Engine/Transmission (1994 - 1998) Power to Shut Down Solenoid Problem

[Dave Remillard]

I need some ideas on what to look for. The other day I experienced that dreaded running out of fuel sensation and then the truck died. After poking around for a few minutes I checked to see if the fuel shut off solenoid was working correctly and found that with the key on, the plunger was not up. I was able to push it up and the hold circuit worked. After priming it I was able to get it going and drove home. Got to poking around last night and found that the coil for the shut down relay is not powered with the key on. If I looked at the wiring schematics correctly, the only thing between the relay and the PCM is a splice #169. I think the PCM is ok because of other things that work, so suspect this splice is the problem. Wondering if others concur and possibly have other thoughts on what to look for. Also can anyone locate this splice for me. It is probably obvious because the relay is only a couple of feet away from the PCM, however it would be nice to positively identify it before going any further. If by chance my PCM has gone bad, where to buy a replacement and how much should I expect to get my pockets emptied. Thanks in advance for any ideas.

 

[Joe G.]

I don't think your problem is the shut down solenoid. On your '95 the PCM has nothing to do with it.



The normal operation for the solenoid is that when the ignition key is in start the pull on (high current) coil is energized and pulls up the solenoid. When the key is released so it goes to the run position the pull on coil is turned off. The hold coil (low current) is energized as long as the key is in the run position.



With this in mind I doubt that the engine would die because of this solenoid's hold coil failing. You can test it by turning the key to the run position and pulling up the solenoid by hand to see if it holds it up.



There is a large three wire connector on top of the other wires and behind the air horn. You can test the circuits here. Pull the connector apart. Connect a volt meter to the heavy white wire and a ground. The heavy black wire is ground. Turn the key to start. There should be 12 volts when you do that. Turn the key to run. There should be 12 volts on the small colored wire and not on the white wire. My small wire is violet on my '95.

 

[illflem]

It sounds like the problem is either the blue wire from your driver's side battery being corroded or blown (it's a fusible link) or the solenoid relay is shot.

Best price for a new one is here http://www.fostertruck.com/dodge/default.htm



Problems and operation are also decribed there.

 

[Got Smoke?]

Originally posted by illflem

It sounds like the problem is either the blue wire from your driver's side battery being corroded or blown (it's a fusible link) or the solenoid relay is shot.

Best price for a new one is here http://www.fostertruck.com/dodge/default.htm



Problems and operation are also decribed there.

I second the blue wire. I had all the problems of a dead solenoid and even a new relay didn't fix it.



Was just about to order a new solenoid from Piers and found an OLD thread on here that talked about the blue wire.



Found my problem and it was fixed for FREE!!Oo. minus the $38 for the relay :-laf

 

[Joe G.]

The engine died in this case: "I experienced that dreaded running out of fuel sensation and then the truck died". That means that the start pull on circuits (blue wire, relay, etc) are not involved. The hold circuit probably did not fail either because when he pulled up the solenoid with the key on it stayed up. This does not appear to be a solenoid problem at all. Or course, there may be some intermittant problem with the hold coil but that is unlikely.



So the question appears to me to be "why did it die?" not "why won't it start?" Plugged filter, air leak, bad fuel, ... . ??? Need some more tests to find out.

 

[Dave Remillard]

The fuel filter is relatively fresh (200 mi. ), recent fuel lines between lift pump and frame, and as far as bad fuel, possible, but I had run about 3/4 of a tank without trouble. It seems like an intermitten problem as Joe states. I printed the Foster truck link electrical drawing and will hopefully have a chance in the next day or so to prove it as being Ok. I mainly was wondering if there has been any one specific known problem that this could be tagged too. I know the pull in circuit is not working and I suppose its possible the hold coil circuit is not stable. Thanks for the ideas so far. I at least feel I'm on the right path, and have a few items to check out that I wasn't clear on before.

 

[Joe G.]

Does the pull on fail when you turn the key to start? You may have to have a helper to check this for sure. Even if it does fail that should not cause it to die. I have a theft "delay" switch on my '95 that disables the pull on coil. If I accidently turn it off while the engine is running there is no effect.

 

[Dave Remillard]

Joe, That is correct, the pull in circuit is not working but the hold does. Is it posible the hold circuit experienced a momentary failure? Perhaps its going bad but just hasn't failed completely. I have seen this before in 120 volt relays where the coil wires can fail and then somehow fuse themselves back together for a short period of time before complete failure. I'm just not comfortible with a 12 volt system being able to do this. It could be a lose ground or perhaps splice. I simply will not have any time to check on it any further until this weekend. Been working killer overtime.

