Alan C · Feb 4, 2009

04 TD4 Freelander with lack of power from 1800 revs or so. Starts and
idles fine. Foot flat to the floor from 1800 revs or so and it'll get
to 2000 and pretty much stay there unless the auto box kicks down.
Acceleration is very poor. No fault codes and no MIL light,
diagnostics all show all engine sensors are operating correctly.
Capturing to an avi file on a drive shows nothing abnormal. I've
checked all vacuum hoses and replaced suspects, and replaced squishy
turbo hoses. Disconnecting the MAF the car drives fine, so replaced
it, but still no cure. As car drives fine with disconnected MAF, I'd
guess this rules out a fuel problem. Any further ideas? I have a Boost
Control Valve on order, so will change this next. Is there anywhere
else I should be looking? If the Boost Control valve was faulty,
wouldn't the manifold presure go very high? There's no EGR valve to
worry about either, it's been removed with a bypass kit. The rocker box PCV filter has also been changed.

I'm stuck!

Alan C

bonnybrook · Feb 4, 2009

Was th MAF replaced with a geniune LR one?

Shropshire Hippo · Feb 4, 2009

Hi Alan , my symptomes exactly , all hoses changed and checked , new genuine MAF , fuel filter , fuel pump , rocker thingy filter , air filter and still the same . As you when MAF disconected runs fine . Got a chap coming tomorrow whos a auto spark and supposed to be very good , If he sorts it out I'll post his findings tomorrow night . Mine was dieing at 70 but tonight coming home from work it couldn't get above 45 .

atvb Paul.

Alan C · Feb 4, 2009

The replacement MAF is a new and genuine LR item. I also have a Pierberg MAF and Synergy unit, but they've been removed to eliminate them. The diagnostics (BlackBox Solutions Faultmate MSV) confirms all monitored sensors and presures are within correct limits. I've been reading Shropshire-Hippo's posts with avid interest as it seems the exact same fault. I await your auto sparks diagnosis with bated breath!

Alan C

Shropshire Hippo · Feb 5, 2009

Hi Alan , snow realy coming down here (day off work , no time to be taking somones roof off !) so don,t know if sparks will make it today . Don't hold your breath too long , he may not come today

atvb Paul.

Alan C · Feb 5, 2009

Just a quick update. I've just replaced the fuel filter in the rear O/S wheel arch (what a stupid, stupid design for a service item location, really enjoyed doing that with snow on the ground in icy conditions, not!). As expected, didn't make any difference to the running of the engine. Last thing is the Boost Control Solenoid, hopefully have one tomorrow. More fun.

Alan C

Shropshire Hippo · Feb 5, 2009

Hi Alan , just got in from a great afternoon holding things for mr sparks

Very thorough and although can't be 100% sure , there is a fault with the boost control solenoid and boost pressure came up as a fault . Clear fault and runs for a short distance and then limp home mode cuts in again . won't get part till next week so will wait with baited breath to see if yours is fixed with the solenoid ! also a bit of oil in the air intake getting passed the turbo , not a lot , is this normal ? he muttered somthing about seal in turbo on the way out but by this time was too cold to care anymore

Chaser · Feb 5, 2009

A bit of oil in the intake hoses and intercooler is normal on most turbo diesels including td4s. It comes from the crankcase breather in 99% of cases. Just make sure it's kept to a minimum by changing the engine breather filter on the top of the cam cover.

ming · Feb 5, 2009

cough. . . . . .sounds like one fuel pump gone weak to me , wont show on diagnostics till it gets werser. . . . . . . . . . . . .i'll get ma coat

Alan C · Feb 5, 2009

I certainly wouldn't rule this out, but doesn't explain why the car runs almost perfectly with the MAF disconnected? Would have thought that would about rule out a fault with the fueling?

Alan C

Shropshire Hippo · Feb 5, 2009

Chaser said:
A bit of oil in the intake hoses and intercooler is normal on most turbo diesels including td4s. It comes from the crankcase breather in 99% of cases. Just make sure it's kept to a minimum by changing the engine breather filter on the top of the cam cover.

