Thread: Hi Idle

Not sure I've noticed any difference in idle speed between trumpet off and on, unless its been on LPG and you're altering the mixture thereby. You can of course cut off the flare off the trumpet and install that straight into the lid, a bit of silicone and pop rivetting should do it.

Originally Posted by bee utey

Not sure I've noticed any difference in idle speed between trumpet off and on, unless its been on LPG and you're altering the mixture thereby. You can of course cut off the flare off the trumpet and install that straight into the lid, a bit of silicone and pop rivetting should do it.

The LPG bit did occur to me, so I flicked it over to petrol and found the same thing I guess it's possible the idle stepper motor has happened to die at the same time as I've been mucking around. The thing is though .......... The idle plummets back to normal levels with just a small portion of the intake covered.

Weird right? I bet the idle circuit needs a slight intake restriction to work.

I fitted a new air cleaner at the same time .... I guess I should try re-fitting old one and see if it's restricted enough to allow it to idle

BTW: That an absolutely HUGE intake restriction. I wonder what the reason for it is. It sure does seem to go better without it.

seeya,
Shane L.

If there's a significant air leak downstream of the MAF a tiny change in restriction would affect the air flow reading to the ECU, changing its idea on idle control.

The trumpet has nothing to do with the idle on petrol as it is only a silencer.
The throttle blade provides the restriction.
You have made an air leak.
Regards Philip A

Originally Posted by PhilipA

The trumpet has nothing to do with the idle on petrol as it is only a silencer.
The throttle blade provides the restriction.
You have made an air leak.
Regards Philip A

That's what I thought too.... I'll take another look. Possibly the accordion tube has split in a place I can't see. It's very strange just putting a couple of fingers over the inlet to provide even the smallest hint of restriction cause the idle to drop back and work correctly.

seeya
Shane L.

Have you cleaned up around the throttle blade and outlet for the engine ventilation.
You should also check that the small pipe that leads from the T piece into the plenum has not split , or the t piece hasn't broken.


Your leak will be AFTER the throttle blade.
Maybe the bypass which you screwed out was partially blocked or the stepper is sticking.
You should set the Kerb idle to about 550RPM by blocking off the outlet from the throttle body to the stepper ( and the stepper inlet) and screwing the bypass in and out AFTER you have cleaned the throttle blade and surrounds.


The stepper should then automatically control the idle to about 700RPM. If not then new stepper.
Regards Philip A

I did pull the stepper motor crankcase breather system apart and check it all about 6months ago ... It all worked and was nice and clean.... This all worked perfectly ... until I cut that air cleaner trumpet off. I will check it all again as soon as I get a chance I can't say I'm suprised, that inlet trumpet will be there for a reason. Surely it just can't be to dampen the inlet sound

Mechanics bugger stuff up just as well as I do too. A mate dropped of his old car with me a week or so back... I started it up and it would barely run when cold and was lumpy as hell. When I popped the bonnet and checked I felt like headbutting a brick wall. All the crankcase recirculatoin has been messed with. It's all been bodged together with hoses and joiners ... I bet they have bypassed the auxilary air valve too ... that's why it wouldn't run when cold. I just don't understand WTF any mechanic with half a brain would do this. The factory plastic joiners in the crankase recirculation setup has metering orifices in them... ie: they close down to about 2mm from the 15cm hose to restrict amount of intake suction when the throttle is closed. Why ... just ... why I'm sure he paid a lot of money to a mechanic to make this mess.

Back to the Rangie. The brake controller is hooked up, I fitted two of those temperature controllers to the thing. One to the trans cooler outlet, and one to the top radiator hose ... As close too the factory sender/housing engine side as possible.

http://www.aulro.com/afvb/discovery-...larm-39-a.html

I was expecting it not to show much useful until the engine hit about 80degrees and the thermostat opened. Guess how useful the factory temperature gauge is With the coolant at 30degrees... the factory gauge is dead center .... the damn thermostat is fully open at 50degrees (the engine won't get any hotter than this ... yes I think the new gauge is accurate as I can hang onto the top hose and it doesn't come close to burning me). At 50degree the dash gauge shows still dead center. If I turn the engine off for 5minutes and let some heat soak increase the coolant temperatue in the block ... when I restart the coolant temperature is 75 degrees..... The dash gauge is still dead center. As soon as you start the motor and the coolant circulates it plummets back to 50degrees.

So the dash gauge is absolutely useless and tells lies. I know it shows the same reading for the 30->75 degree coolant range.... it wouldn't suprise me if at 100degrees it still showed "normal" --- dead center of the gauge... and the thermostat is either no good, stuck open or missing from this engine.

seeya,
Shane L.