Engine/Transmission (1994 - 1998) Fuel heater relay

[46mech]

In the start circuit, does the fuel heater and or fuel heater relay have any effect? Looking through the shop manual I'm not seeing that it does, but I'm wondering if there's somewhere in the book that might show me otherwise.



I'm asking because I've been having the all-familiar "no start" symptoms of the fuel shut-down solenoid and/or relay. It started as an intermittent, or occassional, problem and now seems to be most prominent with the cold temps because it didn't want to start this morning and doesn't want to start now, but the wife did start it today when it was warmer. I've verified that when the ignition key is moved to start, the plunger on the solenoid doesn't move up. I hear the "click" and I suppose that's the relay?



So anyway, I plugged in a new relay from FosterTruck.com and still got nothing. I then plugged a new solenoid into the harness connector, but didn't have it bolted up because I was hoping to op-check the solenoid. I turned the key to start and still got nothing..... no movement of the plunger.



Regardless, if I'm able to lift the solenoid plunger up, shouldn't I be able to start the truck once the solenoid is up? 'Cause it didn't start then either.



The only thing I've done recently in the start system is, a few weeks ago I replaced the starter contacts and plunger with LarryB's starter contact kit.



I'm considering replacing the fuel heater assembly, simply because it's the original heater assembly and I know the pre-filter is in there and it could be pretty dirty; although it probably isn't a culprit in my current situation. Does anyone have an idea on the cost of this thing? Is it just a dealer part or is it better to go to Cummins?



What am I missing?



Thanks

 

[Joe G.]

The fuel heater and fuel heater relay should have no affect on the fuel solenoid failing. The next thing to check is the blue wire on the positive post of the driver's side battery. That is a fusable link. It tends to corrode and start doing what you are seeing. The nut holding it on the battery post may be loose and doing that. The blue portion of the wire goes to a splice to a black wire that goes to the fuel solenoid relay.

 

[46mech]

Thanks, Joe. I'll check that out.

 

[46mech]

O. K. , I'm at a loss.



I replaced the fuse link with a new 16ga. link altogether, just to be on the safe side. The end at the terminal looked a little corroded. I still can't get the fuel shutdown solenoid to raise up when I turn the ignition key. I can't even get the solenoid to stay up if I maually lift it. That means there's no electricity getting to the solenoid, right? How far do I have to turn the key before that solenoid gets its juice from the relay? Just to the point of getting the three idiot lights below the A/C control knob?



I pulled the fuel shutdown relay out and did the bench test according to the shop manual and it works fine. At one point in all these attempts, the truck did start, but only when I manually lifted the solenoid (the key was turned)..... new solenoid and new relay. Now I'm getting nothing at the solenoid.



Just in case I thought I might dealing with a battery issue, I did put the jumper cables on it from the wifes car. Bear with me, I'm electronically challenged. lol



Thanks

 

[Joe G.]

The ignition must be in the run position to hold up the fuel solenoid. It sounds like it's time to get out a meter to find out what is going on. You may have a bad connection some where. Or a bad ground. You will need a wiring diagram.