Chrysler Repair: Idle Control, dodge avenger, chrysler engines

Question
Thanks for the advice about purging idle, it did help me find the likely problem.  But I have a question about vaccum lines. Most of the vaccum lines will be basiclly be on top of the motor? Like the ones that run off throttle body and valve cover for the air intake? What other vaccum line should i be looking for?(general location) Also I checked wiring running from ICM down to other wiring and came across most of the wires were oily and wet, at the lowest point in the wires there was oil/water sitting. I have not done anything but drain that out. Should I replace new wiring covering that cover all the wires, and spray wires with wire dryer and clean,inspect for melted or bare wires? If so, any tips on removing old wire covering? Should I disconnect battery? And if I do find wires melted togther could I simply twist and use crimp connecters and electrical tape? Does it matter how wiring is layered? And if I do all this and still have the same problem what other factors could play a role? Could it be possible that mechanic did not set timing correctly? What about exhaust system? Thanks for your time and I will let you know after the wiring inspection.

         Tony

Followup To
Question -
I have a 95 Mitsubishi Eclipse 420A non turbo DOHC 5 spd 2.0L I know that this engine is similar to the dodge avenger and chrysler engines. My question is this, my idle had been pruging high every now and then up in the 1500-2200 range. Check engine light codes read 25(idle control motor) and of course 55(end of codes) but, I recently replaced the idle motor and still have the same problem. Also I recently had a head job done and they set the idle to the faulty ICM. No missing just idle purging. Do I have to set idle to new motor speed? I was told that if I have a Vaccum leak also I would experience this problem, is this true? Recenlty blew a water hose and may have got air in the cooling system while replacing hose and simply filling back up...,   later i drained all fluids from the radiator but not the block. If air is still in the cooling system would that also cause idle purging? What other factors do you think play a role in this Idle problem? All codes read 25 and 55.Thanks for you time
Answer -
Hi Tony,
Yes, a vacuum leak can cause the idle speed to rise via feedback from the O2 sensor which sees a too lean mixture and causes the controller to lengthen the injector pulse. That will of course raise the idle, just as if you opened the idle valve. So look for that kind of issue first. The cooling system is totally unrelated to the manifold vacuum question, so forget that possibility.
The other possibility, now that you know you have a good icm is that the wiring between the controller and the icm has been shorted in some manner (which is one of the reasons that the code 25 can be set). I would suggest that you look carefully at the wiring of the icm as far as you can trace it to make sure that the insulation of the wires hasn't been melted by the nearby heat of the exhaust manifold for example. You may need to cut apart the four wires where a melt-through has occured and reinsulate them from oneanother. The four wires are divided in pairs, each pair drives the motor in one direction so between them they open and close the air passageway. On the 2.0 Chrysler engines there is a 4 prong plug arranged linearly, with the outside 2 controlling one motor coil and the inside 2 the other coil. They are attached to pins 48-58 and 49-57 of the engine controller, but I can't be sure the assignments are the same for the Mitsubishi controller plug. You would want to verify that the wires are not shorted to one another when you have pulled the plugs at both ends of the cable (the 4 way and the 60 way) and that there is a unique connection for each of the wires at both ends. If that checks out, and you have a new motor, then the remaining possibility is the controller is bad but that is very unlikely. I think you will either find a vacuum leak or an electrical short or open circuit that can be repaired. Let me know if this helps you.
Roland  

Answer
The most complete picture of the vacuum lines is the one shown on the underhood EPA label. That is typically a very complete drawing. The vacuum source is of course the intake manifold. So look at everything that is attached to the manifold and trace all the branching lines therefrom. On the wiring, I would be very reluctant to cut into any wires unless they were hopelessly melted together. If at all possible avoid having to splice because each such repair is a site for potential corrosion and breadown. Try to preserve as much of the original wiring as practical, and use some two-part epoxy to patch over any insulation that has exposed bare wires. So I would clean and dry to the point where you can get a valid assessment of the condition of the wire harness but be content to leave well enough alone. Also pay some attention to routing the wires so that they don't unnecessarily contact hot surfaces of the engine (the head/block/exhaust manifold), but the layering between wires in not so important as in TV wiring for example. If the harness wrapings are degraded you can get some helical covering that is heat resistant to wrap around the wire harnesses. While the timing is a relevant question, it may even be the case that the timing is not adjustable (if the engine does not have a distributor in the classic sense of the word) but rather uses sensors for obtaining the position of the crankshaft and camshaft and then sets the timing automatically based on that. The exhaust system usually shouldn't be associated with idle problems except if the engine will not idle at all which can be the result of a stuck open exhaust gas recirculation valve.
Roland