D2 and MAF - Mass Air Flow Sensor

[astormsau]

Hi everyone,
Just wanting to share recent experience with my D2 which i got about 4 months ago (125,000kms on the clock).

No warning lights, and to me it drove ok. My mate, a LR mechanic, gave it a service on the weekend, took it for a bit of a spin, and told me its not performing well. To me the car has always run fine, 4L V8 in a big car so i wasnt expecting a rocket ship. His definition of symptoms; at 3100rpm under heavyish acceleration the motor would drop back to about 3000rpm as if it was changing gear (it wasnt but i thought it might have been considering it and then decided not to) and then continue to rev up through the range. And after driving like that a bit, when you hop out, a bad smell of rotten eggs. Also intermittantly he said, the performance when you did kick it back to a lower gear, was not too good...

I was getting about 18L/100km around town and 16L/100km on the highway so not bad economy. Wasnt idling rough or anything like that.

1. put it on testbook, showed a faulty left hand oxygen sensor and that was it, no MAF sensor issues or any other codes, so we ordered a new oxygen sensor.

2. removed the MAF and cleaned it out with circuit board spray. Started car without MAF connected and it ran okay but smelt really foul with rough idle, so obviously MAF was doing something.

3. refitted MAF and she seemed to run a bit better, but still had miss at 3100RPM. waited for oxy sensor.

4. Fitted new oxy sensor, ran a bit better but still missing at 3100rpm.

5. Replaced MAF sensor this morning, no longer missing at 3100rpm. Better acceleration, less need to plant the foot to kick down gears to maintain speed on hills.

Has totally transformed the car - and most likely the oxygen sensor wasnt faulting but merely reading as bad because of the MAF sensor issue - not unhappy about replacing oxy sensor as I am aware that alot of these sensors will eventually die anyhow and I plan on keeping this beast for a while.. and i believe when i have vapour injection gas installed, it might take a signal feed off the new oxy sensor so best to have that all sorted.

So just sharing my experience, in most instances MAF can be a problem in poor performance, and in addition, just because you clean it and it gets a bit better, doesnt mean its back to the best it can be. In my case i had a definate way to analyse this - the miss at 3100RPM which I can only put down to some kind of fault reading at that point which caused the ECU to change the way it was deliverying fuel/spark or whatever (im a PC tech, not a mechanic) which caused the hiccup and the maybe reverting to the default non-MAF settings.

Hope this gives someone some good info/insights.

Andrew

[29dinosaur]

where are you located??

[justinc]

The MAF sensor failure on these is so common, I keep the sensors on the shelf now:(
The auto trans shift points and overall behaviour is affected by this little item also, so if you D2 V8i or even Td5 is suffering and not pulling well, especially cold, then I would suspect it. The Testbook and rovacom usually won't show faults unless it has completely failed. I can get realtime kg/hr of mass airflow readings using rovacom while driving, and this immediately shows up a faulty / failing A/F meter.

JC

[Pedro_The_Swift]

I think my record for a MAF change after half a dozen or so was 90 secs,,,:D:p


you can get kits to just replace the sensor/wire/electronics.


My saga---
http://www.aulro.com/afvb/technical-chatter/57174-d2-missing-under-load.html

[4X4V8]

Just an update on my 1999 D2 V8 MAF sensor - there is a thread here somewhere on how I had codes thrown showing a lean or rich mixture (this seems a common hint that a MAF is playing up) and suspect (high) fuel consumption.

I tried cleaning the original sensor with contact cleaner but it made no difference

I replaced my OE Bosch MAF sensor with a unit made by Intermotor. It was much cheaper that the Bosch replacement ($180 vs abt $350).

After two months driving it has fixed the codes and fuel economy seems a little better overall - although this aspect I cannot be 100 percent sure about (but codes are gone).

I have noticed something new: the car does hesitate slightly after cold start-up (probably accentuated because it is a manual). It is not bad enough to make me want to change it again but I wonder if this is the 'cost' of getting the cheaper, non-genuine replacement.

[astormsau]

where are you located??

hi mate,
i am located in Melb in vermont.

just an update, after 24 hrs of having the new MAF installed, and as per other comments here i can verify:

1. when cold, the car performs much better, i have a steep hill climb about 1km from my front door and the car doesnt labour as much or need anywhere near as much throttle to get up it at reasonable speed

2. the miss at 3100rpm has not come back

3. the car has heaps more power when you are just cruising along at 60km/hr... it is not kicking back as much to get up hills, its holding its current gear as im not needing to step on the pedal to make it maintain speed

4. the automatic box is changing gears differently, it seems to hold them a bit longer which is much better, rather than just jumping into 4th and then locking up the convertor...

generally its just alot more responsive and feels like im driving a V8!
for me who has only got the car a few months back, its like its new all over again!

id assume the MAF just slowly degrades over time.

Andrew

[nice1guv]

The auto trans shift points and overall behaviour is affected by this little item also, so if you D2 V8i or even Td5 is suffering and not pulling well, especially cold, then I would suspect it.



