mr300x11
Registered User Join Date: Sep 2007
Posts: 1

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I purchased my 93 cummins 5yrs ago, havent had a problem with it till now.
couple of weeks ago the alternator wasnt charging my a/c compressor shut down and the tranny wasnt shifting right and to top it off I couldnt keep it running at a stop light without reving the engine up.
So I had a friend who is a diesel mech. he said it was the alt so he changed it it did the same thing put another one on worked perfect for 55 miles lost charge ac quit and the truck died.
I went to Dodge dealer he said it was the PCM.
Now I dont know which way to go.
Is it the crank sensor or the PCM.
What voltage or what OHMS should you have on the crankshaft sensor.
Unfortunatly it is erratic some days it works perfect and some days it doesnt work at all.
Any help would be greatfull.

 

It could also be the wiring harness that runs to the sensor. Mine rubbed a bare spot on one wire where it turns down toward the sensor at the top of the engine. It was such a small spot I missed it the first time I looked. The next time it won't charge, crank it up and slowly lift the wires away from anything metal. If it starts charging or the ac kicks on, put some plastic loom around the wires. In the past, you could get a re-manufactured computer from Autozone and Advanceauto.

 

Thanks i will check it out today

 

Also, make sure that none of your positive battery cables are rubbing a ground anywhere. A truck will run without a battery as long as the hot wire isn't grounding out and the Alt is good.

If it is the PCM, look in the sticky for how to install an old school regulator to do the job. Only 15 bucks, even if you screw the first one up.

 

Well I checked the wiring everyting looks fine.
Started the truck let it idle for 30min or so charged perfectly the the alt shut off tested the camshaft sensor still showing OHMS so i guess it is the pcm.
I thought about doing the external regulator idea but that probaly wouldnt cure the stalling problem at low idle.
or the tranny from shifting normaly.
I really dont know what else could be the problem

 

Stalling at idle is unrelated to the crank sensor problems. Unless the idle speed is just set too low, a truck that dies at idle when warmed up is usually due to a tired injection pump.

On the crank sensor - check that wiring thoroughly. The wiring fails much more often than the sensor or the PCM. And I'd throw a sensor at it for giggles before I spent the money to replace the PCM.

 

I think on Monday I will Take it to Dodge and have them hook it to there computer and see what the computer says.
I found a PCM for only $240 I didnt think that was at all bad.
I will check the wiring one more time tomorrow.
The stalling problem is another eratic thing its not all the time some weeks it works fine some weeks i cant keep it going without using both feet.
Is there a way to check the pump to see if its failing or is it getting old there is not many miles but alot of years.
I have learned alot in the past few days about my truck thanks to everyone here.

 

I hear your pain about the not charging issue, I have finally found what the problem was with this 93 that i have. Bad ECM. I have all the symptoms that you do, minus the stalling. I new a guy that had a 93 auto from this website that lives just up the road from me, i went up there this afternoon and swapped out ECM, sure enough once i put the ecm in from his truck, my 93 worked as it should, overdrive, ac, and best of all full charging of the system. Where did you find the ecm at, i now need to get one for this truck. Thanks

 

Don't forget the simple stuff also. Clean the battery connections, make sure the body and engine grounds are clean and tight on both ends.

 

I found the PCM at the dealer the part#R4746568
But the part number that is on my PCM 56026860
The dealer price is $245.00
There is a $100 core charge
I will let everyone know what Dodge says this week.

 

I chased the same symptoms for a year on my 93. Listened to everyone and ran new ground wires, changed the crank sensor, installed external voltage regulator, etc........, all with no success. Finally I shipped my PCM off to get remanufactured at a cost of $170 + shipping and guess what, everything works again!!!

 

I had the same problem minus the stalling and it was the crank sensor. They are 60 - 100 from cummins. Change that first before the pcm.

 

Well the saga continues.
I had the OBD scanner put on my truck.
It locked up the scanner every time we attached it.
The tech had no idea what the problem was so I think I will put a aftermarket regulater and see what happens.
If no change then i will change the PCM.
Thanks again for everyone help.

 

It will charge with the new regulator, but all the other problems will remain.

 

Well I turned my pump up 2 turns what a difference, a whole lot more performance off the light.
The stalling has gone away. Trany seems fine for now drove it around 60 miles today truck ran perfectly.
This weekend I am going totry and put a external voltage regulator. I would like to have the instalation instructions I found it last weekend but now i cant seem to find it here.