Delay returning to idle

[apk]

I know this is an idle problem, and I will get told to check the stepper, but this has been an ongoing problem, spanning several services and dealer stepper motor cleans, so I'm going to brave it and ask....

Griff 4.3 (K) which doesn't return to idle until the car is motionless for a couple of seconds. It stays at about 1700 rpm, then drops to normal idling without any hunting.

The main problem this causes is moving in slow traffic, it stays at these higher revs and drives the car without touching the throttle.

Any clues where to start looking?

[vodkakid]

i get the same thing and have cleaned the stepper many times with no effect so i'd quite like to hear some ideas to (sorry im no help to you) does yours do it all the time or just sometimes????

[apk]

It does it all the time, but when things get really hot it starts to idle higher.

[beano500]

At a guess - I would suspect a sensor. The reason? My 500 has similar symptoms. But only when the coolant level is getting low. In fact I often find the early onset of idle problem is my cue to get under the bonnet

I believe that with airlocks getting into the system the sensor is fooling the ECU into thinking the engine's cold.

I could be talking complete balderdash, bilge, bunkum, claptrap, gibberish, poppycock and tommyrot. It wouldn't be the first time

[Roy C]

More "balderdash, bilge, bunkum, claptrap, gibberish, poppycock and tommyrot" - try cleaning the air vanes.

[vodkakid]

spooky mine went higher than it has done before yesterday and it was a damn hot day !!
ill get under the bonnet and check the water level

[apk]

Roy C said: try cleaning the air vanes.

What/where are the air vanes?

[Roy C]

apk said:

Roy C said: try cleaning the air vanes.

What/where are the air vanes?

The air flow meters (assuming the Griff has them) between the filter and the plenum. Use carb/injector cleaner.

[GreenV8S]

If the ECU speed input was playing up, that could cause this sort of trouble. But you should go clean the stepper motor AGAIN just on general principle!

[apache]

there's a 'hot wire sensor' in the airflow meter, but I wouldn't play with that.
I've heard mention of a 'road speed sensor' that (I think) keeps the revs that bit higher than idle for smooth gear changing, when coming to standstill it shouldn't work, could be something to do with it

[apk]

apache said: I've heard mention of a 'road speed sensor'

Cheers, a quick google for "tvr road speed sensor" turns up a link to:
http://ourworld.compuserve.com/homepages/Peter_Beech/TVR/injspec.htm

"All of this means that a faulty road speed sensor can make the car stall at junctions, stall or over-rev when stationary, ...."

I'll have a fiddle with the stepper, and if that doesn't work, get the dealer to have a look at this.

[rubyV8S]

Had exactly the same problem on the S, very un-nerving coming off the gas but the car still 'driving on'!

If not the stepper motor, reset the base idle ( see the bible) and possibly the fuel mixture too rich,adjust the screw on the airflow meter.

Mark

[sagalout]

My Chimara does this a bit too. I thought "they all do that sir". Believe it's a throttle damping thing in the computer stuff

[mav]

Hey...APK
Its all very well cleaning the stepper (which is definatley where I'd start) but 1. Make sure the stepper seat in the plenum is clear of carbon deposits and 2.(that old thread again)It is vital that you disconect the ecu when you've had the stepper out!

[homer]

Who, why, what says you have to disconnect ecu ?
Last time I saw my ecu was when I changed the battery two years ago. Many stepper cleans since everything running fine!

[jigs]

It's the road speed sensor that keeps the revs up when car still moving. Maybe the sensor needs replacing if it's holding onto revs for too long?

[shpub]

jigs said: It's the road speed sensor that keeps the revs up when car still moving. Maybe the sensor needs replacing if it's holding onto revs for too long?

Well the sensor also supplies the speedo so if this was the case, the speedo would be registering a speed while the car was stationary. If the obvious things have been chceked then it is time to see a professional.

[clarky5150]

Ok, so can anyone answer this one for me?
To adjust the enrichment which way does the allen screw go i.e clockwise = richer etc and secondly is this adjustment 'the more you turn the more you alter' or is the screw free spining on a sensor because mines a mile out, no time to RR session soon and i know you can turn the screw round and round for ever.
Thanks, Shaun.

[GreenV8S]

Which allen screw?

[clarky5150]

on the air flow sensor.