Weird - Idle Revs increase when gear selected, throttle off.

[v8dve]

Hi,

This has recently developed on my 2004, no work carried out recently.

Tests carried out with no hand on throttle at all....

Idle when hot in N - 1100

Idle when Clutch in, gear selected - raises to 1500

Have tried different gears and same thing happens.

Put it back into N and revs drop back to normal whether clutch is in or out.

Have tried putting into 2nd and revs increase after a slight delay.

If I just leave it in N it'll just keep idling fine.

If anyone has any ideas what may be causing this I'd be most grateful.

 

[SLK50]

I have a wild theory: figure out a way to eliminate the neutral

switch from the equation and run the scenario again.

Could there be an electrical load only present when

the neutral switch is on?

 

[puppychow]

Clutch switch perhaps?

 

[v8dve]

Excellent ideas there guys, will bypass both switches one at a time and see if either makes any difference.

I'm almost at the point of thinking something in the gearbox is tight when in neutral and actual normal revs setting would be when in gear. But if the idle was set for that level it would stall when neutral was selected....

Not sure it would be the clutch switch as nothing changes when clutch pulled in, only after gear is selected. But will still check both as who knows.

Will check it out over the next few days and keep you posted.