98.12v keeps shutting off while driving.

[Tony R]

Started about 2 months ago. It would do it once every couple of weeks. Would be driving along and it would just die. I push the clutch in wait till the rpms hit 0 and it fires right back up. There other morning I was going to work and it died at the stoplight. I would restart and it would die again. It did this several times then finally stayed running then died two more times on the way to work. I ohmed out the solenoid and I got the same readings on it as I did a used one and a brand new. I then wiggled the wiring harness around while I had the meter on it and couldn't get the slightest indication of a short or a broken wire. I cleaned all my battery connections and the truck did great for about a week and then yesterday on the way home from work it died again and started right back up. Anybody got any thoughts. I'm kind of starting to lean toward a ignition switch.

 

[95cummins5.9]

Started about 2 months ago. It would do it once every couple of weeks. Would be driving along and it would just die. I push the clutch in wait till the rpms hit 0 and it fires right back up. There other morning I was going to work and it died at the stoplight. I would restart and it would die again. It did this several times then finally stayed running then died two more times on the way to work. I ohmed out the solenoid and I got the same readings on it as I did a used one and a brand new. I then wiggled the wiring harness around while I had the meter on it and couldn't get the slightest indication of a short or a broken wire. I cleaned all my battery connections and the truck did great for about a week and then yesterday on the way home from work it died again and started right back up. Anybody got any thoughts. I'm kind of starting to lean toward a ignition switch.

The solenoid on the firewall possibly. Or the wire from positive terminal to the fuse box.

 

[Tony R]

I dont think the relay on the firewall would have anything to do with it. The start and hold part of the coil is a completely different circuit.

 

[jkretzer]

I had this happen years ago, turned out to be a loose power wire under the column right behind the steering wheel. that was my issue

 

[dieselbeef]

AT THE BTM OF THE STEERING COLUMN IS A BIG WHITE PLUG...I kicked mne or something and it was just loose enough to do this same thing...

 

[BigPapa]

It's been 6-7 years since I had my '95, but if I remember correctly, one or both of these relays works the "Hold" side of the fuel solenoid.

 

[Tony R]

I'm not sure if 95 is the same as the 98. My wiring diagram doesn't show it going to a relay just a 10 amp fuse in the dash with a couple things tied into the circuit. I'll check a couple of these mentioned above out and report back. Oddly enough before it started dieing I would be going down the road or coming to a stop and I would lose oil pressure. I hooked up a mechanical gauge and finally one day got it to act up. I still had 30 lbs of oil pressure but the gauge had dropped to 0. I researched a little bit and seen where some say it could need refreshed where it basically turns the gauge into a idiot light. It hasn't acted up since about a week before I cleaned the cables.

 

[BigPapa]

Here's the '98 Fuel/Ignition System circuit diagram:

And here is the '98 PDC. It's one or both the relays boxed in RED.

 

[Tony R]

I pulled the asd relay while it was running and the truck kept running. I shut it off and restarted and it fired right up. Not sure what the asd goes to.

 

[BigPapa]

Automatic Shut Down

 

[Tony R]

Correct but it doesn't shut down anything. The truck still.starts and shuts off as it should with the key.

 

[Tony R]

I changed the fuel filter on the truck. Not that I thought it was the problem but because it was due for one. The truck ran flawless for three weeks and now it started acting up again. Now it usually dies in the first 5 miles after setting either overnight or while I'm at work and it has been taking 5-7 tries to get it to run again. It starts then dies.

 

[Tobin]

Tie up the shutoff solenoid just to rule it and associated parts out. If that doesn't fix it, then you know it is fuel supply or IP related.

 

[Mudn_1]

Tie up the shutoff solenoid just to rule it and associated parts out. If that doesn't fix it, then you know it is fuel supply or IP related.

This or when it shuts off, dont try to start. Pop The hood and see if the solenoid is down.... That would at least tell you if its something mechanical or wiring.... my vote is a weak solenoid or a wiring issue if it works sometimes. Low batteries can cause this. Also the wire coming from the battery is a fuseable link, I have been through a few of those too.

 

[jasonc]

I changed the fuel filter on the truck. Not that I thought it was the problem but because it was due for one. The truck ran flawless for three weeks and now it started acting up again. Now it usually dies in the first 5 miles after setting either overnight or while I'm at work and it has been taking 5-7 tries to get it to run again. It starts then dies.

Your either sucking air and the fuels bleading down, after that description. Like was said, just pull over after it stalls and see if the solenoid is still pulled up. If it is electrical isn't the issue.

Check your overflow valve, if the spring has broken it will blead down like what your describing also.

 

[Tony R]

Mine dont have the fusible link. It's a 98 model. I would think if it was sucking air it wouldnt start as easy as it does. Batteries are almost new and turn the motor over just fine. I wondered about electrical part of it. My radio never flickers or anything.

 

[Tony R]

I checked everything that was mentioned above plus went over everything under the hood again. I cant get the voltage to drop any by shaking the harness or wiggling on the connectors.

 

[Big Blue24]

Next time it dies, leave key on, pull over, pop hood latch and visually inspect the shutdown solenoid. I'd wager the shutdown solenoid will be down, in the off position.

From there, I'd pull out a multimeter and see if the keyed-on 12v power at the 3 wire shutdown connector is still showing positive 12v. If yes, I'd change out the shutdown solenoid.

 

[Tony R]

It just done it about a hour ago. I pulled over and popped the hood and the shutdown solenoid was down. I'll put my meter in the truck tonight so when it does it again I'll check. I ohmed out three different solenoids I including the one on the truck and they all read the same. So that's why I was thinking this is good. I tried to push it up but it wouldnt hold. Maybe its breaking down and dropping out.

 

[Tobin]

It just done it about a hour ago. I pulled over and popped the hood and the shutdown solenoid was down. I'll put my meter in the truck tonight so when it does it again I'll check. I ohmed out three different solenoids I including the one on the truck and they all read the same. So that's why I was thinking this is good. I tried to push it up but it wouldnt hold. Maybe its breaking down and dropping out.

You could rig up light to the hold circuit and watch it when you drive. If the light goes out, you know it is loosing power, if it doesn't go out when it shuts off then you know it is the solenoid.