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MG MGF Technical - Un-even running -> NOW GLOWING RED EXHAUST!!!!

Dear Freinds,

I left a thread this AM titled 'Un-even running' ( thanks to all who replied ), which talked about my 99 VVC 'F' that had a slight judder with slight accelerator pressure.

Well i have just got back from the MG specilist ( Somewehere near Cambridge )that carried out the work a wee bit pisssed off.

Aparently they have cleaned the Top Dead Center sensor and reinstalled it. They then preceeded to take the car for a test drive. I waited in the workshop chatting. Upon there return i noticed the car sounded like a tractor,and the whole exhaust system including cat and Mike Satur SS exhaust was GLOWING BRIGHT RED.

So, i think to myself 'WHAT THE HELL IS GOING ON'. You would assume that if the car did not feel right they would have stopped and slowly brought the car back.

I need some advice, what shall i do. My Mike Satur Mirror Polished exhaust is now black form heat and the tail pipes are yellow, i have only had it 2 months.

What engine damage could this have caused !, the engine temp must of been through the roof.

My feeling is that the car has been caned on the test drive and something a little more serious than a sensor has broken.

The workshop have ordered a new sensor and this should cure the problem ???

Please, what are your thoughts. My head is spinning and i am not sure what to do !!!

P G Olney

The exhaust glowing red is truly worrying alas on this note I can't really comment others will be able to give more knowledgeable advice.

However on the matter of the discoloured back box and tail finishers I can suggest good old fashioned Brasso.

My own MS exhaust shows the brown discolouration, certainly exacerbated when the engine is thrashed, but a few minutes with the Brasso brings it right back up to the mirror finish. Tail pipes can be treated the same.

The exhaust situation can be remedied and I hope you find that the engine hasn't suffered.

tim woolcott


I think I would demand re-imbursed for the a hell of a lot of shouting and balling. Demand your next service free and if none of the above is given, go to the local paper...what they have done to your F is beyond words. Me not being technical cant comment on damage but Im sure its not very good.
We're all behind you !
David J

Glowing exhausts generally indicate retarded timing or exhaust valves sticking open or burnt, both of which allow fuel to burn in the exhaust system.
George B.

too rich mixture can cause the cat to overheat !
misfire on VVC's can do this and caused fires and burned out Elises and 340R's , but then their body is plastic !
I think you've been lucky so far.

Bob vanM
Bob vanM

god what a nightmare for you, a long way for you to go from Gwent up Cambridge way, if your looking in near future for someone good, MG Newtown Motors Cwmbran,was recomended to me, and have recently had 24k service done by them and they do seem pretty profesional,and more local to you as from Gwent lIke me, good luck, Dave T6 DCM.

Thanks chaps for the replies,

I have been chatting to a freind at work and he feels it is worth getting a reading of the compression ratios to ensure that the valves and rings have not been damaged, what do any of you think ?

If they increased the mixture to compensate for rough running then any unburnt fuel will be ingnited in the hot cat and could destroy it, burning of the platinum. Get them to check the emmisions which would show up a knackered cat and if necessary get a new cat out of them.
Was it 'popping'on decceleration?


A compression test would be worth doing. If any pot is low try squirting oil into the cylinder and if this improves things then your rings are suspect. I would be most worried about your cat and an emission test would also be a good idea. The other thing I would worry about is if this event starts the dreaded HGF. I've never seen a red hot exhaust, something must be drastically wrong.
Best of luck

Saw a documentary on Rolls Royce, which documented them building the car up from scratch.

Once the engine was assembled, they ran it at high revs, for hours, and the whole exhaust from the manifold back was glowing bright red.

Makes me wonder, if they do this to engines before they are put in the car, why do they say don't exceed 3,000 revs for the first 1,000 miles etc. When the engine has gone through the most sever tanking its ever going to get before it even leaves the factory.

(slightly off topic, but even rolls royce engines make the exhaust glow after a sever thrashing.)

