floor/ and "BRAKE" and :ABS" light came on. Checked it out, and ended up needing a new master cylinder. Again, up til now, this truck still had its original master cylinder. so I didn't feel bad about having to replace that.
I had my wife in the truck pumping the pedal for me, while I had it up on the lift. While finishing the bleedout of the lines, I actually watched one steel brake line blow, while bleeding. (yes I have my own 2 post lift, right here in my home garage) So I replaced ALL of them. Cut, flared, bent new lines from front to back, side to side. Also had to do new wheel cylinders, because the bleeders snapped (they were otherwise fine, before the brake line job) the one that blew, was the one that goes front to back, blew 1" behind the flare nut/ where it screws into the rear rubber line at the frame. I cringed when I spent the cash, but have come to love the hydraulic flare tool that I have (yes I do that many brake line jobs, both around here and at work)
While I had it up on the lift I decided to check out the one issue this truck HAS had for a while. Sometimes would not start in "PARK" I had to go to "NEUTRAL" and it would always start right up. Always.
I went to adjust the linkage rods, had to heat up bolt on adjuster with "Bolt buster" flameless inductive heater. In the process I melted out the shift lever bushing at the frame end.
I found the real issue with starting in Park, somehow the lever came loose on the trans itself, I had an inch of play right at the trans itself. Tightened that up, put in PARK from underneath, and it started right up. Like it used to. I got my new shift linkage bushings, got them installed, put the shift rod back in, tightened adjuster bolt on the linkage, and THEN, my starting and running issues, started.
Went to fire it up, and it would crank and crank and crank but no fire. All I did between it starting and it "not" starting, was to pop the shift rod back into steering column and the bellcrank that goes from the frame to the trans. it started for maybe 15 sec and quit (died), I had released key and my hand was maybe 6" from key switch. then the crank-no start began. I cranked enough the battery was starting to go low. (battery never did die completely) no fire.

1st thing I did was to play "musical relays" Didn't help.
Rechecked my "splice" repairs from a year ago. Still fine.
Thinking I "bumped" something I tried shaking the harness around that notorious splice and cranking. Could not do both at same time "because my arms aren't long enough to reach".
Sprayed gumout in throttle body. No change.
swapped out known good coil with one I had laying around. No change. Hooked original coil back up.
About this time I realized I had no "CHECK ENGINE" light lit up on dash. Tried key dance, and Check engine light was dead.
Shook more wires including crank sensor wires. All of a sudden I heard fuel pump buzz and it started. and I noticed I now had "CHECK ENGINE" light, while cranking again/ about same time I realized that "oh I guess I wasn't previously hearing the pump run". I don't remember which wires I shook or in what order, I think I shook the crank sensor wires last before it started.
I took it for a 10-12 mile drive in the country near the house to test out my work on the brake system. About the time I was satisfied the brakes were in fact "FIXED" I went home and shut the truck off. Started right up. Repeated 4-5 times. Started right up like usual each time. Cool. But I know the no start will happen again, I despise intermittents. and just not a fan of electrical issues anyway.
got home from work today. (Drove the 99 Dakota to work, left this one sit outside at home--- it had been in my garage on the lift for the previous 4 days) I got home, went right over to the '96, stuck the key in to see if it would act up. I cranked, it went about 15-20 sec no fuel pump buzz, no check engine light. About 20 sec into it the check engine light came on and it fired right up at that point. Check engine light NOT on while running. Key dance shows only "12" and "55". was hoping it would catch the problem and save the code. During all of this, I never disconnected the battery. I brought my scanner home from work for the weekend "just in case". but if it does how I think it will, while it is in this funk, it won't talk to any scanner til it "comes out of it".

Now a question (the part I don't remember, from when I Magnums ruled the roads and I worked on more of them) I am thinking the problem is in the crank sensor (I did wiggle those wires and tugged on them a bit, pulling the wires from the sensor "away" from the sensor, not so much at/around the crank sensor connector to the harness.) I don't quite remember/ but I'm thinking that was the last wires I tugged on, when it came out of its funk/ and decided to start.
as far as I know, that crank sensor is the original from 1996. I did overhaul the trans when I got the truck (which was why the past owner sold it in the 1st place, trans went out) truck had 160-some thousand on it when I trailered it home with trans and T case laying in the bed. It's been a fantastic truck for me, ever since I rebuilt the trans!!
But when a crank sensor goes bad, that will kill spark and the fuel pump, right??? Or should I be looking at the "notorious splice" yet again?
Oh/ and I did do a complete tuneup (cap, rotor, wires, plugs) within the last 3000 miles or so. I do this "automatically" on my vehicles around every 30K miles or so. "just because". and I always use the "good stuff," not the economy grade. When it runs, it runs great /so this is NOT a basic "tuneup" issue.

 

I'd check the connections to the ECU first!

Even a bad crank sensor SHOULD light up the CEL when cranking.

RwP

 

This would be a good place to ask about that famous “splice “. As I understand it, these are the wires leading into the bottom of the engine compartment fuse/relay box??

And somehow the wires corrode, fray, come apart, all of the above?

So for Dakota owners who have never encountered this problem, are there preventative measures that can be taken BEFORE the problems occur?

 

Already been dealt with a year ago (the splice)

 

That would be really weird as I was never anywhere near there, master cylinder is on other side of engine compartment, was look at stuff I might have disturbed first.

 

I read that. I’m just momentarily hijacking your thread to ask about that splice since I have heard about it many times on this forum.

I replaced my crank sensor a couple years ago as part of my journey that ultimately led to the REAL problem. It was the micro processor in the PCM. I recall that crank sensor wasn’t the easiest thing to access. Not a lot of room and running the wire wasn’t a joy ride either. But it was doable and I’ve had worse jobs. I might have used the old wire as a fish tape to run the new wire.

 

Like you before a year ago I had only heard of the splice that goes bad on these trucks. I've had several. A 90, an 89, a 94 then a 93, 92 and this 96. All Dakota's. When I found mine the actual (former) connect was a pile of greenish white dust. 3 or 4 wires all go to 1. I split mine up, 1 wire to 2, and then each of those to 2. Crimped soldered and heat shrink covered after that.