C8 2.2HDi really hates hills - turbo or DPF issue perhaps?

[tearing hair out]

I bought a £45 new one from Autodoc and instantly wondered if I'd made a bad choice... I guess I'll find out when it arrives.

[Rp0thejester]

I'm not a fan of Autodoc, online automotive are my go to company. I ordered springs from them, they didn't ship them as they knew they wouldn't fit so emailed me to get in contact with them. I did and the correct ones were sent next day. Better than being sent the wrong ones and then have to return them. Great customer service IMO and very reasonably if not cheap prices

[Rp0thejester]

Tearing, mine also shows fuel cap issue!! I'm assuming it's rubbish like tyre sensors

[tearing hair out]

Tearing, mine also shows fuel cap issue!! I'm assuming it's rubbish like tyre sensors

Mine is definitely faulty. The state changes if I unplug the sensor, but the (magnetic) switch doesn't trigger even when near a strong magnet. It looks pretty easy to change IF I can find one. Though I assume the ADDGO ECU must dose with additive periodically if the sensor is broken, since it's been like that for the 4 or so years I've owned the car.

I'm now manually connecting it (fuel cap removed), waiting 30 seconds, disconnecting it (fuel cap present) when I fuel it - the connector into the wiring loom is under the car about 50cm forward of the fuel cap. What I haven't done (and should do) is check that the pump makes a noice when I test it with Lexia. Should I ever figure out where I hid my Lexia.

[Rp0thejester]

So how do you know it's faulty? Is it changing your driving performance?

[MattBLancs]

I'm not sure I want them to rev it to the red line with the sensor disconnected though...

Don't forget, given the change in performance with it unplugged, you may well have been revving it to red line often with a dead MAF. I'd not be very worried personally.

I'm sure I read somewhere that the "diesel killing MOT redline smoke test" (i.e. sometimes known for cambelt snapping) is possibly the rate of engine deceleration when the pedal is released.

[tearing hair out]

It doesn't get over 3500 under load, even with my foot on the floor - which was the standard position until today. It definitely would have reached the red line unloaded though. I'll probably give the garage a choice of MOT with or without sensor and see what happens (unless the replacement arrives in time).

The cambelt is only 5000 miles old, so breaking it is at least unlikely.

[tearing hair out]

So how do you know it's faulty? Is it changing your driving performance?

The only indication is an error code read with a code reader. I don't think the main engine ECU cares much about the additive ECU, other then repeating the error when the additive level gets low - I couldn't tell that it was changing any performance, though I'm not sure how I would have known.

EDIT: See here for the error code: viewtopic.php?p=758575#p758575

[Rp0thejester]

It doesn't get over 3500 under load, even with my foot on the floor - which was the standard position until today. It definitely would have reached the red line unloaded though. I'll probably give the garage a choice of MOT with or without sensor and see what happens (unless the replacement arrives in time).

The cambelt is only 5000 miles old, so breaking it is at least unlikely.

I was pulling 4k revs today with MAF sensor disconnected and reminded myself several times of what the speed limit is. Did yours pull 4k at any point with MAF disconnected?

[tearing hair out]

And, with the power of hindsight, looking at the video on that very first post, I should probably have been suspicious that the measured airflow reading at 3000 rpm was only marginally higher than the reading at 1000 rpm. Intuitively, a factor of about 3 is probably what I should have expected...

[tearing hair out]

I was pulling 4k revs today with MAF sensor disconnected and reminded myself several times of what the speed limit is. Did yours pull 4k at any point with MAF disconnected?

Not sure. It's possible (it definitely would have easily hit 4k), but I tend to shift early - and most of the roads in Wales that were 30 are now 20. I was also being cautious on the grounds that it's in an odd state with the sensor missing and I didn't want to damage something (though I suspect it would have been fine).

EDIT: What I should have said is "With the faulty sensor, it doesn't even get to 3500 RPM..."

[Rp0thejester]

I agree, mine didn't get above 3500rpm with it connected, disconnected however, what a difference!! For the first time ever I was looking for hills rather than avoiding them. I think the driving without it connected did my car a world of good, blow them cobwebs out as to speak

[myglaren]

£25, Captain eBay to the rescue!

Be wary of cheap MAFs Ryan, they tend to be more expensive, they only seem to last a short time.
Get a Siemens or VDO (the same, VDO is a Siemens spinoff). I think I paid £135 for mine.

[Rp0thejester]

I've ordered it here,

if it's bad believe me I will tell you

[tearing hair out]

Fitted the replacement MAF, which seems to have done the trick - for the first time in months I have no EML and the correct performance at the same time. And just in time for the MOT, which passed.

Once again, I can be really lazy and accelerate (slowly) up hill from 20 in 3rd!

The old MAF doesn't LOOK too bad - not tried to clean it though.