Ford NH 3930 Electrical issue with fuel shutoff solenoid, help please.

[Happy Gilmore]

I have a 1995 Ford NH 3930 MFWD. The fuel shutoff solenoid is not closing when turning the ignition off. I've been having this issue for quite some time. On occasion it will shut off with the keyed ignition, however most times I shut it off manually at the pump. The solenoid wire remains hot with the ignition off (checked with test light) If I unplug the wire to the solenoid it'll shut off. I was thinking possibly the ignition switch and changed it for a new one, same issue. The charge light on the cluster also stays dimly lit while running, pulled the alternator, had it tested, no issues. Battery is at proper voltage. I can't seem to think of where else to check regarding the fuel shutoff issue, I could always add a cable to the dash and shut it off manually, but I'd like to fix it properly. Any suggestions would be greatly appreciated.



On a side note fuel gauge isn't working, sender maybe?

 

[kirkawilson]

I was having electrical issues with my 1998 Ford NH 1920 last year, including the fuel solenoid. When I pulled the dash, I discovered that a rodent had nested on top of the fuel tank directly behind the dash wiring harness. The rodent had chewed through many of the wires feeding the dash. Replacement dash unit was very expensive so I cut the harness at the chew points and color matched the wiring back together with quick splices. It's working fine, so far.

 

[Happy Gilmore]

I had the cluster out last month, I had a few chewed wires, which I repaired. I couldn't see any other damaged wiring on the harness.

 

[3930dave]

Hap - have you checked out the fuel relay ?

If you don't have the schematic, try here:

http://www.tractorbynet.com/forums/owning-operating/257034-ford-newholland-3930-wiring.html

Rgds, D.

 

[Happy Gilmore]

Thanks Dave, that sounds like a good place to check, I have the 8x8 tranny with large fuse panel, does page 27 mention anything about the relay location?

 

[3930dave]

Thanks Dave, that sounds like a good place to check, I have the 8x8 tranny with large fuse panel, does page 27 mention anything about the relay location?

I usually try and scribe accurately on here, but when I said "I have one myself" in that thread, I meant a 3930, not a copy of the schematic. Put it down to not enough coffee that day....

There is a handwritten note on that scanned schematic saying "Located Behind Dash Cluster", with an arrow pointing to the Fuel Relay. I'd just follow the hot (as in not-grounded) wire back from the Fuel Solenoid, it should take you to the relay. I'd start by giving the relay a light tap or 3, to see if it just stuck - you seem to have a few Fords around the farm - you may be able to "borrow" a relay from another tractor too....

IF yours matches the linked schematic exactly, then either that alternator or something along that Alt wire is taking that Alt instrument bulb to ground (and turning it sort-of ON). The hot side of the Fuel Relay coil seems to be driven from 2 different fuses - with the engine not running, pulling both of those fuses may help you isolate what is going on in terms of If or How the Fuel Relay coil is being supplied with +12v when it shouldn't be.

Could be more damaged wire(s), but I won't be surprised if it is a mechanically sticking relay.

Rgds, D.

 

[Happy Gilmore]

Update, well not really, I had the kids all weekend and haven't made it back out to look the tractor over. I appreciate the info.

 

[3930dave]

10-4 ..... How does that saying go..... ?

"Life is what happens while you are busy planning Tractor Projects !"

It's great to chin-wag/diagnose this stuff with folks all over the planet on here, but this is one time it would be nice to be closer..... somebody needs to buy Lis a beverage, that one-time post of a schematic already got one guy's 3930 fixed - he now has headlights and a Temperature gauge that works !

Good luck Hap, let us know how this one turns out....

Rgds, D.

 

[Happy Gilmore]

10-4 ..... How does that saying go..... ?

"Life is what happens while you are busy planning Tractor Projects !"

It's great to chin-wag/diagnose this stuff with folks all over the planet on here, but this is one time it would be nice to be closer..... somebody needs to buy Lis a beverage, that one-time post of a schematic already got one guy's 3930 fixed - he now has headlights and a Temperature gauge that works !

Good luck Hap, let us know how this one turns out....

Rgds, D.

I agree wholeheartedly with all of the above. Today I ended up pulling the starter out of the 4630. It's been aching for nearly two years and finally gave up. That's what procrastination gets me. Good news is the shop took the starter today and it should be ready to be picked up tomorrow. Decided I'd drain the fuel tank and replace the faulty petcock while I was at it, of course the tank was full. The joys of 20 year old tractors. I love the older Fords though.

 

[3930dave]

I love the older Fords though.

I resemble that remark ! :thumbsup:

Rgds, D.