car not running properly

[mainsy]

my s1 all of a sudden lost power and wouldn't idle, and it was blowing out black smoke and a kind of sulpher smell coming from the exhaust. i pulled over and switched off and tried to turn on again but the car would'nt start.

after a few phone calls i was advised to pull out a plug which is the throttle position sensor, but i'm quite clueless so i didn't know what that was so i pulled out this one and it started and i was able to drive home, surprisingly normally.



any ideas what the problem is and what part will i need to rectify?

thanks in advance

[tut]

You can get corrosion in the TPS especially in early cars. Try unbolting it and give it a good clean. Before that try connecting it again and give it a light tap with a screwdriver.

If neither of those work, sit back and wait for Robin.

tut

[mainsy]

cheers for the advice tut your always quick to answer my distress calls

my neighbour had a look and thinks the plug i had unplugged looked more like an airflow sensor

[mwmackenzie]

That's the IVAC you've unplugged, the TPS is to the left of that in the throttle body! If your getting black reek out the back it sounds like your over fueling which would be the TPS maybe if the IVAC is stuck open while disconnected it would weaken the mixture allowing the car to run but not right?? All speculation on my part here but hope it helps so in short I think TPS? Try giving Ali a call 07961445483 he should know what's up.

Good luck

Mark

[robin]

What happens if you reconnect the IACV - does it stop idling again?

Lost all power and belching out black smoke sounds like over fuelling - either because your air intake is blocked, or because the lambda sensor is faulty (though this latter would have no effect at full throttle or during the warm up phase, so if it's only a problem on steady throttle, once warmed up, lambda sensor is quite likely).

Could also be a collapsed cat causing excessive back pressure and thus making the engine run rich ...

Cheers,
Robin

[mainsy]

i never plugged it back in so don't know if it would still idle, will give it a go tomorrow, but as soon as i unplugged it she started and ran no bother, but i just limped home to be safe.
i phoned ali and his initial thought was the TPS but unplugging that didn't change things.
so is the bit i put the plug into the part that will need replaced? if that is the problem?

[robin]

Might be - might just need cleaning - but I don't understand why it would have any effect at all on running under load - it's used for controlling the amount of air that the engine needs to idle - when you open the throttle, the ECU closes the IACV (apart from certain circumstances). I agree with ali that TPS is much more likely - I wonder if there is a dodgy wire in the connector and you disturbed it whilst unplugging the IACV and thus fixed it.

Cheers,
Robin

[mainsy]

took the car out this morning and it is running as normal. plugged it back in and started first time, i took it very easy on warmup, then after about 20 mins i gave the car a good run and all seemed well. covered about 40 miles and no problems. strange, but i feel uneasy because its always at the back of the mind something is going to pack in.

i'm hoping to be doing kames on thursday night so it was just a little glitch that won't come back

[Matelotman]

but i feel uneasy because its always at the back of the mind something is going to pack in.

Doesn't every Elise owner have that feeling?