1996 Ram 1500 Sport, 5.9, Automatic, 4X4, 171,000 miles

Now and again this week, there are times my truck just dies as if key is turned off. It is not a dying like fuel starvation. Once while stopped at light, not even moving it died. Three times while traveling in residential area, only about 30 MPH. The first couple times it dies, there was no codes set. Once when it died, it was a rough dying- jerked around a little, it threw a code P1391. That is a CMP or/and CKP error, but I think that code got set as it was a rough dying that did actually throw those sensors off. The rest of the times it has been a smooth stopping of engine that you don't even feel and no codes. Then always starts right back up.

I can't force it to happen, tried gunning it down the road, give it heck going up this 18% grade hill, fast takeoff from stop sign, idle and can run tach up to 2,000 rpm and can just hold it there and runs smooth, also idles smooth.

About 2,000 miles ago, changed all plug wires, plugs, dist cap, rotor, cleaned IAC, TPS and something else on that throttle body, oh yea MAP and run some sea foam through injector port.

This never happened before, actually it happen just after I had someone else change front axle seals and all ball joints, but can't see how that could be any cause.

Anyone has ideas what to check? Truck becoming a pain. I must have accidentally loosen the radiator cap today crawling around looking for loose wires as when I got home after failing to make it die, water flew out the radiator cap that I just replaced about 2 weeks ago, it was loose, now I got a mess to clean up. Then hail wasted my house roof- too many things all at once!! Sorry for long post, it is nice in here and the A/C is working good and I don't want to out and clean up mess.

 

Remove negative battery cable first, and try cleaning the IAC and TB. https://dodgeforum.com/forum/dodge-r...n-the-iac.html

If that does not work, I'd say cranks sensor needs replace. If you decide to replace it , get one from the the dealer or a Standard Motor Products brand. And disconnect the neg bat cable before replacing. Also check the new one side by side with the old and make sure they are the same length.

 

Okay thanks. Since that last post I did clear the PCM by disconnecting the neg cable and turn on light switch for about an hour, believe that is what I read. Did see something about cranking or connecting post, but that sounded like trouble and i am in no hurry. I cleaned the IAC and TB about four months ago, can do it again, maybe just replace the IAC as that is a piece of cake.

Tonight after resetting PCM I went for drive and all was fine, I was thinking darn this won't ever do it when I want it to. Got home, put in park, it idled fine at about 600 RPM, tried to hold it at 1,000 RPM and it just wouldn't do it, it would fluctuate between 1,000 and 800 RPM, just like clock work, up and down 800 - 1000 and back to 800. It finely died, but no code. I tried same thing again and when it started to die, I gave it gas and engine shook and that time I did get the P1319 code, but if I let it die without giving gas, no code. The trying to accelerate just shakes everything and throws it into convulsions.

I have read the manual, I study the manual, page 403 of the manual, figure 50 is crankshaft sensor and I can't see that bugger for anything. I know it is on block near passenger side, I believe it goes stright down and most likely reads notches or something on flywheel? I may see it just to the left of distributor when facing truck. I may have to hire it done, but I know a guy who will let me buy parts and just charge labor. My back just won't let me lean over and get to the back of that engine for long.

 

IIRC you can reach the CKPS from underneath, esp if you have a auto. A bad CKSP would cause that problem, happened to me once...

 

w/battery disconnected and headlight switch OFF, the pcm will drain down and reset in about an hour.

w/headlight switch ON, it will drain down in 30 seconds.

 

Thanks, I read somewhere where you could touch the pos and neg cable together and that just sent up red flags as will as turning key to starter. It may be fine to do that, but I learned to trust that feeling when it just doesn't seem right.

 

Touching pos and neg cables together doesn't work in my experience. Using the 30-30-30 keyswitch procedure to reset PCM, BCM, TCU, ABS, and CTM (each where applicable) has always worked for me on EVERY make and model of vehicle, never had any troubles, but to each their own.

 

I vote for the crankshaft position sensor also. I had the exact symptoms you describe...twice. Search my posts, I did a how-to write up on how to replace it.

 

I may have found that #$%^& crankshaft position sensor. From underneath I found what looks like it at about 1 o'clock looking from the back toward the front on bell housing and I can just barely feel that it has two allen wrench bolts and a wire coming off that looks pinched in by the transmission tube bracket for dipstick. My hands and arms aren't small, but not large either and I don't think a person can get a wrench in there without removing some exhaust pipes. Then the instructions in shop manual said remove air cleaner intake and come in from top, look impossible coming in from top.

Anyway to make sure I really got the CKP, where does that wire from the CKP go to?

Where is that how to, the manual isn't helping much. UPDATE Found your post, looks like I did find it, anyone knows where the wire from the sensor hooks to? It looks like I may have to remove the tran tube bracket to get wire out?

 

here the sob is w/transmission out...
the lead wire goes up beside the oil pressure sensor (the shiny cylinder) and into the wiring harness to the PCM.