Bad idle after new ICV fitted.

[jrory86]

Hi!

Got my self in a bit of bother.

I have a avensis 1.8 vvti 16v Manual 2003 (53) and my idle was low and wobbling around 800 then 700, the cars check engine light came on and I took it to a garage and I was told the ICV was reading bad. I got it replaced and at 1st it was a high idle but now its kinda gone back to how it was. I reset the ECU by disconnecting the neg Battery lead and leaving it for 30 min and then reattach, turned key to ON position for 10 seconds and repeated that maybe 6 times. started car and drove. The car seemed fine at first and I was so chuffed but now and again when stopped the idle wobbles again between 800 an 700 (bouncing) the engine light has not come on....yet! Is that normal and the ECU is just learning again or does it seem I have a different problem? 

THANKS FOR ALL YOU HELP BEFORE YOU START. (",)

[FROSTYBALLS]

Hello Rory - welcome to Toyota Owners Club.

Post moved to the Avensis club.

[jrory86]

HI, I just realised I put it in wrong section Thanks frostyballs.

[gazza1286]

The ICV may have been part of the problem. Problems with that could have been caused by neglected maintenance of the air filter. This could have allowed contamination of the engine intake which may have clogged the idle bypass galleries. If this is the case I would suggest a couple of things:-

Did the garage also thoroughly clean the throttle body. (They really should have done this as part of the process) and;

Did the garage clean the MAF sensor? If clogged it may have also affected idling and responsiveness. 

Both jobs are relatively simple. Removal of the air cleaner box and rubber hose onto the throttle body using a 10mm socket is all you need. A good spray with carburettor cleaner and a rag.  There's a video on YouTube re the MAF sensor. 

 

An earlier model but the same principle:

 

 

 

The Maf video is for the Celica but is the same process:

 

[jrory86]

Hi Gazza1286, 

Yes im sure he said he cleaned it and searched for vacuum leak, he also replaced a breather tube. Can an old air filter be the problem? my car is just about due its year service so maybe that will help?

[gazza1286]

A new air filter won't solve an already clogged sensor or throttle body. It will only keep a clean air intake system cleaner for longer. (if that is the problem) 

[jrory86]

That makes sence, The ICV is new and the throttle body looks clean (no build up and the butterfly disk is clean) I took the MAF out and sprayed it with throttle body cleaner from Halfords ( when I was spraying it popped and crackled) let it dry and put it back in and no change to idle. I also started car and unplugged MAF and the car died so im guessing that the MAF is working.