Engine/Transmission (1994 - 1998) Fuel Shutoff Solenoid Electrical Issue

[BlameCandida]

A few years ago my fuel shutoff solenoid (1998 12v, manual) went out, and I just replaced it with a PTO cable as many on here have. I put in a FASS pump this weekend, and found all my old solenoid parts and a LarryB relay I had bought some time ago. I figured since I was already working on the fuel system, I might as well try repairing the solenoid. I swapped in the new relay, and then checked the voltage at the connection. I have 12 volts between the GROUND and HOLD wire, and sure enough when I push the piston into place (with the truck in RUN), the solenoid holds it up. However, when the truck is in RUN, I have 1.5 volts between GROUND and PULL. When I switch to START, the voltage (slowly) increases to 5 volts. I assume I should have 12 volts.

I looked in the factory service manual, and followed the circuit to the solenoid. Power should be flowing from fuse 9 in the PDC (checked out good), through the closed relay (just replaced), to the PULL wire of the solenoid. And if I get 12v between HOLD and GROUND, I know the ground is good.

What do I check next? Thanks.

 

[fest3er]

Check your starter control circuit. PDC fuse 2 also supplies power to the fuel relay via joint connector #2. There's a chance the control side of the starter's solenoid doesn't work quite right. And a chance the engine starter motor relay in the PDC don't close completely. Joint connector #2 is supposed to be in the PDC; it might be dodgy.

The fuel solenoid control and starter control circuits seem to be interconnected. See 8W-10-10, 8W-21-2, 8W-30-26.

(Say, did I just discover the origin of the term 'dodgy'? )

 

[GAmes]

This might help.

http://www.cumminsforum.com/forum/94-98-engine/569868-fuel-shut-off-solenoid-fss.html

 

[BlameCandida]

So I should be able to test just the solenoid voltage by pulling the starter relay and putting a jumper wire across pins 30-87 (for just a few seconds, with the truck out of gear). That way there is no question of the starter relay not closing completely. Also, I think I've read that before '98 the fuel shutdown relay was in the PDC with the rest of the relays -- was there any special reason it got moved against the firewall?

 

[GAmes]

So I should be able to test just the solenoid voltage by pulling the starter relay and putting a jumper wire across pins 30-87 (for just a few seconds, with the truck out of gear). That way there is no question of the starter relay not closing completely. Also, I think I've read that before '98 the fuel shutdown relay was in the PDC with the rest of the relays -- was there any special reason it got moved against the firewall?

I suggest you just swap the starter relay with another that is in the PDC. Stray electricity can kill a PCM quickly. Also, the FSS is on the firewall 94-97 also.