[ripfish]

I do not understand the electical portion of the injection pump. I am referring to the cold idle solnoid, the cold advance, and I believe one more solenoid. When should they have voltage and when should they not?

I am having a hell of a time starting when cold. I am starting to move to the electrical portion of the fuel system as I have worked over the mechanical and fuel leaks along with the glow plugs.

How do you test the solenoids. Two spade connectors on top of the pump system. The one closest to the front of the truck has two wires going into the spade and has 12 volts with Key on. The one towards the back does not appear to have voltage with key on or cranking. However the engine is warm right now.

Interesting thing is this cold start problem seems to be getting worse, however starts right up when using block heater. It is 75 degrees outside. I am starting to think I am having solenoid issues??

 

[argve]

Ok here ya go...


Top rear terminal on injection pump = Timing Advance Solenoid - this will only have 12v applied to it when the engine is under 114° coolant temp. This is controlled by the temp switch that is located just behind the thermostat housing there on the passengers side of the engine.

Top Front terminal on injection pump = This is the Fuel Shut Off solenoid - Should have 12v applied here any time the key is in either the ON or START positions. When you shut the key off this solenoid looses power and shuts the fuel off which then starves the engine for fuel.

Passengers side of injection pump (bolted on side of injection pump) = Fast Idle Solenoid - this as 12v on it when the engine is below 114° coolant temp - this is also controlled by the temp switch behind the tstat housing just like the Timing Advance Solenoid.

Now both the Timing Advance and Fast Idle solenoids will only have power if the key is in either the ON or START position AND the coolant temp is BELOW 114°

Check these out for proper operation and get back with us even if you find something wrong and it gets you back running - reason for that is there are 20 other folks with the same hard start problem but they are too shy to post so you will be helping them. If by chance you find nothing wrong post back and we can give some more suggestions on things to look at but let's take it one step at a time. The checks above will take like 2 mins with a voltmeter - less time if you can con the wifey poo into sitting in the truck to flip the switch to see a change in states between position OFF and ON but not start - I say that because I have never seen a condition where it would work in ON and not START...

 

[ripfish]

Is it possible for the temp switch to fail so that those two solenoids do not get power? I need to make sure the truck cools down more to check, but I believe that I am not getting power to either of those two solenoids controlled by the temp switch. Using a jumper wire, I know that all three solenoids are functioning when they do get power.

Thanks for the great explanation of those items! Stay tuned...

 

[tim94f250]

[ QUOTE ]
Is it possible for the temp switch to fail so that those two solenoids do not get power? I need to make sure the truck cools down more to check, but I believe that I am not getting power to either of those two solenoids controlled by the temp switch. Using a jumper wire, I know that all three solenoids are functioning when they do get power.

Thanks for the great explanation of those items! Stay tuned...

[/ QUOTE ]

Yes. The timing advance and the cold idle solenoids get their power through the engine temp switch. When the engine is cold, there should be power on both sides of the engine temp. switch. At 144 degrees, the switch opens and cuts power to the solenoids. It is possible for the switch to fail open so the solenoids never see power. The wire that carries the power to the two solenoids from the engine temp. switch is gray/red stripe. Tim

 

[ripfish]

That's it!! No power to either of those cold starting assisting solenoids. My water temp is cold. Guess what? The daily driver also just told me the the temp gauge has not been working in the truck.

Now the question is what next?

There seems to be three different temp sensors on this thing. One behind the Radiator hose on the passenger side of the solenoids with a two spade connector.

There are also appears to be two seperate water sensors on the drivers side of the motor towards the front of the motor. One is above the other about 6"?

 

[BuilderBob]

[ QUOTE ]
No power to either of those cold starting assisting solenoids.

[/ QUOTE ]

Those solenoids have not worked in my truck since the mid 1990's, and my truck successfully starts in cold temperatures that you may not be able to comprehend, -28degF.

Good Luck

 

[tim94f250]

Follow the red/light green wire from the FSS to the engine temp switch. There are two red/lg wires on the FSS. One goes to the glow plug relay, the other to the engine temp switch, that I think is behind the thermostat housing. Tim

 

[ripfish]

Bob I am afraid you are right. A local mechanic said those solenoids not being energized, really should not keep this thing from firing. I am going to jumper them to the hot fss solenoid just to be sure in the morning and see how it starts.

He still thinks it is air

If this is not it, I do not know where to turn. I have clear lines before the filter, between the filter and #1 return, and between the injection pump return and the back return line point.

Before I did the return line kit, fuel was draining back and the line before the filter would be empty by morning.

Now I have fuel in all the lines and this thing seems harder starting than it ever did before return kit was done. What the f$#@!!

 

[OkieGringo]

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