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MG MGF Technical - Sticky revs

Hi guys, on the way back from the pub tonight I noticed that my revs didn't drop if I dipped the clutch! Come to think of it, the throttle has been a bit sluggish returning to idle lately, but didn't think much of it.

Any ideas? I'm hoping that it will be better in the morning once everything has cooled down so I can use it.

There is always something to spoil a good evening!

Chris
R585 ERO Abby
Chris George

Throttle recalcitrance is a common problem with the K series due to its plastic throttle body, this can become distorted with heat causing it to stick, the clip which retains the inlet trunking can also be overtightened resulting in distortion of the throttle body. Lubrication with WD40 can help in the short term, check the clip too to make sure it is not overtightened. Aluminium replacement TBs are available from thrird parties to eradicate the problem.

Other causes could be an air leak or a sticking IACV,or a sticking cable. I would check the throttle action when the engine is hot by having a friend plant the throttle a couple of times (engine off) while you check for freedom of movement/returning.

Dave
Davdi Andrews

It's no better this morning, if not worse. It doesn't go below 2,500 rpm unless it's under load (which can't be good for the engine or the gearbox) and gets stuck at the highest rpm I use unless I force it down using the gearbox.

Just booked it in to get it looked at, but not til next tuesday.

Chris
Chris George

Chris

Have you fitted a K&N filter?

If so do as David suggests with regard to the throttle body as this is a known cause of sticky revs. If you haven't fitted a K&N and your garage hasn't replaced the original clip with a worm drive (Jubilee) clip then get it checked for other things.

Ted
Ted Newman

no K&N fitted.

> If you haven't fitted a K&N and your garage hasn't
> replaced the original clip with a worm drive
>(Jubilee) clip then get it checked for other things.

Such as? I suspect it has the original clip on it... but that is only an assumption as there has been no mods to the engine...

Chris
Chris George

A while back one of the sprinters had a very similar problem, which he found, when he stripped the TB down to be down t the depositation of black gunky stuff (of unknown aetiology!)

He cleaned the TB up with some petrol to immediate success- better throttle response, economy, power etc.

Worth a look me-thinks. One of those carb cleaner aerosol sprays (Halfords) may do the trick if the thouught of disassembling the TB does not fill you with joy ;o)

Also worth checking is the correct function of the throttle cable- make sure it is not sticking, and the throttle is able to easily shut close.

Rob
Rob Bell

I checked the throttle cable at lunch time, and it moves freely, plus wiggling the throttle linkage on the TB seems to have free'd it up a bit. Does seem suspiciously like it could be gunked up.

If the weather is fair tommorrow I might have a look at it (no garage you see!).

BTW it has also got the original clip on it, so that rules that one out!

Chris
Chris George

This thread was discussed between 05/04/2001 and 06/04/2001

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.