Electrical Schematics

[GHarman]

Pete, I looked through the case cooling grates and saw a circut board like a (printed circut card) computer motherboard! There are 5 TORX screws that allow access to the "motherboard". Didn't see any gell. Will try to contact Daledozer. I am custom wired for a TACH and PYRO. Have ISSPRO gauges and gauge cans but was never able to get them hooked up. The truck was used hard while I was working 6+ days a week for many years. There was no downtime for the extras. Now that I have time the usable life of this truck as a reliable vehicle is seriously numbered. I'm not sure that it will last the 20 years that I need. Given that everything will settle out, it still needs a new exhaust and probably other maintainence work. If it will last is the big question. As you can tell, I am dissappointed, to say the least. Thanks, GregH

 

[GHarman]

Pete, I sent Daledozer a PM. Thanks again. GregH

 

[78cummins-wagon]

lets see... i'm new to the sight, and...

i dont know how anything works yet. i bought a 1993 w250 dodge/cummins, auto, club cab, LE, with slight fuel pump adjusting. it had been rolled, so i thought i'd swap the cab out with my 78 crew cab cab and short bed. that part of the conversion is done, but now i'm down to the wiring end of it. most of my things from the 93 are now in the 78, and it does start and run, but i have know gauges. both ends of the original wiring harness are still hooked up, just going through a new cab. i have absolutely no battery gauge. the oil pressure gauge pegs itself on high when i start it, and the temp gauge slowly pegs its self on hot the more of a drain on the battery there is (i. e. if the turn signals are on, then every time the light flashes, the temp gauge goes higher. ) i also only have the drivers side turn signal. the light on the dash for the left turn signal stays on all the time when the keys in the on position. the right does not work period, not even with the 4 way's on. when i unplugged the wiring harness from the alternator, 2 of the pins from the plug pulled out and i thought i put then back in the right place, but with no gauges, i'm not sure. if anyone can help, its greatly appreciated

 

[GHarman]

i dont know how anything works yet. i bought a 1993 w250 dodge/cummins, auto, club cab, LE, with slight fuel pump adjusting. it had been rolled, so i thought i'd swap the cab out with my 78 crew cab cab and short bed. that part of the conversion is done, but now i'm down to the wiring end of it. most of my things from the 93 are now in the 78, and it does start and run, but i have know gauges. both ends of the original wiring harness are still hooked up, just going through a new cab. i have absolutely no battery gauge. the oil pressure gauge pegs itself on high when i start it, and the temp gauge slowly pegs its self on hot the more of a drain on the battery there is (i. e. if the turn signals are on, then every time the light flashes, the temp gauge goes higher. ) i also only have the drivers side turn signal. the light on the dash for the left turn signal stays on all the time when the keys in the on position. the right does not work period, not even with the 4 way's on. when i unplugged the wiring harness from the alternator, 2 of the pins from the plug pulled out and i thought i put then back in the right place, but with no gauges, i'm not sure. if anyone can help, its greatly appreciated

I'm in the same boat you are. I dont understand all I know about this subject:-laf. GregH

 

[GHarman]

Used PCM

Picked one up today at a junkyard. The price grew from the time I discussed it on the phone yesterday, till I picked it up today. No returns! If it works, wonderful. If not, what can I do?

However, I do have at least one dead PCM that I would like to get refurbished. Anyone out there know of an automotive electrical shop that does this type of work and does it well? GregH

 

[therabbittree]

you don't need a pcm . . I would go with out it the earlier first gens don't use it. .

 

[GHarman]

I figured as much. However, I am not a wiring harness guru. It would take a considerable learning curve for me, to get it working. I no longer have the patience or the desire for such vehicle stuff. If this PCM doesnt work, I will have some decisions to make. Thanks, GregH

 

[therabbittree]

the grid heater can be run on a heavy duty push button switch, ... removing the fuel shut off solinoid and pulling the plunger out and then screwing the gutted shut off back in is easy, running a cable to the manual pump shut off lever is easy. . swapping speedo clusters from a junk yard truck is not too hard , hardest part is getting / sourcing the parts and swapping the cable drive and the cluster in. .

hopefully something works for you. You've had a run of the murphys...

Thanks,

Deo

 

[GHarman]

the grid heater can be run on a heavy duty push button switch, ... removing the fuel shut off solinoid and pulling the plunger out and then screwing the gutted shut off back in is easy, running a cable to the manual pump shut off lever is easy. . swapping speedo clusters from a junk yard truck is not too hard , hardest part is getting / sourcing the parts and swapping the cable drive and the cluster in. .

hopefully something works for you. You've had a run of the murphys...

Thanks,

Deo

Deo, Where or/is there a manual shutoff lever? Do I have to install one ? Where? I agree that the Shutoff solenoid would be a piece of cake. Not to sure about the charging system and the wireing of the heating grids, what about the KSB?. Like I said I am ignorant of wiring harnesses. I think I understand wiring diagrams but the actual wireing harness is a different story. Troubleshooting a fuseable link ! Wouldn't know where to start. GregH

 

[therabbittree]

on the side of your injection pump is a little lever that is spring loaded it should have nothing attached to it, with your truck running if you pull the lever back, it will shut the fuel off and stop the engine. . you'll see what I mean. Do you have a service manual? you should buy one . . often you can get a used one in the classifieds or ebay . . heck a new first gen one is pretty cheap I think $60???? . . that will help you tremendously

Good night

Deo

 

[RGramlow]

you just need switched 12 volts to the fuel shut off if it still works, go to your favorite parts store and get a voltage regulator from an older dodge with two wires to hook up, one goes to switched power and the other hookes up to one of the small wires on the alternator. The other small wire on the alternator gets hooked up to switched power, and the big wire goes right to the battery. make sure the regulator case has a good ground. Wire a push button switch in the cab up to the two grid heater relays on the left fender, just need to turn them on for 20-30 seconds when it is cold, hook both together. It isn't too hard, don't make it anymore complicated than it really is.

