yet another question lol

[rachaelk]

ive got a bad missfire on the car and i think its ht side of things cos as soon as your on motorway it drives like a dream, ive taken the plugs out and they dont look too carboned up but im gunna change them and the leads too my only question is does it have a dizzy cap and rota or a coil it looks like a dizzy cap but its coming up with both at pages (this is why i married my husband he kept sending me the wrong parts lol) its an N reg 1995 can anyone help me.

thanks guys

rach

[Geoff.F]

Dizzy and rotor.
Geoff F.

[rachaelk]

geoff your a star thanks

[Rob Bell]

And it's pretty easy to do: http://mgf.ultimatemg.com/group2/common ... tering.htm

[rachaelk]

thanks rob, right it cant be that cos ive just changed dizzy rota and plugs and leads its a bit better but still ticking over ropey so whats next guys

[Rob Bell]

What distance did you gap the plugs to?

Is this a problem only noticable at idle, or is the engine also down on power?

What is the idle speed?

Sorting out the basic ignition components is certainly a job well done - but it does start to suggest a problem elsewhere. If ignition, then the only component not changed is the coil. These are pretty reliable in service, but might be worth thinking about. Is there a decent spark now?

Sensors can cause problems - particularly the crank position sensor. Others to think about are the MAP sensor and lambda sensors. I'd check connections (vacuum pipes in the case of the MAP sensor, as on MEMS1.9, the MAP sensor is built into the ECU box).

Thereafter, I'd like a compression check - is there good compression on all cylinders?

The other area to consider is the fuel system. Is the fuel filter blocked? Is the pump on its way out (more likely to present a problem under engine load rather than at idle). Are the injectors working or on their last legs?

Sorry - seem to have presented a long list rather than anything specific - and I need also to mention the potential for inlet manifold leaks to cause mayhem to smooth engine running... Well, this is certainly a juicy problem for a Tuesday afternoon!

[rachaelk]

bloody hell rob im only a women lol, i dont think it has anything to do with fuel as its perfect when on the motorway the thing i did notice is that the exhaust is leaking a tincy bit but hey ive done my best for a bird, did i mention that the oil and water are starting to mix but its going in for the head doing on monday i just wanted to play really oh well let the garage sort it.

thanks for all your help

[Rob Bell]

Only a woman? Well that means you can fix MGFs while simulataneously working out realtivity from first principles. We chaps can't multitask!

If the gasket is suspect, then I suspect that the problem may reveal itself in a compression test - one or more cylinders may be leaking which would explain the misfire.

Do keep us posted!

[rachaelk]

hahaha damn right rob lol, just to update i took it out last night and its bloody perfect, it didnt miss on the motorway but it did round town, now it doesnt do it at all unless its on tickover and its only now and again and very slight so i think ive fixed it, my neighbour is well impressed cos he keeps slagging it off (hes a fanatic mini fan) but he doesnt like it when i tell him my mg is related to his gorgeous old rover mini, im just really excited and i cant wait to take it to the garage cos the 1 mile drive will put a smile on my face.
i was supposed to take it to another garage yesterday to get it all done but through the grapevine ive herd that he doesnt do pressure testing but yet tells the customer that he has so im taking it to where i take my landrover cos there great and i trust them completeley.

so hey ho ill be on the road in no time.

[Rob Bell]

Best take it somewhere you trust - part of the reason I get my car serviced 100 miles away at Tech-speed! That, and they're a good bunch, and it's a nice drive!