Engine/Transmission (1994 - 1998) Trouble with truck

[CKHeller]

Hi Guys,
Some time back my speedometer, Odometer, tachometer, a bunch of idiot light went out and at the same time my battery stopped charging. I took it to my mechanic who us usually pretty good but I think he is beyond his scope this time. I did a search here and made some suggestions. He has put in a new alternator, replaced the ESS, and another sensor, replaced something in the ignition switch and spent hours tracking down the problem but to no success. Now he wants to replace or repair the main computer but something tells me this isn't going to fix the problem and is going to possibly cost more than the truck is worth. The key trick doesn't work because the dash is partly out. My truck is a not too gently treated 1994, 2500, long bed, manual transmission, 4WD with a few upgrades that the former owner put in including a new air intake with one of those hourglass shaped cleanable filters. There are no other upgrades that I'm aware of that involve the engine. I don't like driving it like this and don't really want to change mechanics and start over. Does all this make any sense to anyone, can you tell me what to suggest before I take it back to him?

Kru Heller
Powhatan, Va.

 

[Missouri Mule]

If the PCM (in 94 and 95 it was called something else) could cause most of those problems. I would check grounds ment for the computer and power supply to computer. Computer would supply ground and power to some of the components he replaced.
Their was one member who lost tach, odometer/speedometer,volts and it was the vehicle speed sensor( located at rear of transfer case) but his dash idiot lights still worked as I recall.

I would pull the instrument cluster out and make sure the connector is in tight(some times they vibrate loose) you could check all grounds for dash. Check all fuses and relays (fuse box and PDC).

 

[CKHeller]

Bill,
Thank you very much, I will pass this on to my mechanic. He has already checked the fuses but I'm not sure of the relays. I hope it is one of these things. If anyone has any other ideas I hope they post them soon as the truck needs to get back to him sooner rather than later so we can settle our accounts. I really need this truck, it has been a very good, reliable truck for a long time and I need to get many more years out of it. It only has a bit over 170K on the clock. I regret that I can't do the work on it any more. I never was a mechanic by any stretch of anything but became a fairly reliable parts changer. But right now I'm recovering from a knee replacement and it will be months before I will be able to do that again. Again my thanks.

Kru Heller
Powhatan, Va.

 

[surfbeetle]

There's a comment about this in the current TDR print mag in the 2nd gen section. It's either the crank position sensor or the computer (PCM). If the sensor is bad, the PCM won't know the engine is running and won't signal the alternator to charge. If the PCM is bad, then it doesn't signal either. The magazine says to try cooling off the PCM with a bag of ice to see what happens. In that case, their issues occurred in warmer temps.
Craig

 

[CKHeller]

Thanks Craig, I absent mindedly let my subscription lapse. I've renewed it but haven't gotten my next issue yet. When it comes the article will probably be helpful to my mechanic. Sounds like he may be correct and I need a new or rebuilt computer. I guess it is what it is. Thanks again.

 

[PDM]

I believe members can view electronic issues online now. Perhaps this will help avoid a delay in getting your truck fixed.

 

[CKHeller]

PDM - Thanks. I didn't know about that. Are you and Craig referring to the short section on Pg. 74 in Jim Andersons section? That was helpful but all I could find in the issue on line. I don't want wait for my next issue to arrive and it might be issue 81 which I see on the website has just been mailed. I don't know how long it takes to get he wheels turning again after a subscription has lapsed. Thank you for chiming in.

 

[surfbeetle]

It was just a short section of posts that they printed from the website. Basically it was stating that a way to test the pcm was by monitoring the temperature and use ice to cool it down if you are having the issue as well as checking the crank sensor. I don't remember what page it was on but it was in the 2nd gen 12valve section.

 

[Bill Stockard]

Here's a link to that thread: https://www.turbodieselregister.com/forums/showthread.php?242887-COLD-vs-HOT-No-Problems-vs-Problems

Bill

 

[CKHeller]

Thanks guys, I copied all of this to take to my mechanic. He is a really good guy that has never had a problem fixing my truck and isn't afraid to say that he doesn't understand something. I respect that in a tradesman and apparently so do a lot of others in this rural community, he was too busy to take my call earlier today. I was trying to find out what other sensor he replaced other than the ESS. Is the ESS also called the CPS or are they defiantly different sensors? I hope I don't have to replace the PCM, it sounds a like a lot of money. I also want to once again thank everyone that chimed in to help me, this is a really great group, this isn't the first time I've gotten guidance here.

 

[Missouri Mule]

Yes the ESS (Engine Speed Sensor) CPS (Crank Position Sensor) are the same in the 12 valves(Dodge calls it ESS and Cummins calls CPS).

Has he checked the instrument cluster connector?

 

[CKHeller]

Hi Bill, Yes he has pulled the instrument cluster and checked all the connections. I was afraid of that, ESS = CPS, but was hoping there was going to be a simpler (read less expensive) solution. The truck goes in next Monday along with my trailer (just needs an inspection) for the next level of work. Thanks for your input, these kinds of problems can be frustrating because there are so many things it could be from any one of many components to the PCM to a short or failed ground. It would be so easy to miss something simple that any and all ideas are worth checking into. Thanks again to all who helped, I really appreciate this group.

 

[surfbeetle]

What was the end result on this? My truck started doing this today. I guess I'll start with the CPS since I'm assuming it's the cheaper part. Sadly it is hot in southern California right now so I fear it's the PCM.