I love youuuu ! could well do without a turbo going ! ever have one of those spells when nothing goes right ? in two months have spent over £2000 on cars and a vans repairs

need some luck now .

atvb Paul.

ming · Feb 5, 2009

Alan C said:
I certainly wouldn't rule this out, but doesn't explain why the car runs almost perfectly with the MAF disconnected? Would have thought that would about rule out a fault with the fueling?

Alan C

Sorry i missed that bit . . . . .your correct

Chaser · Feb 6, 2009

Alan C said:
I certainly wouldn't rule this out, but doesn't explain why the car runs almost perfectly with the MAF disconnected? Would have thought that would about rule out a fault with the fueling?

Alan C

But when the disconnection of the maf sensor triggers the ecu to use a default map does that help the situation even if the fault is elsewhere??

Alan C · Feb 6, 2009

With the MAF disconnected, and presumably the ECU then runs on a default map, the engine runs almost perfectly. Can't leave it like this though, the fuel consumption is drastic, and I don't want to damage anything, plus the MIL comes on.

Land Rover main dealer phoned, no parts delivery today, due to health and safety all the truck drivers at LR have been instructed not to drive. Hopefully the solenoid will be in for Monday.

Alan C

Chaser · Feb 6, 2009

Alan C said:
With the MAF disconnected, and presumably the ECU then runs on a default map, the engine runs almost perfectly. Can't leave it like this though, the fuel consumption is drastic, and I don't want to damage anything, plus the MIL comes on.
Alan C

Agreed, i'm just thinking that the effect of disconnecting the maf may not prove that the fuel system or anything else is without fault.

Alan C · Feb 6, 2009

Plus to unplug the MAF connector, the air filter cover has to be removed first, it's a right pig to get it to line back up again to bolt on, so have left it off while testing, can drive about like this, but wouldn't be very funny if my K&N air filter jumped out and run the car on unfiltered air especially as there's so much slush, water grit and salt flying about at the mo!

Alan C

Alan C · Feb 7, 2009

The boost control solenoid arrived this morning, bolted it on, easy to do. No change, the fault is still there. Hmmm, what to do? Dealer suggested the high pressure fuel sensor in the end of the fuel rail, but diagnostics show this is working fine. Else it's change the turbo? No way to easily test it either? Poo. :-(

Alan C

ratty · Feb 7, 2009

Alan C said:
The boost control solenoid arrived this morning, bolted it on, easy to do. No change, the fault is still there. Hmmm, what to do? Dealer suggested the high pressure fuel sensor in the end of the fuel rail, but diagnostics show this is working fine. Else it's change the turbo? No way to easily test it either? Poo. :-(

Alan C

Alan. Have a look at the sensor anyway. The connection is renowned for going green or brown. Take it off, clean it and see if that cures it.

Also if you look on the front chassis rail for the fuel feed and return pipes you will see a connector on one of the pipes. Take it off. If it runs fine with it off your rear fuel pump is weak. If it makes no difference it's ok.

Shropshire Hippo · Feb 7, 2009

High Alan , gutted for you mate and feeling less confidant that it is going to sort mine out now

Having said that I was there when he plugged the puter in and boost pressure fault came up so fingers crossed . When he took it off and tested it it wasn't behaving as it should so he said it was worth a try as when he fitted a manual pump which he operated while I drove around he could adjust it to get the power back . Though at times I thought it started to die but wasn't sure if it was him or another fault

. We shall see ,starting to get very expensive !

atvb Paul.

Alan C · Feb 7, 2009

The high presure fuel sensor contacts are nice and clean, double checked them anyway. I was sure they were as I'd had a Synergy unit plugged in which connects there and I had checked the contacts were clean as a matter of course. Will check the low presure fuel pump pressure sender trick tomorrow. The low presure fuel supply was giving a reading of about 310 KPa at tickover, the diagnostics help files says it should be about 420KPa, also the fuel presure regulator was drawing 0.5 amp, the manual says should be about 1 amp at idle. Also noticed today that from idle, pull off from standstill and power seems to be about normal, and will rev past 2000, let it change gear (it's auto), come back to idle then won't rev above 2000 and feels very low on engine power. Come to a standstill, and then pull off, power is back then repeats as above. Does all this add up to a weak pump? Not too hard to change it, just gotta get that stupid assembly out the rear wheel arch again! And another fist full of notes.

Alan C

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