New Owner. low down power Problem TD4

Hi All

recently picked up a 2005 TD4 to use for the wife's horse trailer and general useful hack.

Was running spot on when i got it. Did some investigating and bought an EGR bypass. Fitted it and when i drove the car, had lost lowdown power, didn;t get anything below about 2000 when it spooled up and drove fine. Checked fitment and all seemed OK, but decided to refit EGR. Still got the same lack of low down power.

I'm thinking i must have disturbed something, but can.t work out what. I removed the intake as far as airbox and return. There is a small sensor to the front left ( looking from front ), which i assumed at first was the MAF, but it isn't. I'm wonderimng what this sensor is, this seems to be teh only electrical sensor i've touched.

Anyone had this problem, or does anyone have any advice. Having trawled t'internet a couple of posts suggest a low pressure turbo vane solenoid?

Any help much appreciated

Thanks

There is a small sensor to the front left ( looking from front )

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on top .. just forward of the oil filler cap ? .. no far from the maf ?
think that might be the camshaft sensor ..
if so .. when that goes faulty .. symptom be hard-to-start-when-hot
that sensor is used by the ecu for startup only .. afaik ..
i.e. won't have anything to do with low power under 2k rpm

as far as the mystery sensor is concerned ..
might be best to post a pic so it can be identified ..

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get anything below about 2000 when it spooled up and drove fine

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turbo should take effect around 1200 rpm and above ..

maybe check the small filter on the back left of the engine ..
the one that looks like a plastic / paper element in-line petrol fuel filter
and it's open ( not connected ) at one end ..
if that gets clogged up .. the vacuum operated turbo vanes will not work properly

lack of power under 2k rpm is often connected to the maf sensor ( as well )

ROVER 75 MGZT ENGINE FAULT FINDING

Maf sensor problems.

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about the td4 ( freelander mk1 vehicles ) :
http://www.rover-club.net/graphics/manuals/16/m47r_diesel.pdf

basics of common-rail diesels :
http://www.yildiz.edu.tr/~oisin/Dersler/Dersnotlari/0653611/dinjection.pdf
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if you've got the egr delete .. best to keep it installed ..
fitting one should not detract from low end power ..

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also .. might be best to start off by checking and cleaning All the electrical connections
to the various engine sensors and injectors .. and then smearing some 'contralube' on
the connector pins/spades ..
that way you can almost eliminate a faulty connection .. and save having probs. in the future
td4 suffers somewhat from water ingress ( check the oil filler plastic dish after heavy rain )
which ends up coroding sensor/injector wiring .. if left unchecked ..
the hp rail-pressure sensor is particularly prone for some reason ..

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bought an EGR bypass. Fitted it and when i drove the car, had lost lowdown power, didn;t get anything below about 2000 when it spooled up and drove fine

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wondering if you didn't accidently dislodge something that maybe was loose in the first place
like a vacuum hose .. or an electrical connector ..

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btw : solution may not turn out to be any of the above ..
off hand can't think what else might cause under 2k rpm low power ..
maybe the fuel rail pressure sensor ??
( don't know If that would do it .. but is known to produce a variety of symptoms if faulty ..
( and that connector is in the region of the egr gizmo ..

Thanks for the feedback, i'll check the filter at the back left.

I think i may have disturbed something, but it could just be a coincidence that its happened then.

I've ( hopefully) attached a picture with the sensor i'm referring to highlighted, its in the air intake system, would normally assume its the MAF except i've learnt on here thats under the air cover at the back...

If this has happened since you fiddled with the EGR then check the pipework to the EGR. Its small-bore vacuum hose is plumbed into the lines from the vacuum pump that also feed the brake servo and the turbo VNT actuator.
If you didnt blank it off thoroughly when you bypassed the egr, or if the ends of the hose are split and perished as many tend to be as they get older you will have a vacuum leak that may prevent the turbo VNT mechanism operating properly.

Thats great, its a good point to start. Where is the turbo VNT mechanism?

Thanks for all the help

I've ( hopefully) attached a picture with the sensor i'm referring to highlighted

Click to expand...

oh .. that one

that's an air-temp sensor ..

one of LZ's hippo td4 experts had an issue with that recently
here's their thread :
http://www.landyzone.co.uk/lz/f9/td4-air-flow-meter-203545.html

it does get oiled up from sitting in the intercooler hosing ..
( some oil there is normal )

i usualy .. ( if i have reason to dismantle those hoses ) ..
will clean it with 'gunk' ( google it ) .. and then spray it with alchohol cleaner ( from maplins )
easy to do with the sensor still attached to it's housing ..
( just be careful of the wiring )

if it's kaput .. a new one is not expensive ..
if it's faulty .. the ecu will default the reading to -5C ..
resulting with ovefueling ( at higher air post-intercooler temps )

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btw: re. td4 (bmw) water ingress issue .. .. injector harness / electrical connections aside ..

somewhat off-topic .. .. but .. ..

there have been the rare odd horror stories of snapped crankshafts .. ( bmw and rovers )
i think usually at higher milage .. ( 100k plus )
One theory put forward was water-in-the-oil-sump ..
( as there be other theorys / reasons why that could happen to some cranks )

water can collect around that oil-filler-cap-dish after heavy rain ..
and it would only take an ill fitting oil cap / faulty cap seal to allow some water in ..
( the filler head being about level with the dish top )
in order to eliminate that possibilty .. i drilled three small holes ..
at 9-o-clock when looking at it from front of car ..
that should allow collected water to drain .. away from any electrical connectors ..
( i.e. so the level never reaches the oil filler top to start with )

just a suggestion is all

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'n this product will evidently use water as a 'carrier' ( as well as oil )
ZX1 Home
i've used it in the engine oil / power steering / engine coolant
( to no ill effect so far .. after 11k miles of use )

Where is the turbo VNT mechanism?

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it'll look similar to this ( pic )



'n a vacuum hose will be somehow connected to the actuator

great, i'll start working my way through that list. I just "feel" that its something in the air intake, the way its driving and the fact it was ok before i started "fettling"

I'll do some checking and dismantling and put the EGR bypass back on and see what happens !

hd3 said:

it'll look similar to this ( pic )

'n a vacuum hose will be somehow connected to the actuator

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Nice picture of the turbo etc thanks hd3.

From that it looks like the vacuum actuator works the VNT direct via the rod. I wasn't sure as I thought I read about checking the VNT by applying 12v to the actuator, meaning the vacuum servo tells the electrical actuator what to do, and by a suitable system of linkages and electrons it already knows what you're thinking! Now it's completely clear thanks.

fizgig good luck with your troubleshooting.

Quick update. Folloing the advice on here (thanks all) I have replaced the EGR bypass and checked its all sound and have replaced the Boost solenoid. But still no difference.

I tested the actuator works (this feels like the root of the problem) With the vacuum pipe disconnected, there is no movement on the arm, with the hose connected there is a small amount of movement, maybe 7mm as we accelerate from tickover to about 2000 rpm. This seems a small amount of movement, does anyone know how far it should move, does this means my vanes are sticking or is this the right amount of movement?

I'm getting desperate, still no power under 2000 rpm but absolutely fine after this, its making it hard to drive as when you hit roundabouts yuou have no power and can;t quite get into first ( i don;t like the wife being in this situation).

Can't seem to see any vacuum issues so completely lost. Mate has a local garage, but they are stumped too, but they are no LR or Diesel experts !

Help... :-(