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MOT Failure - Emmissions

rajagger

rajagger

New member
My 944 Lux has failed its mot on the emmissions.

The garage have tried to adjust things but are not getting low enough to get a pass.

The first thing that came to my mind was the Air Flow Meter.

I was thinking of trying get hold of a used part. Anyone got a spare one?

Is there anything else that I could try first, before I get another AFM?

Cheers

Richard
 
Does your Lux have an O2 sensor?? from Clarkes garage http://www.clarks-garage.com/index.htm
"
For 944s which are equipped with oxygen sensors (not all are), the O2 sensor measures the oxygen content in the exhaust and provides an output feedback signal so the DME will know if the mixture is too rich or too lean. The DME then adjusts the amount of fuel to correct the mixture. The O2 sensor is also known as a Lambda sensor.
When the DME is operating based on the feedback signal from the O2 sensor, this is referred to as Closed Loop operation. If the O2 sensor is faulty or is disconnected, the DME computer operates in Open Loop mode. In this case, the DME simply proves the fuel by determining the amount of air flow into the engine and selecting the appropriate amount of fuel from a set of preset fuel maps. On 944s which do not have O2 sensors (many ROW cars), the DME operates in Open Loop mode from preset fuel maps. "

"
Symptoms of a Bad O2 Sensor
The following are some of the symptoms you might see if your O2 sensor is failing or has already failed:

  • Engine surges or hesitates
  • Strong smell of gas from the exhaust
  • Poor fuel economy
  • Failed emissions due to high CO or high HC levels
  • Catalytic converter (if equipped) becomes prematurely clogged "
They go on to show how to test your O2 (Lambda) sensor.
 
Agreed, very interesting. I have always thought that my S2 smells very fumey, especially noticeable as I reverse it into its garage. I will try and check this out along with the all the other little jobs that are occuring.
 
Doubt an 87 Lux has an O2 sensor. Have you been using the car recently?
If not might help to put a tank of new fuel and some injector cleaner in, and give it a thrash. Then run for half an hour or so before the MOT so the engine is properly warmed up when you get there.
If not, the MAF meter is pretty simple and you can run some basic voltage checks on it. Porsche 944 manual from www.cannell.co.uk will tell you what to do.
 
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