High Idle

[adamstanford]

Now if it was a 2zz then id be all over this but ive no idea what that is. Is that the "waxstat"? That ive read about? Does it have any detrimental effect on the running of the car? Or can i just leave it as is

[jimi]

Is that the "waxstat"? That ive read about? Does it have any detrimental effect on the running of the car? Or can i just leave it as is

Yes, the waxstat controls the AAV (Auxiliary Air Valve) Basically it's an air valve that is controlled by coolant temperature. When the engine is cold it's open and allows air past the throttle butterfly, the MAP sensor tells the ECU about the drop in manifold pressure (more air) and the ECU alters the fuelling to suit causing the rpm to increase, which is why the MK1 can idle at 2/2.5k rpm when cold. As the coolant heats up the valve closes, reducing the air, ECU compensates, idle drops. The warm idle is set by an air screw on the top of the throttle body (normally hidden under a round black plastic plug)
They are well known for sticking and causing problems.
Detrimental effects ? It can make it extremely difficult to get the car to idle properly and increased fuel consumption are the obvious ones.
There's an easy check to carry out to find out if the AAV is functioning properly.
With the engine at normal running temperature, take the inlet pipe off the throttle body, if you look at about the 5 o'clock position you will see a small hole (about 5mm dia ) block off the hole with your finger (press tightly) and see what happens
The hole you want to block is marked C in this picture.

More info on the AAV and solutions here
http://www.mr2oc.co.uk/know-your-2-know ... kbartid=54
http://www.mr2oc.co.uk/know-your-2-know ... kbartid=55
http://www.mr2oc.co.uk/know-your-2-know ... kbartid=56

[jimi]

Split from this thread http://www.mr2oc.co.uk/forums/40/163224.html
Don't want to hijack the OP's thread

[adamstanford]

Thanks jimi ill check this out later in the week once im home from the lake district. The cars took a bit of a pounding so itll need a good going over once its back.
On another note i wish to remove the induction kit thats literally attatched straight to the tvis manifold, what size ID silicon pipe will i need to fit the manifold? Id like to reposition the airfilter slightly further away from the manifold. Thanks again!

[jimi]

Throttle body spigot is 65mm O.D. with 1or 2mm retaining lip. So you'll be looking for something with an I.D. of around 66mm although a 65mm I.D. silicon hose will probably stretch enough to be a tight fit.

[adamstanford]

Thats great thanks i know what im looking for now. Is it you that makes the throttle body contraption? That moves the big spider frame thing away?

Thanks

[jimi]

That would be me CLICKY

[adamstanford]

Nice little read. They look very tidy, can i take one at the end of the month please? Just with a basic as-is finish? If youre still making them of course.

[jimi]

PM me when you want one

[adamstanford]

Of course sir. Thank you!

[Picaro]

I don't have the link handy, but fyi: MR2oc.com (US) has a very new thread in the general MKI section that shows exactly how one can take apart, adjust, and reassemble the aux air valve if it is not performing properly. The guy who did it included lots of very good pics and proper detail of what he was doing. It's one of the best 'how to's' I've read in quite awhile.

There is a circular plate inside the valve that is set at the factory to the proper distance from the wax stat, so that as the wax stat heats up it closes against this plate, shutting off the extra air. As the rubber encased wax stat ages it probably dries up and will no longer seal against that plate properly. By placing the disassembled valve in a set temperature pot of water one can view how far the wax stat expands and then adjust the plate so that it will now seal properly when warmed up. I'm usually not overly keen to tear stuff like that apart, but this looked a bit more simple than expected, so even I would probably try it if needed.

Also, if closing your idle speed adjustment screw does not cause the engine to at least stutter, when warmed up, that is usually a definite sign that you have an aux air valve problem.

[jimi]

That's a good write up
http://www.mr2.com/forums/threads/10453 ... adjustment
Obviously it will go again and eventually there will be no adjustment left as the wax capsule fails totally.
Personally I'll stick with Paul's solution (as per the links in my post above) I did it on my car 10 years ago and have never had the slightest problem with the idle since. It's easily paid for itself in fuel savings

[Picaro]

I understand your thinking, especially if the choke works that well. Great job on the timer by the way. And my apologies for quoting the wrong forum.

[adamstanford]

I have another query. My oil pressure gauge on the dashboard reads about 1/4 on idle and about 2/3 when its on the go.
Its full of oil (petronas 5w40 full syn), and runs ok. No knocking etc.

Is this normal? Or should i be worried