What does this tell anyone about a 1994 V6 with 110k on the clock.
Fast Idle Test:
CO Max - 0.30% Actual - 0.15%
HC Max - 200ppm Actual - 16ppm
Lambda Range 0.970-1.030 Actual - 1.243 (Fail)
Second Fast Idle Test:
CO Max - 0.30% Actual - 0.11%
HC Max - 200ppm Actual - 10ppm
Lambda Range 0.970-1.030 Actual - 1.185 (Fail)
Natural Idle Test
CO Max - 0.50% Actual - 0.44% (Pass)
Apart from the fact you can tell it failed its MOT, what do these figures suggest? A new pair of Lambda sensors?
Thanks
|
Says to me your motor's in pretty damn good shape for a '94.
Unless you've got mpg or power issues, I'd put in a bottle of Redline SI2 injector detergent (Yank product available from Demon Tweeks £4.45 +post 01978 664466 ) check the air filter's clean, give it a good fast run - not necessarily in that order - then take it back if you're on a free retest.
If not, or they fail it again, try another garage for the MOT. Hope they don't find anything mechanical that the first garage didn't though. :-(
|
|
|
Crombster,
Didn't the tester tell you what was likely to be the problem? I would have thought he would know this from experience.
I happen to have my own test results to hand which might be interesting as a comparison. These were for my 1992 BMW 525 with 114k on the clock ...
Fast Idle Test:
CO Max - 0.30% Actual - 0.01%
HC Max - 200ppm Actual - 15ppm
Lambda Range 0.970-1.030 Actual - 1.008
As you can see, our hydrocarbon readings were almost identical but your carbon monoxide reading was a lot higher and I wonder if this is related to the high Lambda reading. I have no idea if you need new Lambda sensors though; I've never dabbled with those things.
|
Yes use some injection clearer and check the normal service items but it looks as though the LAmbda sensor is away. Goto www.forparts.com/o-21.htm for more information but the management system or LAbda light should have come on.
Peter
|
|
|
|
Crombster
Basically, the engine is fine. Lambda is the correct air/fuel ratio, hence it should be 1.0. The engine electronics keep this ratio correct based upon data from the lambda sensor, and driving the fuelling accordingly.
The deviation on your car indicates that the air fuel/ratio is a little incorrect, confirmed by the slightly high CO reading. You car is running a bit fuel rich, and the CO will drop to virtually zero when it's corrected.
Could need a new lambda sensor or two, but try the can of injector cleaner and an Italian tune up first. The other possibility is oone or more faulty fuel injectors, which are making the car run too rich.
Regards
John S
|
|
Spot on John. I would add my two pen'orth by saying that that time and again the poor old O2 sensor is blamed for a failed Lambda calculation. It may well be contributing to the problem if it is fouled or dirty as would a similarly afflicted fuel injector. The valves may be carbon fouled with the use of poor quality fuel and the catalytic converter may be partially restricted. A dose of Texaco Cleansystem 3 fuel beefed up with a quality fuel injector cleaner and a good fast run will probably sort it before calling in an expert.
|
|
|
|
_COLON_no_upscale()/cdn.uk.prod.group-mobility-trader.com/images/fallback/coming-soon.jpg)