 

[Joe G.]

It's possible, but doubtful. You describe the failure as a "running out of fuel sensation" which sounds to me like it lost power but was still running for a bit before it died. If the fuel solenoid failed I would think that it would just quit like turning off the ignition key. Then you say you primed it. If the fuel solenoid was the problem you would not loose prime just like you don't loose prime when you turn the key off. It's just a valve to turn the fuel supply to the injection pump on or off. If there was air in the system, especially if there is air before the solenoid, the solenoid is not the problem. If it dies just running down the road then the pull on coil or circuit is not involved. That is only used when you start.



You can test the fuel solenoid and circuits. It's better to have heavy test leads for this. Pull the three wire connector apart. Test the fuel solenoid side of the connector first. Connect a ground wire to the black wire terminal. Connect 12 volts to the small colored wire (brown or violet). Touch 12 volts to the heavy white wire. The solenoid should pull up and stay up. If you think the hold coil is intermittent try tapping the solenoid with something. It should stay up. If the fuel solenoid passes this test then get a meter and test the other side of the connector. Lay the meter on the windshied so you can see it. Connect the meter ground wire to the black wire. Connect the meter signal wire to the white wire. Turn the key to start. You should see 12 volts on the meter. Connect the signal wire to the small colored wire. Turn the key to run. You should see 12 volts on the meter. If you think there is an intermittent circuit problem then wiggle the wiring harness around some and watch your meter.



If the fuel solenoid fails the test then take it off and check it some more on your work bench. It just may be dirty. Also check that the linkage on the side of the injection pump is not sticking.



If the circuit test fails then check the relay, blue fuse link, starter contacts, start connection to the relay, etc.



If it passes these tests then look at your fuel supply system.

 

[Howard Durand]

There are a couple of relays in the Power Distribution Center that are involved in fueling. One is the Fuel Pump relay and the other is the Automatic Shutdown relay. They are both controlled by the PCM.

If the fuel pump relay opened for some reason I would think it could cause the symptoms you describe.

 

[Dave Remillard]

Thanks for the great ideas and troubleshooting procedure Joe. I'll print all of this out and use everyones ideas to check it out. Hopefully by next week I'll be able to provide positive feedback on what I find.

 

[Joe G.]

Howard,



Those relays are only in the gas models, not diesel.

 

[illflem]

Joe's right, about the only things our 12 valves need from the PCM to operate is grid heater and auto trans signals. Engine doesn't even need that to keep running.

Simple way to see if something other than the shut down solenoid and it's circuits are causing the problem is to tie the solenoid up in the run position, drive around and see how it behaves.

 

[Howard Durand]

Well, that is strange since my Service Manual shows them being a part of the Diesel Engine Control System and the relays are in place in the Power Distribution Center on my truck.

After pulling my head out of the cloudy area, I realize there are no electrically operated fuel pumps in these trucks. Perhaps that is why I have found some of the diagrams in the manual to be confusing.

 

[Joe G.]

Well, just in case I was suffering from another case of the hoof in mouth, I looked it up in my manual. Sure enuff the wiring diagrams for the diesel have a fuel pump in the tank. Mine doesn't have one so I think I will complain.



I've seen some other errors in this manual. Some of them in the transmission section are the same errors as is in my '81 Imperial manual.



The wiring diagrams don't always have the right colors for the diesel stuff either.

 

[illflem]

Good. At least the dealer mechanic who dropped my tank under warranty because my truck was missing the fuel pump wasn't all to blame...



There are some pages in the back of the manual to report errors, doubt if it will do any good though as I'm sure the older manuals are long out of print.

 

[JWaters]

solenoid

I have a brand new never opened fuel solenoid kit from cummins that I can let you have for 180. 00, I paid 289. 00 for it. It is brand new and never opened . It is the upgrade kit with the large solenoid. If you are any wants it I will take 180. 00 plus shipping.



I also have one for a 8. 2 detroit diesel that cost 230. 00 that I will sell for 100. 00 new in box.



Please email -- email address removed --



thanks

 

[RBrunson]

Trouble shooting

Here is a little trick I learned years ago for checking circuits. Use one of them annoying buzzers that we all disconnect thats under the dash. They usually have male spades on them, just hook a couple wires with clamps on the ends to hook to the wires you are testing. Makes a nice loud buzz when power is applied. I find this is useful especially when checking a brake light circuit (can't see tail light when stepping on the brake pedal) but you can hear the buzz.