Two days ago I replaced my last two injectors with low milage used units... smoking has reduced drastically, and my power has returned quite a bit. Having said that, and accepting that at least one of my remaining injectors was probably faulty, I still don't think she's running lean enough.. O2 air/ fuel readings are in the 0,2 range, and my MAF values are still doubtful... 11 to 13 on idle. But as you say, trying to find the expected values is proving very difficult. Here in SA I find it difficult to get a "Diagnose Dan" type guy to really dig into the data and offer any helpful information, it's always just "okay, maybe it's your 02 sensor, go but a new one"
Nodge68
Well-Known Member
The air path calibration is important, which is why LR specifically call for it.Good evening, all.
I don't mean to hijack this thread, but I have a very similar issue here with my 2008 Freelander 2 TD4.
I don't have any black smoke issues, and the car is well-serviced and otherwise seems to be running quite well for its age. I noticed that fuel consumption has crept up to 10.7L/100KM (about 26MPG) so I did some searches online and found out how to test the MAF. I back-probed it with a multimeter and the voltage readings were all over the place, so I replaced it with a Pierburg 7.22184.24.0 and checked the readings with a newly acquired OBD2 reader. It was showing 12.8g/s at idle, 55g/s cruising around 2000RPM, and maybe 120g/s under load at 3000RPM, which seems significantly out of spec based on what I had found online:
Voltage Output (Signal): Analog, ~0.5–4.5 V.
I had access to a Bosch '0 986 280 703' model MAF, which is also supposed to be compatible with MHK501040 specifications, but it gave very similar results... 13g/s idling at 790RPM.
- Idle (2–5 g/s): ~0.5–1.5 V.
- Cruising (10–20 g/s): ~2.0–3.0 V.
- High Load (30–50 g/s): ~3.5–4.5 V.
@Nodge68 I saw your recommendation about the air path recalibration elsewhere, so I queried this with my local LR specialist and he said they never do them for MAF replacements; only for "throttle, EGR and turbo actuator", but that they could try doing a recalibration if I want to. Is there any way to have the ECM recalibrate itself through a battery disconnect, or using OBD2 apps, or is this something that absolutely must be done by an LR mechanic? I trust the mechanic completely - I'm just weighing the cost of the labour against the cost of the extra fuel consumption
The ECM isn't self learning, so needs to be told what the correct values of the sensors are.
Whe the APC is carried out, the MAF is one of the units under calibration, along with the correct (green) or out of spec (red) flag.
Here's screen shots of the actual calibration being carried out. Note the 4 units being calibrated. If the EGR is blanked, it'll get a red flag, and sometimes the software will refuse to complete the calculation, but other times it will.
Fantastic, thanks for the info.
Apart from poor fuel economy and general inefficiency, is there any reason to do the APC urgently? If not, I’ll just ask them to do this during its next service, rather than pay to have it done separately.
