QuestionI don't know if you can help me. I am employed in Saudi Arabia and drive a 1999 Hyundai Galloper Exceed II. With a 3.0l Fuel injected engine (same as installed to the Early Mitsubushi Pajero).
For some months now my engine check light has been comming on intermittently. I have changed several components ie coil, HT Leads, HT Cap rotor arm and inlet sensor with no effect. However the idle speed has been fluctuating between 200 and 1300 rpm, sometimes actually cutting out with difficulty restarting. I replaced the fuel filter and cap with no change. the check light is not always on when the idle is erratic. My local dealer will not look at it unless the check light is on permanently. Could it be the Idle Solenoid and how do you check it out ? Any help would be appreciated.
Many thanks
Geoff R
AnswerHi, Geoff. I'm not familiar with this vehicle, but have worked on many Mitsubishi 3.0 systems, so I'll try to give you as much information as I can.
A fluctuating idle like you describe (with no misfire) is usually caused by something incorrect in the idle control system. Typically, it occurs because the idle is too high, the idle actuator cannot compensate, and the ECM (engine control module) turns injectors on and off in an attempt to idle the engine properly.
The first thing to do would be to check to make sure you have slack in the throttle cable.
Next, check the idle switch. This will typically be a separate switch in the throttle body or, if you have a 4 wire throttle position sensor (TPS), a switch in the TPS itself, which is closed at idle and open when throttle is applied. If it's not working properly, you'll need to adjust the switch (or TPS) or replace as necessary. On some cars, there's an electrical connector that needs to be grounded (labeled something like ETS adjust).
Third, you'll need to check and adjust the base idle if out of specification. The same electrical terminal will need to be grounded. Then you can adjust the bypass passage (a screw on the top of the throttle body) or the mechanical mechanism that controls the idle.
Fourth, you'll need to check the idle actuator itself. Unfortunately, because I don't know what kind of idle actuator you have, I cannot give you information on how to check it.
But the situation with the dealer really has me puzzled. Are they basically saying the fluctuating idle is normal unless the check engine lamp is on?? I'm at a loss as to why they cannot diagnose the idle separately from the check engine lamp being on. In any event, I hope I've helped at least a little.
