Urgent High Idle! I Need Help Figuring This Out, Please.

March 12, 2011

Hi there...

I have a problem with my car idling at 2,000rpm when it's warm

Problem started when I installed the wiring for my LPG.... ran the car, set it all up in the software and went to mount to LPG ECU behind the throttle body... In doing so I managed to snap the throttle position sensor in two... So I purchased another entire throttle body assembly from a scrapped 1998 Avensis 2.0 mine is a 1999 with 3S-FE By the way... and bolt that on.... Uh-Oh same problem... I was thinking this TPS could be dodgy... but the multimeter shows a smooth transition in omhs...

I've purchased another complete throttle body incase this one is duff... but if I have the same problem when I fit this, I don't know where to look...

I've ruled out any sort of vaccum leaks... and any air in the coolant system...

If I unplug the idle control valve, I get a check engine light and the idle drops to an acceptable 1,000rpm.

If I unplug the TPS I get no check engine light and no change in idle... I have noticed since fitting this throttle body, it is difficult to smoothly change gears, then the engine is in overrun (engine braking) it seems very jerky between this and then accelerating again, Prehaps as the Idle control valve isn't working as it should... if I pump the brakes, I can get the car to hunt between 1,500-2,300rpm.

I've tried cleaning out the valve and maybe have put it back together wrong... There's obviously the electromagnetic element which the weatherproof plug goes into, but at the other end there is a coiled piece of metal, which sits in a cut out on a piece of plastic and limits the movement of the metal fin controlling the bypass air flow... There only seems to be two ways of putting them in... one leaves the idle valve wide open, the other leaves it prehaps 3/4 closed....

Maybe a guide to how to assemble the Idle control valve would be a place to start, otherwise suggestions?

I really need to get this fixed ASAP.

March 13, 2011

Just an update.

I've seperated the Idle Control Valve from the Throttle Body....

But this time, I've assembled it without the coiled piece of metal, which expands when it heats up on...

Success, the car idles at the correct speed!

What does this actually do? I'm aware that when it heats up the metal expands much like a thermostat in principle and is supposed to close off the idle valve a little more to bring the idle down...

However the car seems to start high 1200rpm, warm up and end up at the correct idle speed anyway around 850rpm.

If I put this metal coil in no matter which way, it seems to jam the valve full open or partially closed, I've fitted it every concievable way...

I'm still waiting for the new throttle body, but for the time being, I've removed this piece of coiled metal with good effects from the metal plate and just screwed it back together...

Can any damage occur?

The TPS and Idle accuator are now plugged in, the car drives perfect no jerky gear changes or when coasting... No Check engine light all seems well =)