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GrampsE39

E39 530i Q. O2 sensor smoking in engine bay?

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Hi,

 

edit: forget the error on obd, the O2 sensor in the engine bay seems to be puffing smoke?!

 

The original problem:

 

(Does anyone know how many O2 sensors are fitted?

 

I’ve changed the two O2 sensors on the inlet manifold in the engine bay/drivers side of the car.

 

I’m still getting getting lean burn/bank O2 sensors on the EML on LPG fuel.  Fine on petrol.)

 

Thanks for any help!

Edited by GrampsE39
Found the issue smoking O2 sensor!

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Hi,
 
Does anyone know how many O2 sensors are fitted?
 
I’ve changed the two O2 sensors on the inlet manifold in the engine bay/drivers side of the car.
 
I’m still getting getting lean burn/bank O2 sensors on the EML on LPG fuel.  Fine on petrol.
 
Thanks for any help!
There are 4. But I would check the lpg trims it probably needs adjustment.

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Hi,
 
Thanks I couldn’t see any in the Haynes manual, will take another look under the car.
 
Will find out about the trims.
Cheers,
 
James.
There's 2 before the catalytic converters and 2 after

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The pre-cat ones which you have changed are mainly responsible for mixture setting and post cat ones for monitoring that cats are working properly. If the problem is only on LPG it must be something with LPG mixture settings. If there is still a code for both lambdas even on petrol it's most likely an air/vacuum leak.

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Hi,

 

Thanks for the suggestion.

 

I’ll clear the codes and check if anything recorded (might not throw the EML but a code might!) is up with running on petrol.

 

We did change the CCV and I’ll check with some WD40 if there are any air leaks.

 

Thanks!

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If it is running fine on petrol with no lights and trims ok (no vacuum leak), then it's either a bad LPG map or worn LPG injectors or both. Which LPG injectors do you have and how old are they (mileage covered)? Has it been like this from day one or it started occurring at some point after LPG had been fitted. P.S. O2 sensors are on the exhaust manifold, not the inlet one.

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Ok I’ve been telling my Dad I can smell LPG in the cabin when he drives.  Thought he had gas...

 

Then today I tried a gas sensor in the cabin. Bingo LPG.  Tried the engine bay and had a leak somewhere.  Slight misfire on idle revs petrol or worse on LPG.

 

Then noticed a puff of light smoke that my Dad thought I was mad as he can’t see it.

 

Now the smoke was smelling foul or LPG but difficult to see.  I think it’s coming from the O2 sensor nearest to the front. Hope it’s not the head gasket or a leak from changing the thermostat.

 

I only changed the top 2 sensors 1-2 years ago.  

 

Engine light is on for mixture and lean O2 sensor.

 

New O2 sensor time? Tighten existing one? Not sure what next.

 

Edited by GrampsE39

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I’d also check the temp sensor on the lpg reducer/vaporiser, as I had a gas converted car that wasn’t happy on gas, changed injectors and filters etc, turns out the fault was the little screw in temp sensor, initially I unplugged it and the car ran much better on gas as a result, swapped it for a new one and plugged back in and all is well again. Worth considering 

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Thanks, I’ll check again but the vaporiser didn’t seem to have a temp sensor I can see and nothing is coming out of it.

 

The smoke looks like the O2 sensor is burning releasing some smoke/stinks of LPG.

 

I finally have an O2 sensor ready to be put in once it stops raining. 

Edited by GrampsE39
Missed word

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