Lambda B problems caused by air leak ?
Discussion
Finally connected up my Ecumate today. What an amazing piece of kit. I was worried about my running temps but was able to see the thermostat open at 82 deg, then the fans kick in at 92. Dash guage would have me believe the engine temp was about 70 deg.
The engine has been a bit rough lately especially at idle, I know why now - Lambda B is all over the shop. While Lambda A sits at OK Lambda B goes rich, lean ok, fault, rich ok rich ok lean fault lean ok lean fault etc.
Looking under the bonnet I can see some soot stains under the clamp from the exhaust manifold to the Y piece, I assume air is getting in and confusing the lambda sensor, does this sound right ?
The engine has been a bit rough lately especially at idle, I know why now - Lambda B is all over the shop. While Lambda A sits at OK Lambda B goes rich, lean ok, fault, rich ok rich ok lean fault lean ok lean fault etc.
Looking under the bonnet I can see some soot stains under the clamp from the exhaust manifold to the Y piece, I assume air is getting in and confusing the lambda sensor, does this sound right ?
Yep sounds about right!
I'd get some exhaust paste and slacken off and retighten the offending clamp with plenty of the aforementioned first. If its still playing up then you could replace the sensor. They can go faulty but it's also possible that the wiring to it might be perished. A continuity test from ecu to lambda plug might be worth doing as well as the sensors aren't cheap (£50 ish)
I'd get some exhaust paste and slacken off and retighten the offending clamp with plenty of the aforementioned first. If its still playing up then you could replace the sensor. They can go faulty but it's also possible that the wiring to it might be perished. A continuity test from ecu to lambda plug might be worth doing as well as the sensors aren't cheap (£50 ish)
Normally it will go rich or lean (+ or - 255) if there is a constant fueling error or air leak. Its possible you have a misfire, as this will give a lean reading to the ECU, so it chucks in extra fuel and if the mixture then fires intermittently it will be too rich, so it backs the fueling off again. I cant think of any other reasons to swing back and forth between extremes. Its quite normal to see the odd blip of rich or lean, its just the ECU has not trimmed the mixture quite far enough.
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