Idle Problem!

[scott-stainton]

Hi guys!

Im having a problem with the idle speed, when it starts it jumps straight to around 1600RPM, and it is happy to sit there until you rev the engine, after that it will rest at 1600 then jump to around 2000, and bounce between the two.

If I block the ISV, the engine will drop to 800RPM, and when i release the ISV again it will stay there, until the engine is revved again...

Throttle body is in good condition, clean
ISV/ICV is good and clean

The MPG sits at 0 but i can't find how this calculation is made, hopefully someone knows and it might point to something at fault

Thanks,

Scott

[scott-stainton]

Bump! still having this problem

[LR5V]

This an ABF? -Does the ISV buzz when the ignition is on?

Sounds like you have unmetered air entering the engine allowing it to idle higher than it should and too much air for the ISV to handle.
Check all the vacuum pipes & inlet manifold gaskets for leaks.

[scott-stainton]

This an ABF? -Does the ISV buzz when the ignition is on?

Yes sorry it an ABF.
ISV doesn't buzz when ignition is on but removing/disconnecting it has no better effects

[LR5V]

ISV doesn't buzz when ignition is on but removing/disconnecting it has no better effects

In general they do buzz or vibrate, but some people say theirs doesnt and still works...
I would take the ISV off and give it a good clean with carb cleaner and try it again.
Next check if its getting power.

Mine had this sort of issue, stalling when cold, the same mad revving thing too -mine was leaking inlet manifold gasket, I had stripped a few threads in the lower manifold from over tightening the upper manifold bolts -my bad entirely

Until I worked out that it was the air leak I used a temporary fix was something jammed into the pipe that comes straight from the airbox, the idea is to block most of the air getting to the ISV. this worked but was still over revving on idle, used a cable tie to clamp down & reduce the amount of air even more - quite good you can increment the constriction by each click on the cable tie till I was on a relaxed 800-850 rpm.
Worked quite well, apart from on cold winter mornings, the engine would die pulling up at junctions.