Its been going on almost 3 weeks now, and still no go.

Latest update as of today, I have it over at a shop that does electrical work only. the guy there has traced all the wiring to the computer and it checks out okay.

Now he is saying that where the crank sensor apparently works as a magnet or like one picks up signals from some gizmo on the crank and it not doing that. So in short all the transmission shields have to come off to check it and if this whatever it is has come off then it has to be replaced.

Sounds to me like time to seriously consider parting this truck out, I don't want to get buried in it.

1994 Ram Laramie SLT 5.2 Magnum 2 Wheel Drive. Engine has 20,000 miles complete rebuild, trans has 53 K since complete rebuild with new rad and exterior cooler. PW/PL/PS/PB/P Seats/ Dash is not cracked new shocks this year new calipers, new brakes 8 ft bed, speedo is in miles truck came from the U.S. Mostly all the sensors have been done, except Computer and it checks out okay.

Anyway thats about it I think it about time to pass it on truck is my avatar.

 

Crank sensor is basically a hall effect switch. When metal is nearby, it changes state (open to closed), when no metal is nearby, (void in the flywheel/flexplate that the sensor reads) it will change state to the opposite. Computer uses that signal to determine ignition timing. The flywheel/flexplate itself really can't have anything wrong with it, the sensor itself can indeed fail though. Especially if the engine/trans have been removed with the sensor still in place. They are quite easily damaged.....

 

The shields or cover on the transmission does not have to come off. It is behind the head on passenger side and is held on my two bolts. 1/4" allen wrench will work to pull it out or a 7/16" hex head. Not to difficult of a job.

Looks like this:

 

The garage has already put 2 new crank sensors on the truck. the first never gave a reading, so then the second new one was installed, and still couldn't get a reading.

I then had it towed to a shop where this place specializes in wiring, he now claims that the metal gizmo which gives the crank sensor its reading has either come off or is corroded. therefore not giving a reading.

Further he told my mechanic that there were some shields that had to be removed to taje a look see if there is a problem inside with this metal piece that the crank sensor gets its reading from.

I haven't got a clue as to what all this wiring B/S is all about, so I am at the mercy of the person that finds and fixes the problem.

As for the transmission it was totally rebuild at 153k, and now there is 215k on the truck it ran perfectly fine up until recently.

I have been passing all of the information onto my mechanic that you guys have fiven me here, and he has checked most of this. He runs a small garage and this guy has patience like is really rare. Anyway thats where I stand on this one at this time.

 

Do any of you have a pic or diagram of where the crank sensor picks up it connection from?

 

In you're first post you asked for the pcm number for your truck, I spent some time looking at pcm numbers last night and came up with a short list of non inter-changeable pcm's. Seems 94 is very picky on its pcm's. So can I please get your currant pcm number.

I have a thought but will need the input from other members here, Can you plug in an other CKPS and trigger it with a magnet or a piece of steel?

 

Should be notches in the flywheel/flexplate that the sensor reads. Pull the sensor, and use a mirror to have a look.

I would be curious what brand sensors they are getting..... these trucks are notorious for not really liking the aftermarket sensors.

 

I am always to slow to respond, that was my suggestion, bench test one of the other cps to verify. And I would think you should be able to rotate the engine down to where the flywheel is visible through the bottom bell housing sheild and inspect the cps trigger that way. Am I wrong?

 

Yes, the crank sensor can be checked with metal passing in front of it with the correct voltage applied.

 

Ok thank you,

So if he was to plug a new ckps into the trucks wiring harness supply power via the key and pass a piece of steel by the tip of the ckps it should trigger a spark at the ign coil. I do this kind of test on other motors but not on a automotive aseptic, will this in any way damage his pcm?