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MG MGF Technical - Tickover

Good afternoon all.
Is there a simpleway to adjust tickover ( idle-speed ) on the F and TF ? Any advice gratefully received.
mike clements

I believe not. Idle speed is controlled by the ECU using the Idle Air Control Valve (IACV) - this basically bypasses the throttle body and allows air into the inlet manifold. If you have problems with idle speed, check for split hoses, etc and confirm your throttle butterfly is closing fully. You could also have a dodgy sensor (especially temperature) causing an incorrect idle speed. Is it too high or too low?

T Jenner

Thanks Tim,

My wife's TF seemsto have slightly low idle speed which causes stalling sometimes in traffic and a red face for her! I will check hoses etc. and if they are sound then she will have to use a judicial right foot.
Mike Clements


Check the usual service items - air filter, plugs and leads especially.

T Jenner

Hi Mike,
Yes there is,
If im right you reset the ECU's air/fuel senser (Idle speed) which inturn should reset the tickover speed.
You turn the ignition to on, then pump the excelerator pedel 6 times in quick succestion, i think its 6 times within 30 seconds, then start the car and leave on tickover. (Bandit or Rob etal, will know off the top of their heads how manytimes within how long)

the car then hunts for a bit, then gently in stages drops the RPM down to the 750-800 mark.

Most people who've fitted a 52 mm TB will have had to do this to reset the idle, and as the ECU "learns" as you drive, if like me your a bit spirited it tends to act like its running rich, then it needs reseting every now and then.

hope this helps
J E Reed

Good point, John, definitely worth a try. However, note that this only resets the throttle position sensor (TPS), it won't "adjust" the idle speed as such or directly alter the air/fuel mixture. The TPS is just a variable resistor attached to the throttle butterfly - it's used to tell the ECU the position of the throttle (and, if I remember correctly, the dynamics of movement - opening, closing, quickly, slowly, etc). The ECU uses this information to adjust the fueling and ignition timing, so in that respect it might help.

T Jenner

There is an adjustable idle stop on the throttle body, but to be honest, this never usually needs adjusting; the problem with the idle probably points to a problem else where.

Some of the problem areas have already been pointed out - and I think that your description of the TPS reset procedure sounds about right John :o)

The Idle Air Control Valve is another suspect not already mentioned - and can become gummed up with oily fuel deposits over time. Its located on the inlet plenum and is held in place by a couple of bolts. Pretty straightforward to remove and clean (use petrol or white spirit and dry thoroughly - or you could use carb cleaner spray)

Consider the IACV has an electronic throttle that controls idle speed, and you can see that a problem with this valve can cause problems with idle speeds.

Another potential problem could be a leak in the inlet vacuum caused by the inlet manifold gasket or a loose/ damaged vacuum hose. Worth inpsecting in any case (although not that easy given the limited space we're blessed with!)

Hope this helps!
Rob Bell

Wish to resurrect this topic please.F VVC was used for a 100 mile run over a week ago.No probs.Usual drive.

Came to use the car yesterday a.m. after it had been in the relatively cool garage for the week.Bearing in mind it has been very hot this last week.

Started her up and immediately the tick-over was up to about 2000 revs from it's usual 850-900.It did slowly come down to about 1500 and when out on a 70 mile run yesterday(still very warm out there)it would at times come down to normal tickover when slowing right down for lights,traffic etc but went back up again on slow acceleration.

Obviously,this subject has been raised before but my basic question is,is the tick-over heat sensitive.I have read the info about IADV ,ECUs and inlet manifolds etc but most of this leaves me a bit cold as ,basically,it is so difficult to see anything or to get at anything,Where does the actual throttle cable go from the pedal to the engine?If you look at the engine top( with the grille off) there is a cable operating a quadrant and spring which I have oiled and are quite free.What is this?Please someone tell me the whole set up is heat sensitive and will go back to normal when we all cool down.Otherwise is it another expensive trip to a garage for a hood up/engine cover off job?
M Blencowe

This thread was discussed between 31/07/2009 and 22/07/2013

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