Thanks for tip on brasso, going to buy some today ;-)

paul weatherill

>why do they say don't exceed 3,000 revs for the first 1,000 miles etc
do they? or is this the running in? I asmume there is no load on the crank?

Will Munns

PG, I doubt that the workshop concerned was caining the car too hard, because the glowing exhaust can be explained on the basis of the ignition problem that I believe that George has correctly pin-pointed.

The ignition map sounds to be way out - I would not drive the car any further until the problem is sorted out to avoid engine damage (burnt valves, blown gaskets, cylinder head damage etc).

I presume that the place in Cambridge is the place I am thinking of? Haven't they got access to testbook?

Assuming that all the things that I mentioned on the other thread have been attended to, my next step would be to swap the MEMS with another unit to see if this solves the problem.

Having a hot exhaust should not, per se cause problems, although I am not sure how well the catalyst tolerates extreme high temperature?
Rob Bell

If the exhaust was glowing red then it would also be worth looking at the bottom of the rear bumper to see if the heat has distorted the plastic at all.


Jim Hosking

<<do they? or is this the running in? I asmume there is no load on the crank?>>

yup will was "running in" i was refering to.
not had to do it myself, as the only new cars i have had have been company cars.

don't know if they put a load on the crank, i would assume they would, but don't know.

paul weatherill

>>don't know if they put a load on the crank, i would assume they would, but don't know.<<

I'd presume that there would be - would not the engine be run on a test rig/ dyno?
Rob Bell

Wohow... you must go mad if you see and hear the result of those professional craftmen.

regarding the juddering: are the revs bouncing (700-1100-700-1100rpm) when the acclerator is pressed very gently? Does the problem only occur after some while of driving, or could it start just in the beginning of your journey ? Could the problem be 'solved' by switching the engine off and back on again?

regarding the terrible sound and red exhaust: check the compression ratio's and check for abnormal noises once the car has been fixed (for broken seals, gaskets).

Take your time to get your car sorted, don't be too happy when it looks ok, be carefull.

and good luck

Glowing red exhaust = bent or badly burnt valves
head off time!!

I seem to remember that (in the dim distant past) someone called Dirk had a glowing exhaust. It was never exactly resolved what caused this, but incorrect timing was one possibility (caused by a 'chip'?). Seems to me that your 'specialist' has initiated a similar outcome, maybe by screwing up the TDC sensor.

Dirk's car eventually died, HGF, melted, imploded and caused endless discussions when he replaced it with an M3 dirk-extender.

You have been warned.

N837 OGF

Don't even run engine or drive it period! At least until you know the problem and possibility of further damage. If you are a memeber of one of the motoring organisations, AA RAC etc or clubs MGOC, MGCC etc engage them asap. If not then one of the garage professional bodies. Drop a formal letter to the garage outlining your complaint. IIRC the requirement is products or services to a 'satisfactory standard' this is clearly not. I think you can claim consequential damages hence get a letter in and take professional advice. If you continue to use car when you know there's a problem your case is weakened. Also may claim you caused the damage by not letting them reasonably fix it etc etc. Get professional advice - fast.
Ian Walker

Cheers Ian,for the advice unfortuntely it was the MGOC that carried out the work!. They have agreed to replace the exhaust FOC. I have recently taken the car to Brown & Gammons, what a waste of time that was. They put the car on test book. I waited 6 hours to be notified that they could not get test book runnign because all their CD's are scratched. Well all i can say is that neither the MGOC or Brown & Gammons will ever get my business again. Especially after reciving very bad advice from both places. I spoke to Mike Satur who put my mind at rest, he actually come up with a plasuable reason why my car is juddering at idel and at low speed. It great to know that after all the mg specialist there is at least one person who is willing to listen and will do a good job unlike the MGOC and Brown & Gammons. I am hoping to drive up to yorkshire next week to get it sorted. The root cause sounds like it is the stepper motor.

Cheers Paul...

This thread was discussed between 14/11/2002 and 22/11/2002

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