How do I check Idle Air Control?

[rungrote_c]

I found problem about Idle speed not smoothly. I 'd check IAC valve but don't know how to check. If any know, please reply.


rote

 

[LilKeV84]

not so sure oso

maybe u can see if the valve can move nicely or not? but what u mean by idle not smooth? rpm drop and rise without doing anything?

 

[jaywat]

Many problem can contribute the above problem one wor...vacuum leak, fluctuated electric current and bla bla bla

 

[rungrote_c]

not so sure oso

maybe u can see if the valve can move nicely or not? but what u mean by idle not smooth? rpm drop and rise without doing anything?

Yes, RPM drop around 500 rpm which normal around 800 rpm. It will found some timimg. Do you know what's problem I found?

 

[Supachip]

check the idle gears set (plastic one) one the thottle housing. The gears might need lubrication (put more grease)

In the worst case, the gears might be broken. Can get for around RM45 per set.

 

[darkbob]

hmm...

what car r u driving bro ?

 

[trex92]

check the idle gears set (plastic one) one the thottle housing. The gears might need lubrication (put more grease)

In the worst case, the gears might be broken. Can get for around RM45 per set.

Supachip, i wanna ask which proton model got this plastic gear? Coz the other time I took apart my Throttle body but could not find any plastic gear. I found an idle speed motor. I am driving a Putra. Some people told me i need to open the screws located at the bottom of the TB in order to access these plastic gears, but then i used something to poke thru the hole at the Idle Speed Motor, I noticed, the hole goes all the way through with nothing obstructing (meaning no plastic gear inside). Also, the screws I mentioned, I tried to open but could not, and in the process, totally wore out the screws... :(

As to rungrote, try to service your TB. It helps a lot for stable idle.

Currently my symptom for my car is like this, idle is stable. But when rolling I throttle off to let the car roll, I feel my engine is dragging my car slower until to a point close to 1krpm, I would feel a jerk and then my car would roll smoother. Sometimes also when from a stationary position to a moving, under slight throttle and slow acceleration, I would also feel some sort of a drag, when reach slightly higher RPM around 2-3krpm, I would feel a jerk and my car would accelerate better without a drag. Kinda makes me suspect that the idle speed motor is not opening fully when it should... advice anyone?

 

[darkbob]

Supachip, i wanna ask which proton model got this plastic gear? Coz the other time I took apart my Throttle body but could not find any plastic gear. I found an idle speed motor. I am driving a Putra. Some people told me i need to open the screws located at the bottom of the TB in order to access these plastic gears, but then i used something to poke thru the hole at the Idle Speed Motor, I noticed, the hole goes all the way through with nothing obstructing (meaning no plastic gear inside). Also, the screws I mentioned, I tried to open but could not, and in the process, totally wore out the screws... :(

As to rungrote, try to service your TB. It helps a lot for stable idle.

Currently my symptom for my car is like this, idle is stable. But when rolling I throttle off to let the car roll, I feel my engine is dragging my car slower until to a point close to 1krpm, I would feel a jerk and then my car would roll smoother. Sometimes also when from a stationary position to a moving, under slight throttle and slow acceleration, I would also feel some sort of a drag, when reach slightly higher RPM around 2-3krpm, I would feel a jerk and my car would accelerate better without a drag. Kinda makes me suspect that the idle speed motor is not opening fully when it should... advice anyone?

Just MY 2 Cents..

maybe the screw u tried to open, needed a few impacts ?

this is just my opinion.. not sure...

 

[trex92]

Just MY 2 Cents..

maybe the screw u tried to open, needed a few impacts ?

this is just my opinion.. not sure...

yup, good suggestion, I also tried that by taking a hammer and hitting the screws a few times before trying to open it. The thing is they used screws instead of bolts, so opening is really really hard (the head of the screw is round so cannot use spanner) and also I am suspecting because they used screws, maybe that part of the TB is not meant to be opened up anyway, so no need servicing there wan.

 

[Supachip]

Trex92, The plastic gears is located right under the TB facing the air filter. 2 philip screws are there to hold the cover.

I think u better find a ceaser and knock open the screw, they maybe jammed.

Be very careful with the gears, there are many small parts.

check for cracked / chipped teeth. Else just put more grease on all the gear threads.
The original grease in there tends to dry up by engine heat after some time.

 

[trex92]

Trex92, The plastic gears is located right under the TB facing the air filter. 2 philip screws are there to hold the cover.

but there is where my Idle Speed motor is located. Not really below the TB but its below the air intake pipe to by TB. Held by 2 bolts but with phillips holes. The Idle Speed Motor got no gears. It works on a extend/shorten method and the hole which it covers got no gears inside. The part is seen in this website http://www.stealth316.com/2-isc-iac.htm and I have already done as mentioned in the website...

 

[rungrote_c]

hmm...

what car r u driving bro ?

My car is Civic Vti 1999, 1600CC. I don't know tpye of IAC of my car. After I read the member post, it's look like the tpye of IAC is servo control. Do any have method of clean and check for my civic.

Rote

 

[trex92]

civic? hmmm... dunno much about it, if proton then can help with directions.

 

[huakenny]

if u see ur throttle body..there r basically two sensor..one is attached to the butterfly there....and another one is ISC.....but civic hv to see la....dunno....

 

[purple_EJ7]

Hi, though this is a very old thread but I find the is very interesting so I think I'll just share some of my experience on my friend's wira. Most proton will have the stepper motor IAC which consist of 2 coils & 1 ballscrew. The coils are the ones that usually becomes faulty. How to know? Take a good IAC and measure the resistance (in ohm) between terminals of each coil. Compare it with yours, it should be the same. I didn't remember the values but we took a halfcut IAC, which happens to have 1 faulty coil, swapped it with a good coil from the existing IAC (which also have 1 of the coils faulty, main reason of getting a new IAC) and we were good to go. For Honda Civic, well, mine is using duty control ACV (my car is auto, so it maybe different for manual). Not sure how to check but I believe a computer diagnostic should be able to capture the faulty ACV. TPS (the that sticks to the TB butterfly) can also be checked using multimeter. Take off a good TB, measure the initial resistance of the TPS. This value should be the same for all TB of the same model. When you open the butterfly, resistance value should change. if not, then yours is faulty. WARNING!! do not adjust the TPS if you do not know what you are doing. A slight movement of the TPS will make your idle change drastically, believe me. If you really want to adjust it, make sure you find your own skill or method on how to lock the TPS screw without moving it during tightening. Good luck on that because the last time my friend tried to adjust it, it took us more than an hour.

 

[nimosy]

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