Hello,

Well Ive got a problem. I have a friend with a 1997 dodge cummins SLT. the truck is a 2 wheel drive super cab with an automatic transmission Cummins 12 valve. The truck is a ranch pickup and has seen 100K worth of rough roads and severe use. My problem stems from trying to fix the fuel shut down selenoid. A few weeks ago while feeding cattle the truck was shut off, when they tried to start it again ,,it would just crank. So they lifted the shut off selenoid and it stayed in the up right position with the key on, and allowed them to start it to get it to the house. So for the past few weeks they have been using a rope and a little pulley to pull up the lever on the injection pump after the key is turned on. The boss wants it fixed and is tired of pulling the rope and then starting the truck. So I began to diagnose by using a test light and working backwards from the selenoid to establish where the short is. I must also add that 2 yrs prior to this the relay for the fuel selenoid went out instead of just going and buying anew one, they cutt the wires loose and put a selenoid in place of the OEM relay . After trying to find out what was wrong with it and testing i removed all conectors and cleaned and reinstalled them and cleaned the batteries because they looked like the poles had been covered by white snow. FOr all my toils now the Speedometer, Tachomter will not work and it seems the alternator does not charge the batteries. Also the Check engine light, Gen light, wait to start light, and the Water In fuel light are all on. on top of that the transmission wont lock up and go into overdrive. The radio siganl lights and wipers all still work. Everything my book says (HAYNES DODGE 94-99) point to the PCM. I think it is fried As I have left the cables unplugged for up to 30 minutes and it does nothing to help reset it. If any one has any info on how to resett one and clear the problem please let me know as I am going to have to find an ECM for 1997 dodge SLT larmaie with an auto tranny. AS for the fuel shutdown mechanism I have tested it by jumping the 12 volt current through its connection at the relay/selenoid and it will lift the lever. Prior to these problems no warning lights or trouble has been seen. Sorry for the long explanation but i need good opinions based on all the varibles.

Thanks TY

 

Shutoff solenoid problem sounds like the blue wire at the driver's side battery is corroded though under the insulation where you can't see it.

Your PCM is probably OK. Problem is likely the engine speed sensor or it's wiring at the front of engine lower pulley.

 

Yep, that is what I am starting to figure out from reading through past posts. This truck has been patched on and mistreated so many times I am suprised it run as good as it does. I think I will repalce the blue wire with a new one and check the Speed sensor for continiuty. I'll post my results when i have lined it out.

Thanks for your reply. Any other info would be greatly appreciated.

 

Well, No such luck, I checked the blue wire from the battery pole, and I found good current to it before and after it conects to the red wire, so i am thinking there is short in a connection somwhere between it and the Selenoid, However the real problem I am still worried about concerns the PCM functions. I checked the engine speed sensor and it's wiring I found that with the engine running there is no current going to or from the speed sensor. I even closed the female connectors tighter so that they would it to make good contact and still no Tach siganl. I have checked all the realays and fuses and everything seems to be working. The same results still apply. No tach, No MPH, check engine light on, Gen light On, Wait to start light stays on, Water in fuel light stays on, and Tranny temp light stays on. Alternator still does not charge batteries.

 

Check the power and ground points at the PCM.

 

If possible find someone to swap PCMs with before you go replacing it. Of the many people I've known who have replaced PCMs, even as recommended by the dealer, their problems didn't go away. The problem is most often bad connections.

 

Sorry infidel , but I've replaced many computers [ when bad almost 99% were GM ] since they have been putting into cars & trucks , in almost all cases when there was a bad computer , it was something out side of it that killed it [ usually one of 2 things , a bad computer ground { then the computer finds a grd. internally , dead short - killing the computer } the other being a device outside of the computer , such as anything with a coil ie. relays ] .
So before replacing a computer , back probe every circuit at computer connector for resistance / power , this is the tricky part , finding the spec. values - how much voltage , low resistance at grds then what resistance at sensors & actuators .
After that it should be OK to install / swap for testing - this is where the manuals say replace with know good part & continue testing .
But I do agree that the problem is almost for sure out side , with the stuff on the battery cables , thats a big clue where to start .