 

[RGramlow]

i dont know how anything works yet. i bought a 1993 w250 dodge/cummins, auto, club cab, LE, with slight fuel pump adjusting. it had been rolled, so i thought i'd swap the cab out with my 78 crew cab cab and short bed. that part of the conversion is done, but now i'm down to the wiring end of it. most of my things from the 93 are now in the 78, and it does start and run, but i have know gauges. both ends of the original wiring harness are still hooked up, just going through a new cab. i have absolutely no battery gauge. the oil pressure gauge pegs itself on high when i start it, and the temp gauge slowly pegs its self on hot the more of a drain on the battery there is (i. e. if the turn signals are on, then every time the light flashes, the temp gauge goes higher. ) i also only have the drivers side turn signal. the light on the dash for the left turn signal stays on all the time when the keys in the on position. the right does not work period, not even with the 4 way's on. when i unplugged the wiring harness from the alternator, 2 of the pins from the plug pulled out and i thought i put then back in the right place, but with no gauges, i'm not sure. if anyone can help, its greatly appreciated

I did a conversion last winter. https://www.turbodieselregister.com...s/182286-chevy-c70-service-truck-cummins.html

I might suggest not using the enginee wiring harness, just use parts of it, and use the harness from the cab only, it might be easier to all your lights and signals working before hooking up the engine. Use the sensors (oil pressure, and temp) from the 78, I think there should be a wire going to the ignition system, just hook that up to the fuel shut off solenoid. Use the voltage regulator from the 78 as well.

 

[PToombs]

78 cummins wagon, sounds like you have a serious bad ground situation. From battery should be main ground to engine, small ground to core support. Small ground strap from engine to cab, another small one from engine to frame. Small one from dash to cab.

From what I have read in the conversion forum, you did the right thing using the whole harness in the crew cab. You are using the '93 dash right?

 

[GHarman]

PCM Replaced

Replaced the PCM with a used unit off a truck that actually ran according to Steve at Denver Truck Parts. Cleaned the terminals and assembled everything

except the + battery terminal. Used the voltmeter and still have the voltage drain. Need to charge the battery. Then try to start it. I reckon the next step is pull the radio and disconnect its power supply. Check the starter wiring and then ? If it will start and run! That would be a GREAT HEADACHE out of the way. The other stuff is small potatoes. GregH

 

[TWorline]

Greg:

You should be able to reach up behind the radio and unplug it, or get a flashlight up in there to see where they hooked up the 12V constant wire. It will be the Yellow wire coming out of the after market radio harness. Just a thought, your radio turns on and off with the key correct? If so they probably have it wired up correctly.

 

[markha1]

I dont think a volt meter in series with the battery will show a short, it needs to be a ammeter, 12. 5 volts is fine for a standard battery as long as it holds at 12. 5 under a moderate load. 12. 5 volts should be fine to open the fuel solenoid. 13-15 volts with the alt running @1000 rpm hope I can help in any way I can

 

[GHarman]

Ammeter?

Like to try one, Mine died. The voltmeter shows a 6V spike and a 4V constant drain. With the key off and removed there should be no voltage drain except the radio programmer/clock as Tim has said. I will try every avenue. Will replace my multimeter this week! I have not tried to start it with the replaced PCM. It may function just fine. I wont know till Monday, after charging the battery. Thanks for your input. GregH

 

[PToombs]

Greg, I usually use a test light, if it's on, you gotta drain. I've never used a voltmeter to check for draw.

Just so you know, I just bought a PCM Diagnostic book on e-bay, should be here next week. (i hope!)

 

[GHarman]

Todays experience

Installed a new voltage regulator and a Used PCM last week. Today, I charged the battery and plugged the block heater in fer a spell. It has been cold at night, course i'm using synthetic, but just wanted everything jes so , no excuses.

Disconnected the *fuel shutoff solenoid and cranked it over fer a 30 count and reconnected the bayonet fittings on the *FSOS. Did the wait to start and it fired off pretty quick and idled beautifully! Thank YOU, LORD. I let it idle fer a while whilst moving vehicles around in prep for moving the truck. (Wifey is not happy with the truck blocking "her" garage:-laf!) I looked up at the truck and it quit! Just like somebody turned the key to the off position. I was devestated:{. So I went into the house and discussed it with my Wife. She is mad, I am mad. So I get a call from my friend in ALASKA and we discussed some things and I told him what happened. (He is not a diesel man, but it does help to voice yer headaches:-laf) We say our goodby's and I tell my wife that I think I have an idea what is wrong. I went out to the truck and grabbed the FSOS bayonet connectors and wiggled them and reconnected the battery and IT STARTED! I revved it up some and in the middle of the high RPM idle it quit again. Jumped out and wiggled the bayonet fittings (connectors on the gray and blue wires to the FSOS) and it fired up and ran again! This has not fixed the electrical drain I reported earlier but a combination of issues have been narrowed down to why it would not start and run. I need to replace those electrical connections. They are really loose and the vibration of running disconnects them ( I think). I am VERY THANKFUL that there is some progress here. This has been a learning experience, to say the least, at a considerable cost in time and finances. I am very thankful for all of the input that I have received, in all of the threads that I posted. (It could have been alot more expensive otherwise. ) They were all a big help and encouragement. Now to get this rig back on the road. GregH

 

[TWorline]

Greg:

You can sneak a pair of needle nose pliers in the ends of the connectors and tighten them up by squeezing the rounded parts down towards the flat side. Or you can take the nut off of the top, remove the double spade terminal, put ring terminals on the wires and reinstall the nut.