Co2 failure after lay-up

[Chipstick]

Hi, new to the forums so I hope I am posting in the correct place.

I bought a Z4M but after less than a 1000 miles had to store it for 18 months due to illness. When I took it out it failed the CO2 at idle on the MOT. Permitted is 200 and it was 1,800. I filled up the half full tank with Tesco momentum and ran the engine at medium revs for about 15 minutes (it's had a rebuilt engine and is not fully run in yet) - The MOT centre then tested it twice - 1100 and 5 minutes later to 800. Their diagnostics said 2 of the oxygen sensors were not connected but they are (they were switched around with good ones so it's not the sensors).
Any idea how I could rectify this? I just want to drive my beloved beast but it's depressing me instead. I can't take it to specialist because I can't tax it because it has no MOT.

thanks for any pointers, Jim

[ph001]

Need INPA or ISTA to look at lambda sensor voltages. Thankfully that can do done on your drive!

[Rockhopper]

Its CO rather than CO2. (carbon monoxide rather than carbon dioxide). CO2 is tested as part of the homologation process but not at MOT time.
CO readings at MOT are usually given as a percentage, so 0.04% Hydrocarbons (HC) would give the kind of figures you are quoting with a pass at 200ppm. HC is basically un-burnt fuel (or oil) in the exhaust.

So, change the oil, then take it for a good run to get the CAT nice and hot and then get it tested ASAP (high HC can also indicate a failed or failing CAT).

[Chipstick]

Hi, thank you for the rapid responses.

I can change the oil (though it has done less than 1000miles) but can't take the car for a good run as it has no MOT or tax.

Can you tell me what INPA or ISTA are?

thanks, Jim

[Rockhopper]

You can book it in for an MOT then take it for a run to the Mot centre - nothing about must take the shortest route in the law

[Z4paul]

Assuming you can change the oil as above then you shiuld be able to get it tested xand hopefully pass the rest following the suggestions given. This from the RAC suggests you would be entitled to drive to the test-
'If you’re taking your car to a pre-booked MOT test, you can drive your vehicle on a road without it being taxed. The law doesn’t state how far you can travel, but if you stop off at the shops on the way or cover an unreasonably long distance it could be deemed that you’re using the vehicle for other purposes and the exemption won’t apply'

[Z4paul]

You can book it in for an MOT then take it for a run to the Mot centre - nothing about must take the shortest route in the law

Snap !!

[enuff_zed]

So if you wanted to be better covered if stopped, you could email the garage to pre-book the appointment, explain the advice you've been given ref the longer run, and ask them to respond in agreement.
Not exactly a water-tight case m'lud, but enough to prove that you are not just taking the mickey.

[Rockhopper]

The law says you can only drive to a pre booked MOT test with no MOT or tax so you need to ring up, book one and ask them to note your reg number in the log. I've found they often don't ask for the reg number so you need to make sure you tell them!
Of course you need insurance.

[Chipstick]

Finally found the problem - just forgot to post it. When the engine was rebuilt the CO sensors were misfitted (across the exhaust banks) This confused the EMU. Quite a job to get sorted but all working now.

[enuff_zed]

Finally found the problem - just forgot to post it. When the engine was rebuilt the CO sensors were misfitted (across the exhaust banks) This confused the EMU. Quite a job to get sorted but all working now.

A confused EMU!!!
Is that the same as a baffled ostrich ?