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Pete, Car Enthusiast
Category: UK Car
Satisfied Customers: 25764
Experience:  Over 17 years experience diagnosing and repairing automobiles.
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I have got an engine problem with my Mitsubishi Pajero Io,

Customer Question

Hi, I have got an engine problem with my Mitsubishi Pajero Io, 2001, engine GDI 2.0L (4G94).
I bought this car 5 months ago approx. It has 110kms.
The symptoms are:
- low and rough idle with engine warm and when the car is stopped. Idle is most of the time around 200-300rpm, and unstable. However it has never stalled. When engine is cold (first minute of drive), idle is perfect, i.e around 600rpm. This symptom got worse after a one month summer break where I disconnected the battery. For the first drive after this break, I forgot to follow the idle relearning function, but since them, I disconnected the battery again and followed the procedure, but with no change in the rough and low idle.
- The feeling of "impact" when decelerating. While driving, when I fully release the accelerator pedal, a sort of clicking noise can be heard distinctly.
Apart from these symptoms the car was driving well since recently (smooth acceleration, no hesitation)
Submitted: 1 year ago.
Category: UK Car
Customer: replied 1 year ago.
I did the following
- cleaned the throttle body with appropriate cleaner: no change
- cleaned the PCV valve: no change
- inspected visually the mass air flow sensor, which looks clean (so I did not clean it)
- tried to adjust the throttle position sensor by "ear" (I have no voltmeter). After this last adjustment, and while driving the car on a freeway and having a hard acceleration, the engine check light started flashing, and I immediatly lost almost all of the power ("limp mode"). I disconnected the battery and the engin light went away and the car could be driven normally again, but since then the engine light and "limp mode" have been reappearing from time to time. I put the TPS back in its original position, but my symptoms are still the same (low/rough idle, feeling of impact when decelerating, engine light and limp mode occasionally)I am looking for someone with a MUT II tool, but in the meantime, I would like to undergo all the checks I could do myself. As from the symptoms I described (low and rough idle only when engine is warm, feeling of impact/noise when decelerating) and what is in the Mitsubishi workshop manual, I guess than the air inflow is too low at some points, and that the electronic-controlled throttle valve system may be the cause. Thus the next steps I am planning are to buy a multimeter and to check the resistance of the TPS, the accelerator pedal sensor, the throttle valve control servo motor.
Any suggestions on this?
Many thanks
Customer: replied 1 year ago.
I just bought a digital multimeter. Here are the results of the tests I have been able to perform since then:ACCELERATOR PEDAL SENSOR:
resistance 1st channel : 4.9kohm --> OK (standard value 3.5 - 6.5 kohm)
resistance 2nd channel : 4.9kohm --> OK (standard value 3.5 - 6.5 kohm)
Continuity between connector 4 and 5 : when pedal released no continuity (165ohm resistance). Workshop manual says it should be continuity (0ohm) --> OK?THROTTLE POSITION SENSOR:
resistance between terminal 1 and 3 : 2.4kohm --> Not good? (standard value 3.5 - 6.5 kohm)THROTTLE VALVE CONTROL SERVO:
Operation check is ok: the throttle valve actually opens or closes in response to the accelerator pedal depression
resistance between terminal 1-3 : 2.6ohm --> OK? (standard value 1.35 - 1.65 at 20°c. The actual temperature when testing was above 20°c, maybe 40-45°c)
terminal 2-4 : 2.2ohm -- > OK? (standard value 1.35 - 1.65 at 20°c. The actual temperature when testing was above 20°c, maybe 40-45°c)
no continuity between the terminals and the body --> OKPURGE CONTROL SOLENOID VALVE
Resistance between terminals : 34ohm --> OK (bit too low but i guess ok: standard value 36 -44 ohm)
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

If you haven't checked or cleaned the intake free of carbon this can cause this here.I have seen on some models where carbon build up will cause this fault here in the intake and needs cleaned.If this was already checked or cleaned or was not found at fault here let me know.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.