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General >> Problems >> MOT passed but.....
(Message started by: Nunnspoet on Apr 27th, 2010, 8:45am)

Title: MOT passed but.....
Post by Nunnspoet on Apr 27th, 2010, 8:45am
... not quite estatic as she only just passed.

What do you think?

Fast Idle Test:

RPM   Min limit    Max limit    Actual Value
          2500        3000          2718

CO    Max limit    Actual Value
          0.200        0.101

HC       200           19

Lambda   Min limit   Max limit    Actual Value
                  0.970      1.030        1.001


Natural Idle Test:

RPM    Min Limit    Max Limit    Actual Value
            450            1500          709

CO     ...........         0.3000        0.299


Am I right in saying that she only just passed?  Aaaannnndddd am I right in suspecting one of the Oxygen sensors, folks?

Mike


Title: Re: MOT passed but.....
Post by Nunnspoet on Apr 27th, 2010, 8:48am
Sorry but the text has slipped across and the Values are not under the Titles.  They have slipped to the left but I think you will be able to follow it ok.

Mike

Title: Re: MOT passed but.....
Post by martin_rowe on Apr 27th, 2010, 10:28am
looks fine dont worry.

Title: Re: MOT passed but.....
Post by Nunnspoet on Apr 27th, 2010, 3:34pm
:) Ta very much Martin

Title: Re: MOT passed but.....
Post by tlundkvi on Apr 27th, 2010, 5:13pm
Is that just wandering figures, or did you have an idle CO of 0.299 when 0.3 is allowed? If the lambda is 1.001 the lambda sensors are IMHO in order, shouldn't the system otherwise mess it up? What model is it and do you know if the cat is original?

Title: Re: MOT passed but.....
Post by Nunnspoet on Apr 28th, 2010, 8:35am
Thanks tlundkvi.  Yes, CO reading 0.299 when 0.3 allowed.  This is why I am concerned about the MOT result.  She is a 1996 2.9 V6 Scorpio Cosworth Ultima Estate with 143,000 miles on the clock.  EricR replaced the nearside Cat about 5?years ago but I don't know about the offside Cat.  It looks pretty old.  

The Fast Idle Test CO figures of 0.200 Max Limit with an Acutual Value of 0.101 may in comparison to the Natural Idle result, mean something to you or indeed somebody else.  

I am in possesion of an OBD lead at present but am still learning how to get the best out of it.  I did a read-out just prior to the MOT, clearing the Codes which showed the 2 post Cat sensors as useless and reported a fault ERG.  The post Cat sensors don't matter and because the EGR fitment to the Exhaust was loose and I was/am broke and could not afford to get it welded I removed EGR completely blocking the 2 orifices with 2x1 pennies.  Hence "The Beast" is now refered to as "Tuppence" so that explains the Fault Codes.

Mike      
 

Title: Re: MOT passed but.....
Post by amigafan2003 on Apr 28th, 2010, 3:18pm
The catalyst probably wasn't very hot.  I bet a spirited drive round the block would have bought the CO reading right down.

Really, there is nothing wrong with those figures at all.  I've noticed during my supervision of MOT's that 50% of them fail on the idle test initialy - a quick drive round the block gets 99% of them through.


Quote:
clearing the Codes which showed the 2 post Cat sensors as


We're they totally out of spec or reading rich?  Rich post cat means the cats are failing (or not hot enough as I have aluded to already).

Title: Re: MOT passed but.....
Post by Mike H on Apr 28th, 2010, 7:47pm
I have more than once had the EGR valve taken off and cleaned to ensure it gets through the emissions. It's left to soak in something overnight, can't remember what offhand

Title: Re: MOT passed but.....
Post by tlundkvi on Apr 28th, 2010, 8:16pm

on 04/28/10 at 08:35:29, Nunnspoet wrote:
Thanks tlundkvi.  Yes, CO reading 0.299 when 0.3 allowed.  This is why I am concerned about the MOT result.  She is a 1996 2.9 V6 Scorpio Cosworth Ultima Estate with 143,000 miles on the clock.  EricR replaced the nearside Cat about 5?years ago but I don't know about the offside Cat.  It looks pretty old.  
 


Mine failed on me in winter 2008 on a -95 cossie, so they can fail. I would recommend exhaust testing 2 months or so before next MOT. But you apparently have a year to prepare yourself. I tried vacuum leaks, sensor switches, 2x forte, driving 80km/h in 2nd etc. Luckily one cat is quite cheap from buypartsby.

Title: Re: MOT passed but.....
Post by Nunnspoet on Apr 29th, 2010, 7:33am
:).  Thanks everybody for your input and advice.  I really apreciate it.

Mike    ;)    

Title: Re: MOT passed but.....
Post by Mike H on Apr 29th, 2010, 12:51pm
It's quite feasible the EGR functions at idle and fast idle for the test (no 'load' as such on the motor, so not much fuel / air needed), but because you took it off it's not being diluted by recycled exhaust gas, hence the high numbers. Just a guess. It's the only explanation I can think of that matches my own experiences.

That is to say, first emission test, it's a bit high, or even too high, clean the EGR, it's better. (?)

Title: Re: MOT passed but.....
Post by Nunnspoet on May 4th, 2010, 10:24am
I'm a bit poorley at the moment, but I'll be back.

Mike    

Title: Re: MOT passed but.....
Post by Mike H on May 4th, 2010, 12:30pm
Sorry about that, hope you recover soon!

Title: Re: MOT passed but.....
Post by Nunnspoet on May 8th, 2010, 5:54pm
Ta very much

Mike   :)

Title: Re: MOT passed but.....
Post by Albert_Ross on May 9th, 2010, 7:39am
My thoughts on this one... (I am a class 4 MOT Tester) The natural idle test was carried out too soon after the fast idle test, not given about 30 seconds between the 2. Normally, on an older vehicle with a cat, at higher mileage, recovery time is slightly longer, so I give a bit more time to let the system settle. Everything is probably completely normal, so I shouldn't worry about it.

Title: Re: MOT passed but.....
Post by Nunnspoet on May 9th, 2010, 9:36am
;)  Something to ponder there Albert.  Thanks.

My mind is a lot easier now.

Mike    ;)

Title: Re: MOT passed but.....
Post by Nunnspoet on May 9th, 2010, 9:38am
Smileys should have been :).  Ahh well.

Mike

Title: Re: MOT passed but.....
Post by Mike H on May 9th, 2010, 10:08am

on 05/09/10 at 07:39:17, Albert_Ross wrote:
My thoughts on this one... (I am a class 4 MOT Tester) The natural idle test was carried out too soon after the fast idle test, not given about 30 seconds between the 2. Normally, on an older vehicle with a cat, at higher mileage, recovery time is slightly longer

That makes sense!



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