weird idling problem...need help !!!

[jeffbboyz]

Dear ZTH members....

im driving a putra...previously there is no prob with this engine....just usual prob of the stepper motor with bad bad idling....

suddenly there is engine check light out...when i plug in diagnostic tools...my air flow sensor and also TPS faulty....after change these 2 sensors....and also a used stepper motor....everything was ok at first....suddenly one weird problem came out...

occasionally the idling will suddenly go up to around 3000rpm and refuse to go back to normal idle....sometimes i rev til 6000rpm for about 15 mins only the idling will slowly go back to normal....and sometimes it wont go back to normal but go below 1000rpm....

even i try adjust my timing or idling screw on the throttle body...it still stays at 3000rpm at idling and refuse to go back to normal.....and when this happens...i have knocking (or pinging) between 1000rpm to 3000 rpm during driving everytime i change gear....

hope u can give some tech advice on how to solve this prob...many thanks in advance...

Cheers....

 

[GSR06]

...Idling sensor, throttle body, or even ECU...based on my experience la..

 

[jeffbboyz]

tps sensor changed..airflow sensor change..engine check light no more..but i havent try swap the ecu yet..i also suspected is tps or ecu...

 

[boyzone]

Is u replaced with same code number air flow sensor?
Btw, high possibility is related with TPS position.

 

[jeffbboyz]

i pretty sure if i put in a perdana air flow sensor...it wont effect that much until go up to 3000rpm...

 

[TitanRev]

Highly culprit is the TPS sensor. Since you replace it with a used one maybe the TPS get stuck causing the high rpm...try servicing the stepper motor and see...I've service mine and idling went back nicely and until now there's no problem and idling is stable too.

 

[Paul_BGJ_4487]

Service throttle body 1st,
check the throttle body gear.

 

[GSR06]

Hey Bro, is your problem already solved?

tps sensor changed..airflow sensor change..engine check light no more..but i havent try swap the ecu yet..i also suspected is tps or ecu...

 

[jeffbboyz]

i check n service the throttle body n all the sensor before i install...still same prob...cant be solve...when plug in to the computer....tps sensor working fine n reading is ok...throttle cable ok...throttle body butterfly ok too...no sangkut....all have been done...but still same prob.....

 

[Paul_BGJ_4487]

i have same problem like you yesterday, but after services throttle body, problem has been solve, following address is the detail and part to change to solve for idle timing error, i found this on chinese car forum, Dont know true or not.

http://www.mudah.my/FICD+utk+masalah+Throttle+Body+tak+stabil-6486990.htm
http://www.mudah.my/Ficd+denso+toyota-6888080.htm

 

[jeffbboyz]

bro...mine is definitely not stepper motor prob...becoz when the car idling normal...it really works ok...idle at about 1000rpm...on air con then drop to 900rpm...engine smooth...stepper motor is working fine...just that when the rpm goes up...it will goes up slowly to 3000rpm n remain there...refuse to go back to normal unless if i rev the car for few mins....

throttle body all remove n even change to another one...service the throttle body n also sensors...when it is working fine...totally smooth...but once go up to 3000rpm...i pening gila...heheheh

 

[Paul_BGJ_4487]

better check fuel pedal + fuel cable too.

 

[boyzone]

check on the TPS voltage.

http://www.mitsubishiforum.com/forum/showthread.php?t=29830

 

[GSR06]

I had this problem also previously and I just changed the throttle body and the idling sensor. Do you have this problem without switching on the air condition?

 

[jeffbboyz]

throttle body...tps sensor and stepper motor is changed....problem stil the same even with or without air con switch on...if didnt switch on aircon...rpm stays at 3000...if switch on..will dropped to 2000rpm....

 

[GSR06]

Could you just test with a similar ECU to troubleshoot?

 

[oinkoink]

might be some where along the intake manifold is leaking.... try checking all the pipe connect to the manifold..

 

[jeffbboyz]

Could you just test with a similar ECU to troubleshoot?

ya...tats wat i wanna do next...might be the ecu....not too sure...will try to swap the 3rd throttle body n see how....

---------- Post added at 12:03 AM ---------- 6 hour anti-bump limit - Previous post was at 12:01 AM ----------

might be some where along the intake manifold is leaking.... try checking all the pipe connect to the manifold..

try check all the pipe connect to the manifold...at first i suspected was air leakage...but if there is a leak...rpm will goes up n wont go down..my problem is it will go down...drive like no problem...suddenly will goes up again...sometimes...it works fine for few days before same problem come back again....

 

[oinkoink]

when a manifold vacum leak the idle will go up and down... try seach in net for example of vacum leak. i am having the same problem now also.... suspect is manifold vacum leak..

 

[GSR06]

trying changing the throttle body as well as the idling sensor. For my case, I have changed >5x idling sensor as the mechanic got the 2nd hand ones. If there is an air leakage, you should feel the car will have no power at all but this is not the case right? If problem still persists after trying all the above, you should try to test on a used ECU to further confirm your doubt.

ya...tats wat i wanna do next...might be the ecu....not too sure...will try to swap the 3rd throttle body n see how....

---------- Post added at 12:03 AM ---------- 6 hour anti-bump limit - Previous post was at 12:01 AM ----------



try check all the pipe connect to the manifold...at first i suspected was air leakage...but if there is a leak...rpm will goes up n wont go down..my problem is it will go down...drive like no problem...suddenly will goes up again...sometimes...it works fine for few days before same problem come back again....