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Wesley
Trade Member
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Posted: Fri May 28th, 2010 11:31 pm |
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shpauly wrote: usually a leaking exhaust will give a higher lambda reading?
well, maybye its not switching correctly and maybye its fcuk-ed! ??..
a "live data" or "scope" session will prove its correct operation. 
A Much better direction of diagnosis rather than your original option, of a "talking crystal ball" that, ass.u.me.`s "the cat"!
the procees of catalysation produces "heat"?, so one end of the "cat" will be hotter than the other?!
Go Figure!
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shpauly
Member
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Posted: Fri May 28th, 2010 09:09 pm |
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| usually a leaking exhaust will give a higher lambda reading
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Wesley
Trade Member
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Posted: Mon May 24th, 2010 10:11 pm |
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Hi,
If the lambda reading is low, 0.964, then the ecu will provide more fuel to compensate, 1.22%. a blowing exhaust can affect the lambda sensor readings.
A Diagnostic "Live Data" session should help you sort it.
Wes.
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shpauly
Member
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Posted: Mon May 24th, 2010 09:01 pm |
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burns76 wrote: Presented my 2002 Audi TT [225] Quattro for MOT and was failed on emissions at fast idle; it passed at natural idle. Now I'm a little confused as the printout says that the RPM wasn't checked at either fast or natural idle. I watched the mechanic put a sort of block thing on the pedal to keep it at fast idle - should it not be a bit more scientific than that?
Anyway, my results are as follows:
CO: 1.22% Fail
HC: 73ppm Pass
Lambda: 0.964 Fail
Three questions:
My car is on a private plate which begins with a T. If the tester didn't know the true year of registration (he didn't ask) would this affect the test he performed on emissions? ie, if he thought it was a true T-reg rather than a 2002 model?
In December I had a replacement pre-cat Lambda sensor fitted, and a matter of hours before the MOT test, had a new post-cat Lambda sensor fitted. What else can be wrong?
The test parameters are different between this MOT test and a previous one I have for my car. ie the engine speed for fast idle on this test is shown as 2450-2850, whereas a previous one was 2500-3000. How come?
Sorry for the long post, but I just don't understand! Going in to my usual garage tomorrow for it to be popped on the diagnostic (they don't do MOTs otherwise I'd have had them do it), but there are no warning lights on the dashboard so I can't imagine what fault codes we might get or how to get this sorted.
Thanks for any and all replies.
sounds like your catalytic converters possibly faulty,engine speed not usually measured as normally no access to plug leads on modern engines without stripping covers and on yours coils will be fitted with no leads.2002 model will still fail on this as 0.3% is maximum.
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kev1975
Trade Member
| Joined: | Wed Sep 5th, 2007 |
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| Posts: | 755 |
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Posted: Mon May 24th, 2010 08:58 pm |
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burns76 wrote:
Presented my 2002 Audi TT [225] Quattro for MOT and was failed on emissions at fast idle; it passed at natural idle. Now I'm a little confused as the printout says that the RPM wasn't checked at either fast or natural idle. I watched the mechanic put a sort of block thing on the pedal to keep it at fast idle - should it not be a bit more scientific than that?
Anyway, my results are as follows:
CO: 1.22% Fail
HC: 73ppm Pass
Lambda: 0.964 Fail
Three questions:
My car is on a private plate which begins with a T. If the tester didn't know the true year of registration (he didn't ask) would this affect the test he performed on emissions? ie, if he thought it was a true T-reg rather than a 2002 model?
In December I had a replacement pre-cat Lambda sensor fitted, and a matter of hours before the MOT test, had a new post-cat Lambda sensor fitted. What else can be wrong?
The test parameters are different between this MOT test and a previous one I have for my car. ie the engine speed for fast idle on this test is shown as 2450-2850, whereas a previous one was 2500-3000. How come?
Sorry for the long post, but I just don't understand! Going in to my usual garage tomorrow for it to be popped on the diagnostic (they don't do MOTs otherwise I'd have had them do it), but there are no warning lights on the dashboard so I can't imagine what fault codes we might get or how to get this sorted.
Thanks for any and all replies.
engine speed does not need to be measured on the machine & sometimes cannot be measured accurately on some vehicles , bit of stick to keep it at a steady speed & use the rev counter in the car is acceptable .
the reason the engine speeds appear different between the 2 tests is that the last year mot must have passed on the basic emission test , this years has been a vehicle specific test , hence the revs being specified differently .
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burns76
Member
| Joined: | Sun May 23rd, 2010 |
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Posted: Sun May 23rd, 2010 11:58 pm |
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Presented my 2002 Audi TT [225] Quattro for MOT and was failed on emissions at fast idle; it passed at natural idle. Now I'm a little confused as the printout says that the RPM wasn't checked at either fast or natural idle. I watched the mechanic put a sort of block thing on the pedal to keep it at fast idle - should it not be a bit more scientific than that?
Anyway, my results are as follows:
CO: 1.22% Fail
HC: 73ppm Pass
Lambda: 0.964 Fail
Three questions:
My car is on a private plate which begins with a T. If the tester didn't know the true year of registration (he didn't ask) would this affect the test he performed on emissions? ie, if he thought it was a true T-reg rather than a 2002 model?
In December I had a replacement pre-cat Lambda sensor fitted, and a matter of hours before the MOT test, had a new post-cat Lambda sensor fitted. What else can be wrong?
The test parameters are different between this MOT test and a previous one I have for my car. ie the engine speed for fast idle on this test is shown as 2450-2850, whereas a previous one was 2500-3000. How come?
Sorry for the long post, but I just don't understand! Going in to my usual garage tomorrow for it to be popped on the diagnostic (they don't do MOTs otherwise I'd have had them do it), but there are no warning lights on the dashboard so I can't imagine what fault codes we might get or how to get this sorted.
Thanks for any and all replies.
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