4. the automatic box is changing gears differently, it seems to hold them a bit longer which is much better, rather than just jumping into 4th and then locking up the convertor...

Does the MAF also play a part in the shift pattern of a D1 V8i?

[ozscott]

I dealt with Webcon in the UK - what was Webber carbs...very good brand over the years. They sent me 2 new MAFS on their aftermarket type for my D2. Both made the vehicle do very strange things and big loss of power flat spot between 2000 rpm and 3000 rpm then it took off again. They ended up refunding all money and my postage of the items back to them - very good company to deal with. They said that their MAFS worked fine on UK D2s..they resolved not to sell them to overseas countries again on the strength of their experience with mine.

I bought a new one from LR for $sh.tloads and it ran like a champ. The old one got fried because with my LPG I had a breather pipe off the pass side rocker cover back to the air box to make sure no gas found its way to the sump. Unfortunately it sucked oil (tiny bits here and there) into the air intake tube and it covered the MAF and completely stalled the can one day...I had to take off the fitting from the MAF (connector that is) and could drive it relatively well on a default setting then. Tried cleaning the old one but it was still pretty ordinary.

Cheers

[tempestv8]

I've had my DII V8 from new since 1999 and have replaced the MAF twice now over the period of time that I've owned it.

Both times that I've replaced the MAF with a genuine one, the V8 started to run really well, and revs out very cleanly.

It's a shame that the ECU does not give any warnings when the MAF degrades, so you could be using lots of fuel without knowing that it can be fixed via a MAF replacement.

Anyone know where to buy these MAF sensors cheaper than from your LR dealer? Looking at the sensor, it looks like a generic BMW MAF, as I've seen it (visually looks identical) on a 7 series Bimmer as well.

[ozscott]

Lawrance -the 7 series had pretty much an identical Bosch Motronic engine man' system. Even though it makes sense that they have the same MAF I wouldnt bet on it because the LR version of the En Man' was programmed differently for low down torque - off road style. My experience leads me to the view that I wouldnt try another one again.

Its absolute madness the cost of these things though...seriously you can buy a complete Webber carby for similar dollars or 3 tyres...where is the sense in all that

[ozscott]

If it were not for the fact that my LPG doesnt care what the MAF is doing (its Lambda controlled - uses left bank O2 for its tune) I would seriously consider a Haltec or Motec using a MAP not MAF and program it the way I wanted.

Cheers

[4X4V8]

Anyone know where to buy these MAF sensors cheaper than from your LR dealer? Looking at the sensor, it looks like a generic BMW MAF, as I've seen it (visually looks identical) on a 7 series Bimmer as well. Intermotor 19609

Air Mass Sensor (Sensor Only)

Replaces BMW (then lists 2 BMW part numbers)
Bosch
Mercedes
Rover MHK 100800

Cost: around $180

TR Spares
5 Fairford Rd
Padstow, NSW 2211
(02) 9709 5611

See my comments in previous post above on how this sensor is going in my D2 V8.

[ozscott]

4X4 V8 - is it the exact same spec' as the original one?

Cheers

[lizard322]

An ignorant question but can someone tell me exactly where the MAF sensor is located on Td5? Are there any removal precautions to note?

Thanks

[Pedro_The_Swift]

ASSUMING its the same as the V8---
its inline with the air intake, after the filter and before,,, well before what ever the diesels have,,
its black, has 3 large overcam clips on each end and a square section in the middle, length is about 9 inches???

[johnb44]

i found mine today and it was filthy on the turbo desiel its about 75mm long directly after the air cleaner box [ well i hope thats it ] 2 clips on one side and a hose clamp on the other wires and a square box on top :eek:

gave it a good spray and it went from black to a bright metal finish :angel:

[ozscott]

Pedro - it seems to be in the air box mate - I have a TD5 air box to replace my old one for the V8.

Cheers

[scarry]

i found mine today and it was filthy

Thats what kills them....The air cleaner box on the D2 isnt the greatest,& the MAF sensor gets dirty.

Some people have cleaned them with success..,using electronics cleaner or something similar.

Search is your friend,i think you can get MAF cleaner from Auto Barn or similar.

[Pedro_The_Swift]

Pedro - it seems to be in the air box mate - I have a TD5 air box to replace my old one for the V8.

Cheers

your kidding,, right?

[ozscott]

Mate - there is a probe in the lid of the TD5 airbox with a couple of wires hanging off...dont know what its for but guessed at it being a primitive looking hot wire or air mass sensor...

Cheers

[ozscott]

but obviously based on the above the AMS is not in the air box lid...so the mystery is what is that probe in the air box for?

Cheers

PS. Why would an air mass sensor not work in the air box as long as it was (as this one I have is) above, on the clean side, of the filter?

[justinc]

The sensor in the airbox is the ambient air sensor, it is an input into the ECU for incoming air temperature/ pressure.

