BOFFIN NEEDED FOR CODE-BREAKING

[Noddy 99]

Hi, I mentioned this in a recent thread but have now opened up a specific line of enquiry.

Following months of really poor fuel economy, I have just RE-run a code check and it's coming up with the following:

1. State: Historic
Check component Y77/1 (Boost pressure regulator). Positioner signals fault
I cleared the code and this one DIDN'T reappear

2. State: Current
Check component B2/6 (Left hot film mass air sensor). Value is above limit
I cleared this code and it DID reappear

I'm getting the following live data:

Boost pressure = 1012 m/bar
Current injected quantity = 29.40 mm3 / Hub
Engine speed = 0 rpm
Intake air pressure = 1005 m/bar
Y94 (Quantity control valve) = 0%
B4/6 Rail Pressure Sensor = 2.10 bar
Pressure control valve = 10.94%
Electric fuel pump = OFF

Do I need to do this test with the engine RUNNING?

I recently did what Wighty suggested and cleaned out the batwing with Carb cleaner. I changed the air filters at the same time. No difference.

Apart from the fuel economy, the car is running fine.

W211 E280 CDi Sport
190PS
Automatic
Sept, 2009
110, 000 miles

All of this data means NOTHING to me so I'd be really grateful of some guidance before I go to have my wallet emptied...

Many thanks.

 

[M80]

How is the Lambda reading while running?

 

[Noddy 99]

The engine wasn't running. This was done with iCarSoft MB II and I vaguely recall reading that you have to have the ignition on but the engine off...

Which one is the lambda reading?

Thanks for your response.

 

[LostKiwi]

I'm guessing this is a diesel OM642.

Live values for the engine are with it running.
A hot air mass sensor fault may be the MAF but first check all connections, and check for boost leaks (split hoses are a favourite).

Failing that you could be up for a maf sensor.

 

[onefortheroad]

The engine wasn't running. This was done with iCarSoft MB II and I vaguely recall reading that you have to have the ignition on but the engine off...

Which one is the lambda reading?

Thanks for your response.

The O2 / lambda sensor talks to the mafs and fuelling is done accordingly. When it's goosed you usually get a fault to earth or something similar.

 

[M80]

Mine had poor consumption.
Later it came up with a MAF problem, nowt else.
I watched the Lambda readings as I drove, they didn't change.
A bitch to change, but there are tricks.
That sorted my problem.

 

[Noddy 99]

Mine had poor consumption.
Later it came up with a MAF problem, nowt else.
I watched the Lambda readings as I drove, they didn't change.
A bitch to change, but there are tricks.
That sorted my problem.

Sorry, what sorted your problem? Changing the MAF sensor or the lambda sensor?

 

[Noddy 99]

I'm guessing this is a diesel OM642.

Live values for the engine are with it running.
A hot air mass sensor fault may be the MAF but first check all connections, and check for boost leaks (split hoses are a favourite).

Failing that you could be up for a maf sensor.

Yes, the good old OM642...

Thanks for your reply. I'll get under the bonnet when it's running and do another code scan.

If I need another sensor, is that a part of the batwing? Can it be separated or is that a whole new batwing?

 

[onefortheroad]

A new lambda is £89 , 10 minute job to change if it comes out without strpping the threads in the exhaust. If it's a MAF you'll need a new or used batwing .

 

[mioba]

I'm guessing this is a diesel OM642.

Live values for the engine are with it running.
A hot air mass sensor fault may be the MAF but first check all connections, and check for boost leaks (split hoses are a favourite).

Failing that you could be up for a maf sensor.

If you had a boost leak you would be running rich or lean which is a different DTF to the MAF DTC.

 

[mioba]

Yes, the good old OM642...

Thanks for your reply. I'll get under the bonnet when it's running and do another code scan.

If I need another sensor, is that a part of the batwing? Can it be separated or is that a whole new batwing?

You know the horrible answer

 

[Noddy 99]

If you had a boost leak you would be running rich or lean which is a different DTF to the MAF DTC.

I don't know what a DTF is and I don't know what a DTC is... With me, you have to imagine you're talking to a 5-yr-old...

And are you saying that running rich (which would explain the horrendous consumption) would throw up a different code to the ones I've got? Does this seem to suggest that a boost leak is NOT the problem?

Many thanks.

 

[M80]

For me it was the exhaust oxygen Lambda) senosr.

Not sure where on yours. But spray with penetrating fluid, run, spray again. Remove when hot, with a v good v long reach socket. I fashioned a jubilee over the socket to stop it splaying, as it didn't want to shift. Until hot, then it near fell out.

 

[onefortheroad]

To remove the old sensor , chop off the wiring and get a good ring spanner on the nut . To refit use an open ended spanner , gently .

This is how I went about it anyway.

 

[Noddy 99]

I had one of the sensors replaced about a year ago because it was throwing up a code.

I'm getting no lambda-related codes this time so I'm not convinced that's where the problem lies...

Thanks to everyone for the contributions.

 

[onefortheroad]

2. State: Current
Check component B2/6 (Left hot film mass air sensor). Value is above limit
I cleared this code and it DID reappear

Seems to be where the issue is.

 

[Noddy 99]

Ordered a new batwing off Ebay. £178. Not tooooo bad, in the big scheme of things...

I'll report back anon...

 

[ajlsl600]

To remove the old sensor , chop off the wiring and get a good ring spanner on the nut . To refit use an open ended spanner , gently .

This is how I went about it anyway.

Spot on...once ur sure its goosed!!

 

[alexanderfoti]

2. State: Current
Check component B2/6 (Left hot film mass air sensor). Value is above limit

In my experience this is usually caused by a boost leak (Air mass is higher than it should be vs calculated value), this would also correlate with your poor fuel economy.

 

[Noddy 99]

2. State: Current
Check component B2/6 (Left hot film mass air sensor). Value is above limit

In my experience this is usually caused by a boost leak (Air mass is higher than it should be vs calculated value), this would also correlate with your poor fuel economy.

Many thanks for that. I've stuck my head under the bonnet but can't really detect anything. I may ask my local garage to have a look.

Just for clarification: does this mean the batwing is faulty or that it's working perfectly well and picking up something ELSE which is faulty?