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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?

Cheers,
Tim
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

Mike,

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

Cheers,
Tim
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
john
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.

Cheers,
Tim
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

This thread was discussed between 31/07/2009 and 05/08/2009

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