Discovery td5 under powered (towing)?

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nickbdk

New Member
Posts
9
Hi all!

well i just got a 1999 D2 td5 last week and iv done fuel air and oil filters, man gearbox oil, rear diff oil, cam cover gasket, FPR, and fixed the oil leak on the new oil cooler.

When driving without a trailer on it seems very slow compared to my 2001 2.5TD l200.

I had a 2T - 2.5T trailer and load on monday and did 173 miles with the load on and what can i say!! WHERE IS THE POWER! As soon as i hit a hill that was it! 5th 4th and on long hills 3rd!

Is this normal? it just seems to not have any power when reving. It doesn't like to rev over say 3k, the engine doesnt sound happy if you know what i mean! Im a mechanic so im handy with spanners!
 
As you're a mechanic you'll know it could be loads of things from fuel supply to bla bla bla.

I would get the MAF function checked out first to see if it's delivering the proper signals to the ECU. You'll need T4, Nanocom or Hawkeye for that.


Dave
 
Maf,map,wastegate control valve.cacky egr.crank sensor.check for oil red plug at ecu.
mine absolutely stonks up hills even with the caravan on.recently flat as a witches tit. already done de egr,new wastgate control valve so i removed crank sensor,it was filthy with crap all over it hadnt got an Oring to seal it plug connector was full of oil.new one fotted and she is back to full tilt.
 
Thanks for the reply! I will have a good look at it and see. I just didn't know if that was the normal speed for a td5, it seem quite a heavy 4x4. As it's a 5 cylinder if it's missing can you tell as well as a 4 cylinder missing? Need to find someone near me who can plug it in for me cheap as the works reader can't even read why the amber ACE light is on.
 
A cheap check you can do is to disconnect the Maf,these often slowly die giving a very low output.Disconnecting forces the ecu to use a default value,should restore most,if not all of the power.
 
I keep hearing this "disconnect your MAF and it'll improve things" comment and I just don't understand it.

MAF's don't degrade over time. They are electrical components that either work or they don't - no degradation - on or off.

When they stop working they give no output. A 5volt signal is sent from the ECU and a faulty MAF doesn't modify it at all. As a result the ECU defaults to a pre programmed set of parameters.

If you unplug the MAF the ECU still receives no signal so it defaults exactly as above.

Bearing that in mind, if you have a faulty MAF plugged or unplugged will make no difference to how the ECU calibrates fuelling.

Dave
 
thebiglad said:
I keep hearing this "disconnect your MAF and it'll improve things" comment and I just don't understand it.

MAF's don't degrade over time. They are electrical components that either work or they don't - no degradation - on or off.

When they stop working they give no output. A 5volt signal is sent from the ECU and a faulty MAF doesn't modify it at all. As a result the ECU defaults to a pre programmed set of parameters.

If you unplug the MAF the ECU still receives no signal so it defaults exactly as above.

Bearing that in mind, if you have a faulty MAF plugged or unplugged will make no difference to how the ECU calibrates fuelling.

Dave
Click to expand...
Well 10 years of using T4 on literally hundreds of TD5's tells me a different story.Maybe I should refund all those garages and individual owners my diagnostic fee ?
Experience has shown it to best to drive each car on a standard route to get a feel for how they run or to experience the owners issue.It takes seconds to disconnect the Maf whilst doing the test run,and often points me in the right direction before hooking up Testbook.The standard values I'm happy with are 55-65KG at idle and 330KG or more at 3000rpm running free.When the maf's die I often see figures of 35 - 40 and 260-280.This results in a very flat power output.
 
Well had it on the works solus pro and air flow kg/h at tick over is 48-50.7
At 3k still is 270-280

At tick over

Barometric pressure kpa 94.9
Map kpa 95.2

What do you think?
 
My MAF was slowly dying too - I replaced it 2-3 weeks ago and normal performance has been restored. The degradation is slow and can go unnoticed until one day you think 'I used to storm up this slope, whats going on?!'

My MAF readings before were 32 at idle and 300-320 at WOT (wide open throttle). According to my LR specialist, these figures should be around 60 at idle and 600 WOT. Fitted a new MAF and voila! An easy test is to disconnect the MAF as suggested ^^^. If it runs better with it disconnected, its pretty good proof that the MAF is not sending accurate readings back to the ECU.

Your readings seem low to me, and I'd also recommend renewing the MAF. The aftermarket ones last 1-2 years and the genuine ones 3-4 so its up to you whether you want to fit a pattern at £30 odd or a genuine (Siemens) one at £70 odd.

Alternatively you could try cleaning the MAF sensor with electrical contact cleaner. This is basically an aerosol solvent which degreases the sensor and evaporates off very quickly. Do NOT be tempted to try and touch the sensor with anything - it is VERY delicate and that little blade sensor snaps at the slightest excuse. I know because I've broken two - the second one knowing how delicate they are, so I was being extra extra careful. The bugger still snapped. be warned ;)

HTH
 
Put a new MAF on and the reading are higher, tick over is now 59-60 and at 3k is now 360 ish, also cleaned the boost sensor as it was FULL of oily gunk. It pulls a bit better but not as much as it should I don't think. I'm thinking I my need a new boost sensor it did look very bad when It came out. I'm going to try and see what it's boosting up to peak, can anyone tell me what it should be boosting at?
Think there is a problem there still some where! I do have a soft spot for a Landy but they to test your patients some time! :confused:
 
cambridgecockney said:
Maf,map,wastegate control valve.cacky egr.crank sensor.check for oil red plug at ecu.
mine absolutely stonks up hills even with the caravan on.recently flat as a witches tit. already done de egr,new wastgate control valve so i removed crank sensor,it was filthy with crap all over it hadnt got an Oring to seal it plug connector was full of oil.new one fotted and she is back to full tilt.
Click to expand...

What does having oil at the red plug of the engine ecu indicate?
 
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