Adjust High Idle?

[thirdstreettito]

Well, I see on the end of the rod in the high idle solenoid(on the top/side of the IP there is a slot for a flathead screwdriver. Im guessing its the adjustment screw. When I cold started my truck this morning(because cold start=high idle)I turned it right and it barley moved, so I turned it left and it moved and the idle went up maybe 50-100RPM. How far can I turn it? Also, how do I hookup a high idle switch? So I dont have to get a stick for the pedal. Thanks in advanced.

[NH2112]

If your engine is cold and you give 1/2 throttle or so while cranking, the fast idle solenoid should energize and hold the throttle lever down for about 800rpm. If it's not energizing test for power at either of the green wires (one is fast idle, the other is cold timing advance aka Housing Pressure Cold Advance) and work your way back to the temp switch at the rear of the passenger side head.

If your current fast idle/HPCA circuit isn't working and you don't mind not having it work automatically, installing a manual control is no more complicated than running a wire from an ignition-hot source to a switch (with inline fuse for safety) and from there to the fast idle & HPCA solenoids. You can tie right into the factory harness by connecting the switched power wire to the green wire after disconnecting it at the temp switch. If you want the automatic system to work and to have the manual switch you obviously won't disconnect the wires from the temp switch, and you'll want to install diodes in each circuit to prevent the energized one from backfeeding the de-energized one and potentially causing crazy random electrical issues. Just tie both systems together at the fast idle solenoid, remove the brown terminal and crimp both wires together into an insulated female push-on terminal - a 10-12 gauge (yellow) one should fit right.

Here's a schematic I drew up that assumes you want the automatic system working as well as the manual system. I have it set up so that you only get fast idle and no HPCA using the manual system - if you want both to operate on manual, put diode 2 between the HPCA solenoid and the temp switch. The bars on both diodes go toward the injector pump in that case.

http://i230.photobucket.com/albums/ee245/NH2112/Dieselschematic-1.jpg