High Idle

Author
Discussion

fat80b

Original Poster:

804 posts

160 months

Friday 15th March
quotequote all
Having taken the Tuscan out last weekend and it running perfectly, I went to use it mid week to find it will now only idle at 2500 rpm.

Under load, it will drop to ~1800 as a minimum.


Any clues as to what might be happening? / if there might be a simple way to restore its recent happy behaviour.



PetrolHeadPete

629 posts

128 months

Friday 15th March
quotequote all
Did you try physically lifting the throttle pedal back up ?

fat80b

Original Poster:

804 posts

160 months

Friday 15th March
quotequote all
PetrolHeadPete said:
Did you try physically lifting the throttle pedal back up ?
I did have a go at that - didn't seem to have any effect - I have had throttle cables snap in the past so it could be cable related but I get the feeling it is something else / stuck butterflies?

I plan to stick my head in the pedal box tomorrow to see if there is anything obvious.

nawarne

2,722 posts

199 months

Friday 15th March
quotequote all
I've had something similar.

I'd check the clevis pin 'R' clip and the clevis yoke . What I experienced was that the pin and R clip fouled on No.3 throttle body/flange - effectively holding the throttle open. IIRC, I cured it once and for all by putting a washer under the 'top-hat' end of the clevis pin thereby preventing the pin 'walking' to the position where it was fouling the TB/flange.

There has been a recent thread regarding erratic idle rpm, and the OP advised that he replaced the return spring between the clevis and the cable bracket. Essentially a stronger spring ensured (all) the TB butterflies returned to the proper idle opening position.

Nick

Edited by nawarne on Friday 15th March 14:15

fat80b

Original Poster:

804 posts

160 months

Finally got round to taking a look at this.

I spent some time trying to see if the cable was fouling somewhere near the pedal end first and it all looked OK.

I then thought, I'll fire it up and see if it is still misbehaving before going to the trouble of taking the bonnet off.

You've guessed it. No longer showing the symptoms. Idling normally at about 1200 rpm which is roughly where it always used to be.
Advertisement

quint22cp

10 posts

10 months

Mine normally idles at 700 - 800 RPM
1200 is a bit high.

Maybe you need to reset the throttle stop it is between 123 and 456 throttle bodies where the cable terminates.