94 SPi - running a bit rich

What's the most popular sensor to fail which would cause the ECU to run the
engine at about 500rpm with the odd whiff of black smoke and lots of unburnt
petrol out of the exhaust?

erik.

Normally this would be the lambda sensor in the exhaust downpipes. Make sure
the ehxaust doesn't blow anywhere aswell tho. Does the choke work ok from
cold. It should go to around 1100rpm ish if I remember rightly from cold
then settle at 850. You dont say what yours idles at on cold start.

Chris

"erik fishead" <erikfishead (AT) oddfellow (DOT) co.uk> wrote

What's the most popular sensor to fail which would cause the ECU to run
the engine at about 500rpm with the odd whiff of black smoke and lots of
unburnt petrol out of the exhaust?

erik.

On Wed, 07 Dec 2005 01:13:06 GMT, "erik fishead"
<erikfishead (AT) oddfellow (DOT) co.uk> wrote:

What's the most popular sensor to fail which would cause the ECU to run the
engine at about 500rpm with the odd whiff of black smoke and lots of unburnt
petrol out of the exhaust?

erik.

Are you sure it's not a good old-fashioned misfire? What's the
performance like otherwise?

Cheers,

Colin.

Normally this would be the lambda sensor in the exhaust downpipes.

Lambda confirmed as OK in this afternoon's fault code test, as did the rest
of the sensors. Turned out to be a split pipe boot on between the back of
the inlet manifold and the fuel trap which goes to the Manifold Absolute
Pressure sensor in the ECU.

Quick trip to the scrappies to take a look at some SPi Metros resulted in a
couple of spare boots; one for now, one for next time.

erik.

Are you sure it's not a good old-fashioned misfire?

Pretty sure. Started fine and ran beautifully when cold, as it warmed up the
idle speed was getting lower and lower until it bottomed out at about
500rpm. No hunting, just plenty of unburnt fuel and black smoke.

What's the
performance like otherwise?

Before it came off the road in May, fine except for a lack of power but no
misfire around 3500rpm. No MOT at present, so only able to take it up and
down the drive. Wheelspins in 2nd once warmed up though.

As previous post, now resolved.

erik.