leaking exhaust joint & lambda readings

[Seight-v8]

hello al,

What effect would a leaking exhaust joints make on any lambda readings, if the 4-1 joint was leaking and the lambda sensor was only about 4ins from the joint?....

cheers

scott

[rob@vems.co.uk]

Depends if the sensor is up or down stream from the exhaust I guess.

[Seight-v8]

its downstream about 4ins from a 4-1 joint, and i am just wondering if it might be drawing in air....which may be giving my lambda sensor false readings.....

i've been getting lambda 1.00 readings on my netbook but my MOT station is getting 0.94 readings....

if its drawing air....maybe this leans the readings, then vems puts in more fuel....so i end up with rich readings...

if this makes any sense....

scott

[MWfire]

if draw air, thain lambda readings are leaner.

[Seight-v8]

cheers think this might not be helping my lambda readings, ran the car yesterday and exhaust gas is leaking from 2 pipes on my 4-1 joint.

So took it off this morning and some of the pipes are quite loose in the fit, so i am off to find a local place to expand the exhaust pipes to match the 4-1 joint.

scott

[Sprocket]

a leak before the lambda sensor will artificially read leaner than it actually is, IE the fueling is actually rich, but the extra oxygen makes the ECU think it is not (low lambda at the tail pipe). A leak after the sensor will not affect the fueling of the engine, but will make the tail pipe readings leaner (high lambda at the tail pipe)