TD5 runs similar with and without MAF

Hi all. Since purchasing my D2 it's been 'sluggish'. I kind of assumed they were like that since I have limited experience with them! But I've read a lot on here about this sort of performance being related to the MAF sensor. So I took mine off, cleaned it with carb cleaner. Re installed it. Measured voltage to pins during idle (1v) and under load (maybe 4v). Which I think I remember is lower than it should be? But still something.

Yesterday I disconnected it and went for a drive. It seemed the same. Except different.

My wife in the passenger seat commented that the car seemed to be running 'smoother'! I think actually what she was noticing was the absence of clunky shifts from the auto gearbox (maybe a separate issue) but these disappear with the MAF disconnected resulting in a drive that 'feels smoother'.

I tried it in S mode and the clunky gear changing came back a little.

In summary, the cars performance seems mostly unchanged. Most people would not notice any difference. Implying my MAF sensor isn't doing anything. Except for the slightly smoother gear changing.

How could this be? Is the default mapping from the ECU a flatter response curve so that the gearbox doesnt have to change so frequently?

Does all this mean I should replace my MAF sensor?

Car is a stock 2004 TD5 Auto. No EGR messing about. Tyres factory size.

NZ Pablo said:

Measured voltage to pins during idle (1v) and under load (maybe 4v). Which I think I remember is lower than it should be? But still something.......

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Even if it's reading and not fubar your MAF is not OK.

NZ Pablo said:

How could this be? Is the default mapping from the ECU a flatter response curve so that the gearbox doesnt have to change so frequently?
Does all this mean I should replace my MAF sensor?

Click to expand...

On Eu3 engines the default for unplugged MAF is the Eu2 mapping as te fuelling calculation is based on MAP/rpm readings while the MAF is only for EGR but on the Eu3 the MAF is the main elementvfor fuelling. Only the expensive genuine (MHK100620LR) sensor is completely reliable, any other aftermarket(VDO included) are a lottery and it can run the same or worst than with it unplugged so bite the bullet for the genuine one or better drive it with it unplugged(if everything else is OK it will run like a good Eu2 engine without probs if the EGR is bypassed) but in this case clean the MAP and the AAP(airbox) sensors cos these are the most important.... see this https://www.landyzone.co.uk/land-rover/d2-td5-cutting-out-when-warm.326582/#post-4193511

aamof your's can be sluggish i you still have the cathalyst fitted cos it's old enough to be quite clogged so the boost can't rise enough, also check if your wastegate is not stuck open

Interesting read guys

On my way to London last week! Mine was playing up, she was a bit sluggish on the hill climbs (and on some flats)?
Was giving it a bit on the revs, where it would kick in after a few seconds (20-40) and continue as normal?

So will take a look at the above points and link, and let you know if any change on mine? Over the next week!

Kev

Badger688 said:

Interesting read guys

On my way to London last week! Mine was playing up, she was a bit sluggish on the hill climbs (and on some flats)?
Was giving it a bit on the revs, where it would kick in after a few seconds (20-40) and continue as normal?

So will take a look at the above points and link, and let you know if any change on mine? Over the next week!

Kev

Click to expand...

All you have to do is to unplug the MAF and see if it runs better that way or not...if it runs better drive it so untill you replace the MAF with genuine or uplugged for eternity rather than use an aftermarket(provided it's Eu3 engine, if it's Eu2 with bypassed EGR the MAF is quite irrelevant)

I have late 2003.

Just buy a new genuine MAF.

And make sure boost is correct.
No MAF or dodgy are a lot worse.

Chaps,
Been working slowly on a bench running TD5 before vehicle install.
She’s running but just been brief runs. Seems I’m getting no throttle response on runs. Currently MAF and MAP nonexistent as don’t have intake tube or airbox.
Been reading around the web and a lot of different opinions on having MAF vs MAP plugged and unplugged etc.
I don’t have an air box and am having to source one…
Would you all support getting an air box with a MAP port…or not to bother?

Any other info on this much appreciated!

TIA

Alistair Davidson said:

Currently MAF and MAP nonexistent as don’t have intake tube or airbox.

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I think you are confusing the MAP sensor(which is in the inlet manifold) with the AAP(in the airbox)... with MAF unplugged any Td5 should run well as it has a default for close to optimal performance but with the AAP is a different story especilly if the engine is 15P(Eu3 tune) and automatic too... the default for AAP open circuit is with reduced performance so better fit it ASAP but for Eu3 the MAF is important as well, see post #2 in this thread