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High Lambda Reading V6

I am using a 3.0 V6 engine from a 2002 166 in a kit car, the original car was 2002 CF3.

I previously posted a question regarding post cat Lambda's, thanks for the replies, I have since had bosses welded into the exhaust for the additional probes.

Set up now is:
156 manifold- pre cat lambda (about 3" from manifold)- 200 cell sports cat in silencer- post cat lambda after silencer. Separate pipes for each bank.

Induction side is as it was in the 166 apart from the addition of a K and N filter.

I'm getting high (lean) Lambda readings on the emission test, too high to pass an MOT:
CO is 0.2 Lambda is 1.044. Very similar on both banks.

Ive checked for air leaks around the throttle body and plenum and cant see anything obvious.

Last week I fitted 2 new Bosch pre Lambdas without any difference. Everything seams to be running as it should, start easily enough, gets to temperature, fans cutting in/out etc.

Ive plugged in diagnostic and get the following error codes:

P0433- EVAP circuit.
I don't have EVAP control valve fitted

P0650 - MIL Circuit
Indicator light error. I don't have indicator light connected

U1706- CAN Network (NCM NFR)
Error in communication with ABS. I don't have ABS unit fitted

P1314 Vertical accelerometer/Uneven road surface
From what I can tell this is a sensor in the 166 to do with the car driving erratically.

If I clear the codes disconnect the diagnostic/reconnect the diagnostic same 4 re-appear without starting the car so not errors triggered by running the engine.

Apologies for the long post but need to get the emissions to MOT level so I can register the car and am a bit stuck as what to do?

Thanks
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rxe
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Lambda >1 suggests lean. So you have too much air going into the engine. Lambda at the tail pipe doesn't care where the fuel is burnt - cat or cylinder, its all the same.

CO of 0.2 suggests rich. All that "extra air" should be turning that to CO2

You don't mention the HCs - are they anything other than normal?

Are you sure the cats are actually lighting up? If they are not, you can be throwing unburnt fuel down the exhausts, this will show up as HCs. My 155 does similar if I take it for an MOT without giving it a good thrashing first.

Not burning fuel is the same thing as too much air from a lambda POV.
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(Post Link) post #3 of 5 Old 26-01-17 Thread Starter
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Thanks for the reply.

The HC was very low, I don't have the print out with me at the moment but I think the reading was in the teens.

The car was hot, during the test, they check speedo calibration on the rollers which involves running the car up to around 60/70 MPH, the calibration was out so we did this a couple of times.

The emissions test was repeated probably 4 times on each bank and each time the CO came down until it settled at 0.2 which I assume is the cats warming up.
Until the car is registered I cant drive it on the road to get the exhaust really hot, during the test the fans were cutting in and out, suggesting the car was up to temp.


The guy doing the test also commented high CO indicates a rich mixture and high lambda indicates lean.

This being a CF3 engine the original Alfa had cats in the manifold and in the exhaust, Im now only running cats in the exhaust and am wondering if the high readings are down to the way the ECU is mapped?
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rxe
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You should be able to remove the manifold cats with no problems - loads of people do this on 3.2s as they apparently cook the head gaskets. As long as the lambdas stay in place, the ECU will never know.

I'm pretty certain you are not achieving cat ignition. High CO should be burnt off in the cat - that's the whole point. You are reading lean on lambda because you are chucking out O2 that should be CO2. This is not about engine temperature - the 155 I mentioned earlier can be boiling hot, fans on, and still fail if it has just been idled up to temperature. 300 yard thrash round the nearest roundabout, and it is spot on. Have a chat with the manufacturer - they may be able to give you a surface temperature that shows ignition.

How far are your cats away from the engine? If further than standard it will make it even harder to light up. IMO you're going to need to find and MOT place on an industrial estate where you can give it a few hard runs up and down the road.
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Had 3.0V6 from 166 in kit car(locost) as well.....
Why don't you get rid of CF3 ECU and wires, and fit less "lambdable" CF2 ecu and loom.....passing CO emission will be easy as well.....
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