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MG MGF Technical - What are the symptons of a warped TB

Can anyone say what the symptons of a warped TB is as I am having engine problems and have replaced the normal parts taken it to a dealer and still problems.

I know the symptons are sticky throttle and eratic idling. Mine has eratic idling but also has hestsitant acceleration which seems to be exagerated when the weather is hot and was wondering whether this is the TB.

Sods law said when it went into the dealer the weather was damp and much cooler and did not show any problems but since the weather has picked up it is showing signs of problems.

Tom
Tom Randell

Sounds very plausible to me I've certainly heard idling problems and a very slow decrease in revs being attributed to the TB previously. Presumably you've got an MPI (only one fitted with the plastic Metro TB), either get yourself a 52mm metal one, or I'm sure someone on here will offer you their old plastic TB that they're replaced.

Darren.
Darren

Darren, good idea regarding a swop - should help nail down the problem to the TB ... or not as the case may be.

I know that Scarlet has a plastic TB going spare Tom - and I bet there are plenty more around...
Rob Bell

Could also be air geting into the system after the throttle, any reports of this happening by anyone else?
Will Munns

Darren,

Re <<Presumably you've got an MPI (only one fitted with the plastic Metro TB)>>.

The VVC also had a plastic throttle body.

I got a metal TB from a scrap yard for £24.

Bruce
Bruce Caldwell

You learn something every day! Thought it would be metal, like the inlet manifold on the VVC

Darren.
Darren

I am tempted to just go for a new Trophy TB so even if it does not solve the problem it should be an improvement.

Tom
Tom Randell

Tom, As per my thread regarding fitting TB the symptoms you describe suggest IMHO air leaking into the system past the butterfly valve. Try slacking the throttle cable off a touch to ensure it completely closes - you should be able to do this without any loss of 'pedal feel'. Try also checking the O-ring seal for damage or dirt and then tightening the four securing bolts to ensure a good seal. Like I said earlier, I found these bolts to be surprisingly easy to undo and it wouldn't surprise me if air was able to leak past the seal. The plastic TB seems to be extremely robust and I find it hard to believe so many people complain of a warped TB.
The hesitant acceleration is a tricky one - I can't see how a leaking TB would cause this. I'm not an engineer, so I hope my limited knowledge can help!
Phil

Phil,
If there is air leaking into the system them MEMS will try to stabalize the revs by playing with the fueling, this might cause a acceleration problem as the map will be a little screwed
Will Munns

This thread was discussed between 19/06/2002 and 20/06/2002

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