Hot afternoon idle problem

[Veloc]

Hi all forumers and sifus...

Hope you all can advise me and give some input. On a particularly hot afternoon, when aircon is on, my car's idle is unstable. If I press the gas and release, it will drop extremely low ~400 rpms. Sometimes it bounces back but sometimes just stays there. And I hate it because at that low speed, the engine vibrates.

Last time my other old car also got same prob. Even worse. It bounces up and down and sometimes die off...

Can please advise what problem is this?

Thank you...

 

[feipepe]

hi bro,
what model car r u using? can u describe more detail a bit?

 

[Veloc]

Toyota Corolla AE111, 4A-FE. Any opinions?

 

[jamesweh]

Possible some fuel mixture problem as in the hot afternoon, air density is at the lowest. So running too rich. Can you adjust your fuel mixture at idling?

 

[DanzEterna]

have u serviced your throttle body lately?

 

[levin818]

Hi Veloc, try look into the following:
1) throttle body - stiky/dirty/clog TB will restric air flow and cause idling issue
2) ECU - I have rebuilt few unit of 4A-FE AE111 ECU so its possiblie that yours having problem

 

[Veloc]

Possible some fuel mixture problem as in the hot afternoon, air density is at the lowest. So running too rich. Can you adjust your fuel mixture at idling?

have u serviced your throttle body lately?

Hi Veloc, try look into the following:
1) throttle body - stiky/dirty/clog TB will restric air flow and cause idling issue
2) ECU - I have rebuilt few unit of 4A-FE AE111 ECU so its possiblie that yours having problem

Thank you guys...

Bro Jameswah, I don't think it is air-fuel. I will look into it after checking my TB. Thanks man.

Bro Danz & Levin818, I also suspect it's TB dirty. But I felt funny why in a hot afternoon it gets so severe. If it's TB, then should be everytime.
My previous car, Daihatsu Ascend, was so bad that the engine would die. This happens at night as well. But my curent car, mostly on hot days...

 

[cosmicgate]

Please check that both your radiator fan and condenser fan is spinning when aircond on.

 

[D7zul]

check ur radiator coolant also..

 

[kaderAE101]

U can try removing the throttle body & clean it with Petrol or Throttle body cleaner..
After cleaning... Car will have smoother, stable Idling

If cleanig doesn't help, may have to replace a recon throttle body !