Truck: '98 12v 2500 QC 4x4, 122,000 miles, No starting problems ever.

Until.........
Went to work yesterday, truck sat all day, went to start up to go home and it would just fire off and then nothing, tried several times and same thing.
I'm pretty sure it is something with the fuel shutoff solenoid.

Question:

where do you start troubleshooting, what am I looking for as far as what is malfunctioning, wiring, relays, the solenoid itself. How can I tell if the solenoid is bad or if it is something else that is bad ?

Thanks
Greg

 

Turn the ignition sw. to the run position , then go out under the hood , and lift the linkage to the fuel shut off solenoid , there are 2 circuits to the lift pump , one is the pull - ignition in start position lifts the linkage to allow fuel .
The 2nd is the hold position - after the start has lifted , there is a hold that keeps the fuel system open till you turn the ignition off .
So what you are doing is helping / take place of the lift , it should stay up after lifting with the ignition on , then go turn the ignition sw. to start [ with out letting it go to off - after manually lifting ] .
Just in case , it is easier to have 2 people , one lifting & holding up the linkage while the other is turning the key to start .
If it does start and stay running after this , you need to replace the relay that runs the solenoid .
If that does not work , you'll need to start with a fuel pressure test .

 

super info John !
I'll check it out
Thanks

 

Most common solenoid lift circuit problem I've run into is a corroded blue wire at the driver's side battery.
It can be corroded under the insulation where you can't see it.
Most times just cutting a couple inches off and crimping on a new connector fixes it.

 

OK here is what I have
I don't see a blue wire off the d.s. battery (see photo) only 2 black ones besides crossover cable and red one going to fuse box


The relay on the firewall(2nd pic) has no wires going to it, one of the photos was taken from underneath the relay (3rd pic,hard to get a picture) and I can see the blades for a plug but there is no plug hanging ????


I can manualy lift the plunger when I have someone start the truck and it will start and keep running and then turn the key off and it will kill the engine, but when I try to restart it won't unless I manualy lift the plunger again.

Any suggestions?
Thanks
Greg

 

The second unplugged relay is for your fuel heater. The one on the right is for the solenoid. Most '98's don't have the fusible link, but a fuse in the panel. I'll be honest, I don't know which one it is, but I haven't looked that hard either. Most say its in a slot called spare. Should be a fairly high amperage fuse.

You can test your relay with a multi tester and some wire. Set the continuity across the big pins (30 and 87 I believe) and then power up the smaller ones (85 and 86). If you get continuity, your relay works. Put the tester on VDC, and check the heavy red wire for power. The one feeding the relay (I want to say its Red/black) should have constant power to it. If none, check your fuse. Check the small brown wire for power when cranking. This is the signal power that triggers the relay. If no power, start checking fuses again. Plug the harness back into the relay. Disconnect the solenoid plug from the relay harness. Hook it to the red wire and the other lead on a ground. Have someone crank it. No voltage (assuming you had voltage to the relay) you most likely have a bad connection or broken wire. If you have voltage, you either have a bad solenoid, or a ground issue. Check the ground wire in the harness to a chassis/engine ground. If thats good, its likely your solenoid. See if you can borrow a solenoid to try before dropping the money on a new one to confirm any suspicions.

 

 

Could be the boot has deteriorated and jammed up the works also. https://www.dieseltruckresource.com/...t-t257117.html

 

Alright.....
I could get the truck to start by pulling up on the shut off plunger while someone is turning the key and the engine will keep on running fine, until I shut it down.
It would not restart unless I helped the plunger up again.
Talked to the fellow over at Fosters (LarryB) and he felt the solenoid was good that it might be the relay.
Took fuel shutoff solenoid off and found spring was hanging up on crud , GAmes you were correct about the boot being deteriorated. Cleaned it out and applied a very small amount of grease and it's working fine for now.
I have ordered a replacement boot along with the supersized starter solenoid kit, solenoid saver diode, and a spare relay from them.
They along with you guys are very helpful and knowledgable and I thank you and freely provide resolutions to problems.

Thanks
W.G.

 

I'm pretty sure the diodes aren't required for the '98s. I had my starter hang up on me and kept cranking until I pulled the cable off. The truck had fired up, but as soon as I turned off the key, the engine quit running, just stayed cranking. That was my experience.

 

Tate
He told me that the feedback through the wire from the starter (signal wire)
would burn up the coils in the shutoff solenoid. He was aware that mine is a 98 12v

 

Dry lube is a better choice on the plunger. Grease attracts dirt and it will jam up again.

 

The feedback would also engage the solenoid too, which shouldn't allow it to drop when I turned the key off.

 

I use a pto cable it has never rotted off, or burnt any wires. Take that solenoid thing and throw it under the tree in the back yard.

 

Or mail it to me. I have a tree to put it under for you. Or I will just put it on an engine of mine.