Engine Idle Speed

[Edward]

I did a engine tune up very recently, after the tuning I notice the engine idle speed is not constent. It goes up & comes down. What may be the reason. The car is toyota 110

Edward

[Uditha88]

  Edward said:

I did a engine tune up very recently, after the tuning I notice the engine idle speed is not constent. It goes up & comes down. What may be the reason. The car is toyota 110

Edward

Hi,

After a Tune-Up I noticed slight increase of idle RPM. But it doesn't go up-down. Better if u can bring it back to the place n get inspected.

Re checking Injectors n Throttle Body.

[Ripper]

  Edward said:

I did a engine tune up very recently, after the tuning I notice the engine idle speed is not constent. It goes up & comes down. What may be the reason. The car is toyota 110

Edward

do you notice this with AC on and off? or is it the same irrespective of the AC?

If that's the case...i would guess during the tune up...something would have messed up your TPS...throttle position sensor!

or the IAC....idle air control valve.

I'm leaning more towards the IAC...

doubt it's the injectors... best to take her back to the tune up joint and ask them to sort it out for you

being armed with some knowledge always helps so those people don't BS you around...

[weda]

  Ripper said:

If that's the case...i would guess during the tune up...something would have messed up your TPS...throttle position sensor!

or the IAC....idle air control valve.

I'm leaning more towards the IAC...

My 110 sprinter with 5A-FE (1500cc) had a simillar case.

Symptoms were simmilar to a petrol block, idle speed not catching up, auto governing and no start in ad-hoc time.

Got it scanned by a fellow in Moratuwa-> Defect shown in IAC and was recommended to replace.

Had a IAC swap but the problem re imerged.

My general mechanic suggested to clean up the throttle body thinking that the choke was struck with carbon, and it was.

Further inspections revealed a damaged vacumme hose to a senson-> replaced it.

During tune up the current was irregular, so the delco was sent to a delco specialist at Maharagama. He wanted to check the control box and all the symptoms he predicted were there in the car. So I gave him to check the control box where it had a malfunctioning IC. I had the option of repairing it or replacing the box, Preffered to repair.

Hope that the problem is OK now, will check and let you all know.

[weda]

  weda said:

Hope that the problem is OK now, will check and let you all know.

Even after the ECU treatment there was a slight problem and the fuel filter was replaced. No more check engine!

The idle speed is extra smooth and during the last 800 Kms the performance was above expected level.

If i had gone replacing the sensors as instructed donno where it will end up. Credit goes to my mechanic who went by the theoritical andlogical analysis.