INJECTOR PUMP WIRES

[MIDNIGHT RIDER]

1985 F-350 6.9 engine.

On the driver side of the injection pump is two terminals.

The terminal closest to the radiator has two wires both connected to the one terminal. Where do they come from and what function do they perform??

It appears that both these wires go into some kind of sender screwed into the top of the engine at the passenger front; but, I am not sure.

The terminal closest to the firewall has one wire. Is this the run/kill wire??

When I try to find these wires in the harness, the colors don't add up.

 

[The Warden]

Without going out and actually looking, I believe the plug with the single wire is the fuel shut-off, and the other one is the cold timing advance solenoid.

It's been a while since I looked at my harness, but I believe there's a single wire coming up the harness for all of these. This wire is energized in "RUN" and "START", and splits off by the injector pump. One of the wires goes to the fuel shut-off, and the other goes first to the sending unit (which has two plugs and cuts off the electrical connection when the coolant temp's about 120 degrees), then to the cold timing advance solenoid (near the fuel shut-off) and then to the cold idle solenoid in series.

Hope this helps

 

[OkieGringo]

I'm not sure if the newer 7.3s up to 94 are the same as the 6.9s, but this is how the wires should hook up.

To check the connections to the IP, here's what you need to do. Turn on key to 'run' position. Check the main wire that comes from the loom to the IP (injection pump), does it have juice. The wire runs to the FSS (fuel shutoff switch) connector first, then to one side of the Cold Engine Switch(two-prong sensor, located in hole behind the upper radiator hose connection). When the engine is cold 'juice' will pass thru the sensor, if the sensor is good, and go to either the FIS (fast idle solenoid) or the CTA (cold timing advance), then to the other. If the engine is cold and sensor is good it will be 'closed' and allow 'juice' to get to the FIS plunger which holds the idle speed up. If FIS plunger is working, but not pushing up far enough, use a 1/4" wrench to turn/extend it until the idle speed is ~1000 rpm. The CTA (cold timing advance) near the spider/distribution end of the IP 'advances the timing' to make engine run smoother/run cleaner/less smoke. The Cold Engine Switch opens/shuts off the electricity to the FIS and CTA after engine reaches 112 degrees, and engine speed/rpm will/should drop to ~650 rpm. If these three items are working correctly, when you go to start engine, hold the throttle pedal at least 1/2 way to floor to allow the FIS plunger to 'set' itself. Use a test light to check for electricity/juice at each of the solenoids, FSS, FIS and CTA. Let me know if this helps. Good luck, OkieGringo