At 04:30 PM 1/24/2011, John Rodgers wrote:
>with this - insist that the difficulty is the throttle switch. The
>settings for the thing is critical and wear and whatever can really foul
>things up. This is a sorely neglected maintenance point. Nobody checks
>it  - they just drive until the engine sputters and quits - then they
>"holler for the calf rope!"

If the closed-throttle switch on a 1.9l doesn't open when it's
supposed to you'll think you're in a giant slow paint shaker when you
accelerate from idle.  I don't think failure to close will actually
make that much noticeable difference (what should happen is that the
engine will shut down until you get below x rpm, but you won't notice
it not doing that unless you're monitoring the injectors).  Neither
failure to close nor failure to open will stop it idling.

On a 2.1l if the switch doesn't close the engine won't idle down
properly, it will sit above 1000 rpm and hunt.  Not certain what will
happen if it doesn't open - on the 2.1l the decel shutdown doesn't go
into effect until the engine has been above 2500 rpm and by that
speed with the throttle open I'm not sure what the ECU would make of
the situation.

The reason so many are found to be not working properly is that the
usual failure condition, failure to close, doesn't cause dramatic
symptoms.  It's not a progressive failure, at any given moment it's
either working or it's not.

Yours,
David