Td5 D2 engine - MAF Sensor (3)

The new MAF sensor arrived today from JGS4X4. I have bought from them before and when you consider that I ordered it on Friday and it arrived the following Monday morning, that's a good service..

There is a lot of discussion out there about only buying the official LR OEM sensor. All the others are deemed to be cheap nasty copies that give 'false readings' in use. It's difficult to qualify statements like that without testing a whole range of these sensors. It's easier to accept that expense equals quality.

A new 'Siemens' branded unit is north of £80. Other unbranded or 'aftermarket' units can be had from £15 upwards. There is even a busy second-hand market in these things, - plenty of ways to be landed with a turkey!

So it comes down to cash flow. Even the parts suppliers must consider this when deciding which manufacturer/distributor to get their stock from. I also like to think reputable suppliers will have one eye on their own reputation for selling quality parts...

When looking around for the replacement sensor, I priced the local independent LR garage who stocked Britpart for £35 .  JGS4X4 where cheaper by £8 , but didn't state what 'make' it was. (listed as unbranded). I took the gamble figuring I could then buy a new stock air filter with the difference.

That whole 'Britpart' question turned up again. I got to thinking that as they seem to offer a 2 - year guarantee on everything these days (no doubt because of the bad rep) they should be back up there. So I was kind of wanting the new MAF to be a Britpart..

This is what I ended up with. A cheap and cheerful pattern copy. At least the 'stock' date is recent. There is no branding or any markings at all on the sensor body except for the airflow direction arrows. 

Studying the unit closely gave me the impression that it was maybe even a refurbished unit. There were more clues as to the way the sensor unit is mounted in the tubular body. Excess bits of a black rubbery mastic type glue were to be seen.

But by far the biggest difference was with the sensor wires. I was expecting the same arrangement with two fragile wires but instead this sensor has two resistors soldered in place. 

It is possible to read off the colour bands on the larger resistor. I have no idea how this set up will compare to the original one. I can only hope it gives 'correct ' readings..

Another image of the new sensor. Of interest here is the small hole visible on the mirrored base-plate of the sensor. Whats that about I wonder? Also, that mirrored surface is not as smooth as the original and has what looks like fingerprints on its surface!!

So, all things considered, I tried the resistance tests across the pin out terminals..

NEW MAF RESISTANCES 

PIN 1-2  =  194K OHM

PIN 1-3  =  1670M OHM

PIN 2-3  =  1960M OHM

At least I got a reading even though they are nothing like I was expecting. Think I'm in un-chartered territory here..

15/03/17 - Went ahead today and fitted the new MAF filter to Hx. Went out on a test run. Right from the start it was possible to feel that the engine was more lively and willing. 

Took the Nanocom along and plugged in to the OBD. At idle, the 'instruments' diagnostic gave the following..

IDLE  SPEED  -  744RPM

COOLANT  -  59.5°C

TURBO PRESSURE  -  0.04

AMBI PRESSURE  -  102.37

AIR FLOW  -  64.5 G/HR

AIR INLET TEMP  -  25.3°C

FUEL TEMP  -  53°C

The new MAF filter now measures the correct airflow value at idle. It should be in the range of 55 - 65 g/hr. Glad to see its right up there.!

Air flow at 2k rpm is now 343g/hr. The old filter was showing 200g/hr.

I continued to drive around with the Nanocom connected, but I gave up looking at the numbers in favour of enjoying the drive! 

The Nanocom offers the facility of recording data to a SD card so that it can be studied later rather then driving with one eye on it trying to remember the values!!  - a lot safer.

So, to conclude, replacing the original MAF sensor with a cheap and cheerful copy has brought the engine back alive. 

Let's see how long that lasts.