Evening all,

Today my father in law took my old (now his) BMW Z3 for it's MOT test and it failed on a few things, mostly easy fixes but 1 may not be, the emissions are above the limit and therefore I don't know if it would need a new cat or lambda, however, my very astute wife noticed that the vehicle quoted at the top of the emissions test report is the right reg no but the wrong type, model and engine. It shows as an X5 (E70) 3.0si instead of the Z3 1.9. Does anyone know if these readings are linked to the model and type and therefore could have showed a failure thinking it was a test for a more modern car? I've uploaded a picture and would be grategul if anyone could help.





If this is not the case and the car does need the emissions sorting besides the usual service (oil, plugs and filters) would it be a good idea to replace the cat which is of unknown age and looks a bit ropey? I also was thinking would it be of benefit for me to use my obd interface to look at the live data to see what the oxygen sensors are and maybe aim for a better reading after the service? Does anyone know what the readings should be so I know what to aim for? I only get 1 retest free so would like to sort it in one go.

Cheers.

Those are specific limits for that listed vehicle. Whether the actual cars limits are different I can't say. If it was all running correctly then it should meet them though.
What were the fail results?

The actual values for the test are blank on the test sheet so I don't know

Never not been given the test results and thought they had to supply a copy. Without them it's difficult to find the solution. I'd go back and point out the error and ask for the test to be redone and get them to supply the result.

Ditto - would get the results from the garage so you can do some diagnostics.

If it's high hydrocarbons it may be something as simple as a hole in the exhaust...

100% agree without the test results you wlll have a hard job finding the cause of the problem, 9 times out of 10 the cause is something simple.

On the plus side DIY plug-in diagnostics for BMWs are easily available --- although it may need a BMW adapter lead if the socket is not a standard 16 pin OBD socket. Dedicated BMW diagnostic software tools are available quite cheaply on ebay but a cheap standard ODB USB adaptor or a scanner that shows live live data will let you look at the various sensor output and let you see if the lambda is "switching" at sufficiently fast rate.

If the car is over 10 years old the Lambda sensor will probably be getting a bit lazyand a new sensor would be beneficial but don't start changing parts at random it is a lottery one seldom wins.

take it on the motorway in 3rd and hammer it for 20 miles with no air filter in. then put it through withno air filter in car it will pass no worries.

My 5 series is on 195k miles and i failed 2 years ago on emmisions and the MOT guy took my filter out and left it running at 5000 rpm's for 20 mins. passed no worries.

hope this helps.

It looks like the lambda sensor is duff. I plugged my obd interface into the car this morning and although the car does not have a mil lamp on the dash there was a dtc code stored in the memory P0130 and when I veiwed the live data the oxygen sensor never moved from 0.435V . So fingers crossed should be an easy fix.