 

Check the 150A fuse under the hood at the front ( I think) of the fuse box. It bolts in. Could be the cause of several of your problems.

 

For the fuel solenoid, it could be the relay that went bad. On mine the relay is located on the fire wall toward the drivers side.

 

Well we i have checked all current and ground wires to and from the PCM. It is definatly getting power but not putting any out. I am forced to find another PCM for the truck. I was wondering if anyone knew which one is applicable for this truck. Turns out it is a 96 model not a 97 as stated before. There is no Data link port under the dash on the drivers side, so that tells me that it is an older version like what came in the 94-95 trucks. Any how the truck is a 2 wheel drive Automatic trans, extended cab, SLT. I was hoping to find one in a salvage yard and have found many. I just want to make sure I get the right one. Any Expereinced Info or good opinions would be greatly appreciated.

thanks Ty

 

I am going through a very similar thing on my truck as you are right now. I have a post over on tdr(my member name is eklem) about it. Like you, I haven't resolved the problem but have found out some things.

Have you looked at the number 9 fuse? It powers a ton of stuff including a lot of your relays and the ecm. If this 10A fuse is bad, you will lose you tach, speedo, wts light and a few other things. It also powers the two relays for the fuel shutdown solenoid so the problems could be linked.

Good luck.

 

Yea that was the first order of business. I have gotten so frustrated that I pulled every fuse out of both boxes and checked them. I also cleaned the batteries and tested all the fusible links in the system that are descent to talk about. I also still haev current that will hold the fuel selenoid in the run position. I have tested all the grounds and have power to the PCM. But i do not have any juice or current of any amperage to any of the engine sensors. I am going to bite the big one put a computer on it if I can find one salvage for less $$$$. The truck is old and in rough shape. If it could charge the batteries without the PCM we might just get by, hell of a way to treat one but I don't own it I am just helping out. Thanks for your input though and I will be sure and post or PM you and let you know if my deal works out and Why. If i find another PCM and you need it I will let you know as they are not easy to find unless you buy a new one 800 from dodge.

 

I've been out of the buis. for about 5 yrs. , but there were reconditioned computers available from some parts house's ,
And some came with a check list , for checking important circuits , before putting in , If you do not remove the seal over the connector , then check the list & find a problem , a good parts house will take it back , so what I have done is only buy from a source that sends a check list with the computer .
One thing that has been coming to mind reading your posts , is that Chry. had been using an external power control [ sometimes called ADS , auto shutdown relay ] , if no power to sensors , but check at back of computer , with a wiring diagram , some have .5 volts to sensors , some may be 12v to actuators , one thing to remember is that computers controls the ground side of any powered device that computer operates .

 

This can be done for about $10, just disconnect the wires from the alternator and install an external regulator. Top wire of the triangular plug must go to 12 v+ switched source, the other two wires are interchangeable. Any 12 volt regulator will work, the one in the picture may not even be available.

 

Well I thought I would give every one an update. IT seems so often that lots of threads are started but no one finshes them to tell you what fixed it. We finally found a computer from dodge $$$$$ that would work and swapped it into the truck......Still have the same problem NO tach, No Speedo, No OD ( OD light on ,on switch) WIF light ON all the time, WTS light on all the time, Tranny Temp light on all the time, Tranny starts out in 3rd unless you manually drive it, and OH it still does not have any input from the computer to the ESS .5v. I also have power to the computer and ground. I am thinking there is a wire short between those sensors and PCM. I know that my ground wires are good to the sensors as i have checked them. Dodge mechanics here offer no good advice either other than to change the computer. I was wondering too I read where a computer will not work unless the VIN is programmed into it.???? is that true ? if so then the computer we found would have to be programmed for the truck. I have also read where a worn ignition switch will cuase the same problem. I would love to hear what you guys think.