lambda reading

[tomwest]

My lambda was tested in its recent MOT. the results are causing me problems.

we have the following:

1st test - limit allowed - actual values - results
engine RPM: - 2450/3050 - manual check - pass
CO % VOL - 0.20 - 0.00 - pass
HC ppm VOL - 200 - 18 - pass
lambda - 0.97 to 1.03 - 1.98 - fail

2nd test
engine rpm - 2450/3050 - manual check - pass
CO % VOL - 0.20 - 0.00 - pass
HC ppm VOL - 200 - 28 - pass
lambda - 0.97 to 1.03- 2.04 - fail

natural idle test
CO % VOL - 0.30 - 0.00 - pass


what is the lambda test, and why, when my CO and HC levels are so low, is it double its specified limit........ its such a confusion.

more to the point, what is the failed point in the system. during the test i had no back box and no air filter. fuel pressure standard with 2.2mm gap bosch super 4s.

 

[frank]

Faulty equipment maybe ?

 

[tomwest]

thats what i was thinking..... theres no way it could be reading so far out when the other two are close and related.

 

[frank]

A co of zero and lambda of two does,nt sound right eh tom

 

[tomwest]

yeah exactly my thoughts. however...... is it possible they were using a "stick it in the end" type sensor? if this is the case, the problem may be the little end tip i had on the exhaust. its a typical halfrauds jobbie and isn't a seal around the actual exhaust. if they didnt stick the end of the sensor in far enough, could it pick up on the "loose" air being taken in through the gap?