Will my stalling car fail its MOT?

Jimbosmithers · 26 Apr 2011 at 01:35

Hi all, (first thread: be nice)

I drive a Mk1 1.8 Focus. MOT is due in June and it might fail.. or it might pass.

Everything on the car is fine apart from one slight issue...

If i go above 40 mph in about 3rd/4th gear and drop the clutch or engage neutral the engine will die. It only happens when going from mid/high revs to idle quickly. If i allow the revs to drop slowly, or go from say 5th (so low revs) to idle, its fine.

I can live with it because i know exactly when its going to happen and know what to do to stop it happening, but its annoying. Most likely the idle valve has gone. I've already tried cleaning it and replacing stuff like crankcase ventilation hoses etc. but i think its coming down to either the idle valve has gone, or the evaporative emmisions control system has summit wrong with it.

Being a cheapskate student with a dissertation due shortly... I might not have the time or money to fix it myself, so question remains... is my stalling car likely to be picked up on an MOT or should i fix it first?

OpenToSuggestions · 26 Apr 2011 at 01:38

You could always ask a garage in advance.

I have no doubt that a backstreet garage would 'oversee' the issue anyway.

MikeHiow · 26 Apr 2011 at 01:39

If it happens repeatedly during the emissions test, they may just fail it - I'd give it a go though.

zipp0r · 26 Apr 2011 at 03:00

remove it and clean it :/

thewanted · 26 Apr 2011 at 06:56

Jimbosmithers said:
I've already tried cleaning it and replacing stuff like crankcase ventilation hoses etc.

zipp0r said:
remove it and clean it :/

Read much?

Lopéz · 26 Apr 2011 at 07:16

Only if it interrupts the emissions test procedure.

It's been a long time since I put a car through one of those and I can't remember the order, I was sure it was fast idle followed by normal idle, if the engine stalls as it drops to slow idle I don't know if that interrupts the process or not because it never happened to me when assisting on test!

realscot · 26 Apr 2011 at 07:42

Your right Lopez, it might stall the once while returning to idle, however you'd expect any half decent tester to just start it again and let the test finish. I don't know about others but our machine allows 30 seconds for the idle to settle before checking the idle emissions, plenty of time to start the engine again.
As said above, when booking in the car for the MOT ask the tester should it stall, is he happy to start it again and finish the emissions test, if not take it elsewhere, and tell him so.