Golf 2.0 8V SE - POOR Fuel Consumption

[Bora Sport]

Someone may correct me if I'm wrong but I think you can unplug the maf and if it runs better when it is unplugged, it is sure sign that it is stuffed.

[CraigR]

^ I have heard that too, but someone said to only do it on short journeys, not sure why. I will give that a bash tomorrow though. I spoke with a VW tech, and he has been running his eBay MAF from China for months without any issues, it was only $23 so I purchased one as well. Doesn't need to last a lifetime, I'll replace it with genuine when required.

[CraigR]

I got an OBDeleven the other day so I scanned the car and got the following issues, which I later googled and seems to be a very common issue. MAF replacement and o2 sensors seem to be the culprits, but its a bit annoying it can't be pin pointed.

P1128 - Static - Bank 1, mixture adaptation (mult)
P0171 - Static - Fuel trim, Bank1

Definitely not running lean, I've never seen so much black smoke before haha!

[Bora Sport]

The maf in my Bora failed. Also my daughters 2004 Golf 2.0 was running rough and using a lot more fuel. It was the inlet water temperature sensor.

[CraigR]

Yep, that's also on the list of things that have been replaced and something that I will look into. Cheers for the input, greatly appreciated!

[CraigR]

Unplugged the MAF last night. Made absolutely no difference to the driveability and/or fuel economy. No CEL either.

[CraigR]

Received the eBay MAF yesterday and was looking forward to some normal fuel consumption. Took the car for a drive after installation and it has made absolutely no difference. It would appear that the MAF was replaced with an OEM Bosch item a couple of years ago.

I have some software that allows me to log certain parameters of the car, so logged the both o2 sensors. It would appear that bank 1 barely moves, if at all. Bank 2 seems to pick up a full lean condition after you let off the throttle in a spike fashion, which is what I would expect. I will upload the photo of the log soon.

Anyone have any ideas or suggestions before I order an o2 sensor?

$88 for a Bosch sensor isn't too bad either:
Bosch 0258010032 Oxygen Sensor - 4 Wires

[CraigR]

Can anyone shed any light on what is happening here? That green line doesn't seem to do a whole lot.

[CraigR]

Bit the bullet and ordered a front o2 sensor. Fingers crossed - will report back once fitted.

[CraigR]

Quick update for the benefit of others...

I replaced the front o2 sensor last night and the car instantly felt better to drive, bit more power and using acceptable amounts of fuel. Went for a short drive ~2km, and averaged 9-10L/100km. Fault codes cleared and have not come back on. Will do another update once the car has done a few more kms.

Here is the sensor that I purchased, cost $47 delivered from the UK and took about 2 weeks to get here. Better than $160+ from Aus.

Access Denied

[Bora Sport]

Hopefully it is fixed then.

[CraigR]

Fuel consumption before changing the o2 sensor - 19.8L/100km
Filled up at 220km - fuel light on

Fuel consumption after changing the o2 sensor - 9.9L/100km
Filled up at 530km - fuel light on

The front o2 sensor has paid for itself in just one tank of fuel. Very happy with that!