CEL on start up - mixture too lean

[BIGXPX]

Hi
New to the forum and hope to learn from everyone.
I have an issue which I can't seem to resolve.

On cold start up, if I let the car idle for a couple of minutes I get the EML light.
Code reader brings up 118010.
I can clear the code. If I then leave the car for say 30min and start the car and let it idle i have no code.
If I stat from cold start and rev a little I get no CEL.

There is no loss of power.
Coils and sparks are less than 1000 miles old.

Any help appreciated

[technician117]

Originally Posted by BIGXPX

Hi
New to the forum and hope to learn from everyone.
I have an issue which I can't seem to resolve.

On cold start up, if I let the car idle for a couple of minutes I get the EML light.
Code reader brings up 118010.
I can clear the code. If I then leave the car for say 30min and start the car and let it idle i have no code.
If I stat from cold start and rev a little I get no CEL.

There is no loss of power.
Coils and sparks are less than 1000 miles old.

Any help appreciated

Could be bad precat O2's or possibly MAF's. How many miles on the car and those components?

[BIGXPX]

MAF's are 1000 miles old and 50k on the motor

[technician117]

Originally Posted by BIGXPX

MAF's are 1000 miles old and 50k on the motor

So the precat (also known as primary) o2 sensors are original? If so, I would at least start there as they should be done around 50k miles anyway.

[BIGXPX]

Thanks.
Can I start by giving them a clean first and if so what with.
I'm looking to go catless in the next few weeks so will this make the o2 sensors obsolete

[technician117]

Originally Posted by BIGXPX

Thanks.
Can I start by giving them a clean first and if so what with.
I'm looking to go catless in the next few weeks so will this make the o2 sensors obsolete

No and no.

No you can't clean them and no, catless DP's don't eliminate your precat O2's. They are required for proper fueling.

They're like $75 each for Bosch replacements.

[BIGXPX]

Originally Posted by technician117

No and no.

No you can't clean them and no, catless DP's don't eliminate your precat O2's. They are required for proper fueling.

They're like $75 each for Bosch replacements.

the lamda sensor? Part no. 11157843150

[technician117]

Originally Posted by BIGXPX

the lamda sensor? Part no. 11157843150

Yes, the lambda sensors that are located right in front of the converter element. The decat pipes still have them in the same location.

I just noticed you are in the UK, so I can't comment on pricing. In the US, you can order from Rockauto.com for OEM Bosch. AFAIR they are roughly $75 each. I don't know what vendors you have over the pond, but there is no reason to buy direct from BMW for the same part.

[BIGXPX]

Thanks. I can get the Bosch lambda for £55 each.