JC

[ozscott]

That makes sense I guess - the MAF in the V8s does temp as well...thats the data that goes to the scanguages etc

[ajbdisco2]

Hi just wondering how long after replacement of MAF should you notice the difference in performance?

[Urban Panzer]

If we are talking TD5, then theres no real "Loss" or performance when it dies, only a little bit when going up looooooong steep climbs, but not much if im honest. The same goes for the MPG, I had not really noticed it had dropped, but def noticed it had gone back up again once the new one was on and fitted.

The thing is, if its dead, replace it and check its working and then you have peace of mind its all as it should be imo.

The MAF does also "controls" the EGR system, but mine is removed completely, so its not doing anything there anyway.

[Pedro_The_Swift]

and if its a V8,, instantly,,,

[ajbdisco2]

its V8 duel fuel. Replaced the MAF and it ran worse, was told to let it run for 10klms and see if there was any improvement, there wasnt. So i swapped it back. The trouble is going up hills you really have to put your foot down and it seems to be indecisive on which gear it wants. It sometimes revs out to 4500rpm!! A bit scary dont want to blow the thing up. It was stalling on gas and idling really low so i have had it back to the gas place 3 times. Its no longer stalling but idle still fluctuates between 350-800rpm.
We have tried MAF sensor, new points and leads, transmission service and gas service. Still no clue maybe the catalytic converter???

[astormsau]

its V8 duel fuel. Replaced the MAF and it ran worse, was told to let it run for 10klms and see if there was any improvement, there wasnt. So i swapped it back. The trouble is going up hills you really have to put your foot down and it seems to be indecisive on which gear it wants. It sometimes revs out to 4500rpm!! A bit scary dont want to blow the thing up. It was stalling on gas and idling really low so i have had it back to the gas place 3 times. Its no longer stalling but idle still fluctuates between 350-800rpm.
We have tried MAF sensor, new points and leads, transmission service and gas service. Still no clue maybe the catalytic converter???

You need to check your o2 sensors. There are two, they are located on the exhaust and are used by direct injection gas systems to determine the correct mixture of LPG and other timings. When they are faulty on a V8 running on petrol the ECU defaults back to its default settings which are ok for petrol - it runs a bit rich but idles okay and so forth. When the o2 sensors arent working and you have LPG which relies on them, you will get erratic idle and the car wont have as much power or run as smoothly.

You could also check the contacts to the MAF to ensure they are clean and also ensure you are using a genuine MAF - non gen ones dont seem to work as well based on comments from other forum users.

Another thing to check on your car is the idle control valve which is a cylindrical thing located on the top of your inlet manifold with some pipes running into it and then out again, its a magnetically controlled valve which controls the amount of air the car lets into the engine, and if it gets too dirty it can not work correctly and cause issues with idling. When you start your car cold it should idle at 1200rpm for about 30 seconds and then drop to 800-900, if it isnt doing this then look at the idle air contol valve.

Andrew

[Pedro_The_Swift]

It sometimes revs out to 4500rpm!!

Does it the world of good,,,;)

I am "under instructions" to ensure mine see's "over 5" once a month,,,

[Cannon]

Does it the world of good,,,;)

I am "under instructions" to ensure mine see's "over 5" once a month,,,
Really???

Why is that?

I'm happy to do it for fun, but if I had a valid reason...well even better:twisted:

[astormsau]

oh come on there's nothing up there at 5 anyhow, just alot of ACE pump noise :)

[Pedro_The_Swift]

just max HP,,,

so, the first time you ever need to hold a gear,,
you (and the car) will be in uncharted territory.
:eek:


my ACE pump makes noise?:o
:p

[Clarky]

Just to add to this, the dirty sensor in mine was affecting the gear change in the auto box. Wouldnt change into 4th gear till it hit 80 klm/h, so was reving at 2000rpm at 60 klm/h, instead of about 1500rpm.
Also the car seemed to be surging when going uphill at speed.
I gave the sensor a good going over with the air compressor and everything seems to be working ok,..... at the moment anyway.

[ozscott]

The MAF sensor failure on these is so common, I keep the sensors on the shelf now:(
....

JC

Just...it is interesting that these things go...cause they are straight German and nothing to do with Rover (:D:D:D:D). I see on Merc and BMW sites that they have the same dramas...same part in some instances.

It makes me wonder whether for term ownership whether a Haltech for eg with a MAP and air temp sensor would be worth the outlay (and there is the programmability factor too there)

Cheers

[Tombie]

If we are talking TD5, then theres no real "Loss" or performance when it dies, only a little bit when going up looooooong steep climbs, but not much if im honest. The same goes for the MPG, I had not really noticed it had dropped, but def noticed it had gone back up again once the new one was on and fitted.

The thing is, if its dead, replace it and check its working and then you have peace of mind its all as it should be imo.

The MAF does also "controls" the EGR system, but mine is removed completely, so its not doing anything there anyway.

But a faulty MAF on a TD5 makes the Auto box turn to slush!