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MG MGF Technical - HGF new gasket, rough tick over

I have just completed a headgasket replacement, (+ 3mm hole drilled in thermo-stat), & cam belts changed. On my 98 VVC (MEMS 2J engine). On restarting, the engine started ok but tickover very rough runs at 1300rpm (will not adjust lower) ,and it doesn't reduce to it's normal 850rpm when up to temp. Driving car at 2000rpm + the engine is smooth. Engine tick-over ok prior to gasket replacement.Spark plugs ok.
Has anyone out there had this problem or can suggest a cause I'd be gratefull
Ron
Reading
Ron

Sounds like fail save mode idle from the ECU. (If there isn't any VVC mechanical problem)
Check the sensor connections, special to the IAT and ECT sensor. The other side also, of course (ECU connector).
Dieter

usual fault that causes high running is disconnected or broken temp sensor, unplug it to see if the fan comes on.

Rough running is most lightly to be the cambelt out by a tooth.

What do you mean by 'will not adjust lower' there are no adjustment points, only one screw in the throttle that is factory set and should not be touched (!)

Else, there could be a vacume leak, have you made sure that all the pipes are back where they should be - especially the ECU sensor, the camcover and the power brake tubes.
Will Munns

One other possibility - there are a couple of plugs on the top of the VVC head - the bit that runs the VVC adjustment mechanism - that can be swapped over accidently on earlier MGFs (but changed to avoid this potential problem on later versions).

Check that all the loom plugs are correctly connected before checking cam timing; timing should not have gone out if you locked the cam wheels with the correct tool.
Rob Bell

Top man Rob, swapped over sensor plugs now runs perfectly. Many thanks

Ron
Ron

just done one it was rough for the first 5 mile, then it was o.k.
r.f.j. griffiths

This thread was discussed between 03/10/2006 and 10/10/2006

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