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Author Topic: MOT fail emissions update  (Read 2333 times)

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pigtown

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MOT fail emissions update
« on: 19 February 2011, 11:33:59 »
Continued from a previous thread...

Changed both Lambda sensors and still fails.
The lambda reading was consistently 1.13 (pass is .97 to 1.03).
They also tried the test on LPG and it failed on HC level.

The pre cat sensor isn't standard wiring presumably due to the LPG - although the same set up has passed in previous years. I will tidy up the wiring and check the joints are ok.

Anything else worth trying?  MAF?
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Entwood

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Re: MOT fail emissions update
« Reply #1 on: 19 February 2011, 11:38:58 »
Rather than throw money at it I'd be inclined to take a drive to either TB or KW and have a PROPER tech2 session with "someone who knows" .. the block learns and live readings on a proper bit of kit may well pinpoint the problem within minutes .. whilst changing bits for the sake of it is "hit and miss"

Having typed that .. then realised you have no MOT so can't get it to them .. :( I wonder if theres any other way of getting a proper reader on it as mine is obviously not sophisticated enough.. :(
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Lazydocker

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Re: MOT fail emissions update
« Reply #2 on: 19 February 2011, 13:55:08 »
Quote
Continued from a previous thread...

Changed both Lambda sensors and still fails.
The lambda reading was consistently 1.13 (pass is .97 to 1.03).
They also tried the test on LPG and it failed on HC level.

The pre cat sensor isn't standard wiring presumably due to the LPG - although the same set up has passed in previous years. I will tidy up the wiring and check the joints are ok.

Anything else worth trying?  MAF?

Really? The correct LPG test is very basic and the HC level is 1200ppm :o :o
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pigtown

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Re: MOT fail emissions update
« Reply #3 on: 19 February 2011, 15:42:54 »
My mistake it was the CO level that failed it was 9.06% the limit is 3.5%.
the HC was pretty high though at 1119ppm.
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Lazydocker

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Re: MOT fail emissions update
« Reply #4 on: 19 February 2011, 18:14:12 »
Ahhh.... That's really not right then :(

What system do you have on it?

But, as the petrol is way out too you really need to get a proper Tech2 on it.

I assume you've done all the normal things like full service etc?
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pigtown

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Re: MOT fail emissions update
« Reply #5 on: 19 February 2011, 19:29:08 »
It's a mixer system so quite basic.
Not serviced it recently. Plugs are about a year old. As it's running weak the air filter must be ok? What else do you suggest?
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Lazydocker

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Re: MOT fail emissions update
« Reply #6 on: 19 February 2011, 20:20:21 »
Quote
It's a mixer system so quite basic.
Not serviced it recently. Plugs are about a year old. As it's running weak the air filter must be ok? What else do you suggest?

Ahhh... That's unlikely to ever pass an MOT test on LPG then... Not best suited to the car and, unfortunately, it may have knackered the cats :(

BUT... That's not a definite answer, just a possible ;)

I would suggest a good service to start with, followed by an "Italian Tune Up" ::) ::) Might be worth bunging some injector cleaner through too :-/ I change my plugs Annually now I'm on LPG, although that may be a little OTT for my setup. Mixer systems are very crude and it sounds like they're using the wrong Lambda sensor for the Leonardo control unit (assuming you have one) if it's wired to the pre-cat sensor :-/ Unfortunately I's nigh on impossible to diagnose without seeing it
« Last Edit: 19 February 2011, 20:21:41 by Lazydocker »
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pigtown

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Re: MOT fail emissions update
« Reply #7 on: 19 February 2011, 21:35:26 »
The pre cat sensor is connected to the ECU. When I replaced it I had to cut and connect following the original wiring.
It actually runs better on LPG than petrol. On start up it runs a bit rough on petrol.
What happens in an Italian tune up?
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Entwood

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Re: MOT fail emissions update
« Reply #8 on: 19 February 2011, 21:47:40 »
Quote
The pre cat sensor is connected to the ECU. When I replaced it I had to cut and connect following the original wiring.
It actually runs better on LPG than petrol. On start up it runs a bit rough on petrol.
What happens in an Italian tune up?


you keep one eye on the mirror looking for Mr Plod !!  :)

Italian tune up is driving it hard .. up to rev limiter in the gears quite a few times .. drive it like you stole it .. it has a tendency to clean out any crud from the intake/exhaust/valves and plugs (as well as your wallet) !!

WARNING : has a tendency to become a habit as it comes under the heading FUN !!!  ....  but don't do it in the wet !!

:)
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Lazydocker

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Re: MOT fail emissions update
« Reply #9 on: 19 February 2011, 21:50:04 »
Quote
WARNING : has a tendency to become a habit as it comes under the heading FUN !!!  ....  but don't do it in the wet !!

:)

Especially when you realise that the fuel is reasonably cheap being LPG :-X ::)

Although, that may be why I'm unsure about the work done today... Was driving quite hard and it's very wet ::) ::)
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pigtown

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Re: MOT fail emissions update
« Reply #10 on: 20 February 2011, 15:08:19 »
Tidied up the sensor wiring today and checked the plugs. They all look good which suprised me if it has been running weak.
I also tried running without the MAF connected and it didn't make much difference - if anything it revved cleaner from tickover. Would the MAF affect the lambda readings?  I'll try the Italian tune up but will have to be double careful as the MOT has expired!!
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pigtown

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Re: MOT fail emissions update
« Reply #11 on: 21 February 2011, 13:22:52 »
Italian Tune up complete without mishap or involvement by the long arm...

I did notice the exhaust now at tickover is clear where as previously there was some smoke. When the last test was done there was smoke during the whole test so maybe it hadn't warmed up enough??

With no other path to go down I'm going to get a new MAF and try a retest later in the week.
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Julian James

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Re: MOT fail emissions update
« Reply #12 on: 21 February 2011, 15:15:51 »
I believe you're allowed to drive a car without an MOT if you are going to or from the place where it is being fixed.  This could include a diagnostics session ;)

Prob is fine to do that, especially if you don't mind ragging it around anyway without an MOT!
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Kevin Wood

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Re: MOT fail emissions update
« Reply #13 on: 21 February 2011, 17:21:59 »
Quote
I believe you're allowed to drive a car without an MOT if you are going to or from the place where it is being fixed.  This could include a diagnostics session ;)

Prob is fine to do that, especially if you don't mind ragging it around anyway without an MOT!

It would need to be pre-booked, and I'm guessing it'd need to be a business that the plod can call on and confirm the booking if you did get a tug.

Kevin
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TheBoy

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Re: MOT fail emissions update
« Reply #14 on: 21 February 2011, 17:47:55 »
Replacing parts on a hunch will only cost money, and wont resolve the issue.
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