O-rings and the like

[topgear]

You amy recall from previous writings in the forum that i was having problems with my VDP wanting to stall, and feeling lumpy after 10 minutes of warming up, around the time the autochoke should disengage. The o rings on the stepper motor were suspected, and having got a kit of metric o rings, i started to undo the screws on the stepper motor. Of course, the usual problem was evident, the screws were stuck, so electric drills, wd40, releasing fluid and finally an angle grinder put pay to this little problem. The stepper motor was off, the o rings looked a little weak and floppy compared to the new runs, so renewed them and put it all back together.
The situation now is that the cars performance has improved dramaticaly, there is so much more power under the throttle and it does not appear to be sluggish as it was on some occasions before. however, the problem of the stalling and lumpyness after 10 mins is still there! I have also renewed the vacuum switch, so can rule that out.
Does anyone have any ideas as to what the problem is?

Cheers,

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Top Gear, Top Thrills

[MaestroMatt]

Could it be anything as simple as the fuel mix in the carb being too lean? Though, if you are smart enough to change the O rings, you have almost certainly thought of that!

[MGTurbo]

Glad to hear my recommendation of the O ring's worked. As already mentioned, it could now be running lean, you will have to make adjustments to compensate now that your using less fuel.

Gareth

[E_T_V]

You'll likely need to retune the carb as I think someone mentioned to compensate for the new o-rings.

A couple of other possibilities spring to mind:

Petrol or water in the vacuum system. Our old 1.6 S had a little reservoir for the vacuum just before the ECU (others didn't) and this used to trap petrol leading to lumpy idling (A quick blow out sorted it out)

You might need to reset the stepper motor. I think there is a procedure for this somewhere, but it basically involves unplugging it plugging it in and turning the ignition on and off a few times to "exercise" it.
It might need a bit of lubrication too.

The hot/cold air flap thingy (dunno what it is properly called) is it sticking or leaking air into the system? if it is it might be upsetting things as it switches air sources.

If there is a throttle switch check it is working.

Unplug the fuel cut off soleniod (see if that makes a difference - it shouldn't but it won't hurt to try)

Check the ignition timing and advance is functioning correctly.

Hope some of this might help

Cheers

Dan

[topgear]

Many thanks for all your helpful suggestions. i should be able to have a look at it tomorrow, so ill let you know how i get on!

Much appreciated!

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