TD5 Air Filter Housing Lid

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tom1979

tom1979

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Can anyone tell me if the filter housing lids which also house the AAP are different between the 3 pin and 4 pin AAP's ? I need to replace mine, which has stamped on it PHB102880 but a google suggests this is the entire housing. If they are the same between 10P and 15P engines that'll be much easier to find one.
cheers
 
sierrafery said:
The lid's p/n's are PHC100570 superseded by PHC000010 and PHC100740 but according to the VIN range in the identifier the split is from XA175541 which is 1999 so get one according to the VIN(i presume it's about your defender) see nr 16 here http://www.allbrit.de/UNI.cfm?PAGE=759190&SPRACHE=EN
Click to expand...

Cheers! My VIN starts YA189*** so presumably the early ones were for the very early ones (mines 2000). Do you know what the difference between them is? There are limited pictures diagrams about of them - perhaps the very early ones didn't have the little nipple for the EGR hose ?
 
Well I got the right air filter lid, fitted nicely and also fitted the AAP sensor properly fitted now. Now I don't know what damage leaving it cable tied in the engine bay has done but I don't think my AAP sensor is reading right! Drops down from 99 to 90 kpa, which in turn is causing overboost! Is this kind of drop normal ?? The overboost occurred at around 2:24 and 3:47 in the file, when the AAP was at its lowest! I would have thought a low AAP reading would allow more boost not reduce it

aap reading 13042018.JPG
 
The boost is calculated by the ECU extractring the AAP from MAP reading so if at let's say MAP = 235 and AAP = 100 it means 135Kpa(1.35 bar) boost which is below the 142 overboost limit so if the AAP drops to 90 the boost will be 145 above the limit.... so high drop in the AAP means that there's a restriction in the intake before the sensor.... make a short drive without the air filter and see then and if it's good put a new good brand one or a high flow filter...if you have snorkel make sure the intake was not restricted where it was fitted or something
 
sierrafery said:
The boost is calculated by the ECU extractring the AAP from MAP reading so if at let's say MAP = 235 and AAP = 100 it means 135Kpa(1.35 bar) boost which is below the 142 overboost limit so if the AAP drops to 90 the boost will be 145 above the limit.... so high drop in the AAP means that there's a restriction in the intake before the sensor.... make a short drive without the air filter and see then and if it's good put a new good brand one or a high flow filter...if you have snorkel make sure the intake was not restricted where it was fitted or something
Click to expand...


Cheers, I was just looking at that document you sent me previously which states "

AAP(ambient pressure) = real ambient pressure on barometer in kPa, around 100


must drop up to 2 units to 3000+rpm, more decreasing of that value related to the

acceleration should indicate that the air beyond the filter is less than required.

"

Looking at the airflow though that's getting up to 670kg/hr, much more than that and I'll have other problems unless I unplug the MAF.
 
It's not necessary that the air mass to grow if the intake is free cos if the AAP is higher the boost will be higher too at the same air flow so the ECU will reduce the rpm a bit at that point (i dont mean overboost) which will reduce the MAF reading too....all these values are part of the addaptive strategy and are intrerdependent
 
sierrafery said:
It's not necessary that the air mass to grow if the intake is free cos if the AAP is higher the boost will be higher too at the same air flow so the ECU will reduce the rpm a bit at that point (i dont mean overboost) which will reduce the MAF reading too....all these values are part of the addaptive strategy and are intrerdependent
Click to expand...

I’ve disconected the snorkel (Mantec thing) and also the MAF as the tuners are adoment it’s not required. If it runs better then I’ll plug the maf back in as I’m sure it is needed (that’s not an invitation for people to start a war!:p)
 
With the snorkel disconnected I was getting an overboost fault (no limp mode, just the engine missing on hard acceleration). The highest MAP reading on a good hard run was 243.33kpa, at which point the AAP was 95.33 putting the boost limit at 237.33 (if that's correct). AAP reading at idle was 99.4, the actual pressure here is 102kpa (via a digital barometer).

Would removing the air filter make a difference?
 
Update: Much better with no air filter! surprise surprise, but not ideal (although it sounded lovely). I had a K&N air filter which I had previously removed due to reports of the oil in them knackering the MAF - well since I apparently don't need a MAF and its unplugged anyway I put it back in. The AAP now drops to 95 from 99, no overboosting. 99 is still 3kpa under the actual air pressure, but this may be due to the fact it's located inside the air filter housing? Although with the engine off and ignition on it was still only reading 99. I will try again with the MAF plugged in and see if that makes a difference, but it is very close to the 680kg/hr limit as it is.
 
That theory with K&N ruining the MAF is boll*x IMO... unless it was overoiled and even then that oil would not hurt a hot wire, it might ruin aftermarket MAFs cos as the air flow is better with it the hot wire is exposed to forced coolig for longer and a weak/cheap sensor can fail
 
sierrafery said:
That theory with K&N ruining the MAF is boll*x IMO... unless it was overoiled and even then that oil would not hurt a hot wire, it might ruin aftermarket MAFs cos as the air flow is better with it the hot wire is exposed to forced coolig for longer and a weak/cheap sensor can fail
Click to expand...

I agree, although I've never actually cleaned one! I've always just banged it on the floor a few times and put it back in :eek:

I will also try a different AAP sensor to see if it reads differently
 
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One thing I don't get which seems to get mentioned is that when the boost pressure on the gauge will increase, hover a bit then drop down as the wastegate opens. Not on mine, it goes up and stays there until you lift off the accelerator? I initially thought this was because my boost gauge runs off the inlet manifold, so I put an additional gauge on the wastegate but its the same, just reads slightly lower

Edit: bit of research this seems to occur on discovery’s with the modulator....
 
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So I gave it a blast this afternoon and I am still getting this overboost kangarooing! I didn’t have the Nanocom plugged in at the time unfortunately.

Could this be what they call “boost creep” ?
 
IMO that boost creep symptom is not valid for engines like the Td5 with electronic overboost protection managed by the ECU cos the boost can't rise so much to "overtake" the wastegate as the ECU cuts fuelling before that.
 
sierrafery said:
IMO that boost creep symptom is not valid for engines like the Td5 with electronic overboost protection managed by the ECU cos the boost can't rise so much to "overtake" the wastegate as the ECU cuts fuelling before that.
Click to expand...

Ok thanks. What is the point of these manual boost controllers if not to stop boost creep?
 
MBC is there to be able to adjust/raise the boost level untill below the overboost limit without messing with the wastegate cos it reduces the pressure to the valve so the wastegate rod can be more relaxed which gives a smoother boost curve
 
sierrafery said:
MBC is there to be able to adjust/raise the boost level untill below the overboost limit without messing with the wastegate cos it reduces the pressure to the valve so the wastegate rod can be more relaxed which gives a smoother boost curve
Click to expand...

Ok cheers, wasn’t sure if something like that was my problem. I suspect the AAP is faulty as it under reads by 3kpa. But I do see a lot of spiking in my Nanocom results generally for some reason, maybe that’s normal
 
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