Defender TD5 lacking power at speed

[T.Paasch]

Hi all.

I have a Defender TD5 from 2001, which I've had for half a year now. (2 years earlier I had a 1999 TD5 for 4 years). My car starts perfectly every time, pulls nicely when it's cold, but when the engine is at normal running temperature, it lacks power and kind off cuts out briefly when accelerating onto the motorway or when driving up a hill at speed, where it needs to pull.

To me it feels like it's either not getting enough fuel, or it's getting the wrong mix.

On my way home from the used car dealer where I bought it, the fuel pump suddenly started whining quite loud.

So first I checked with the dealer, and he send me documentation that the fuel pump was just replaced 1 month before I bought the car with a VDO pump - so it should be OK.

I then changed the fuel filter and the blender and the return valve and ran the bleeding procedure a few times. This actually helped on the whining sound. I still think it's a little more noisy than my previous Defender but it's not too bad. But still some thing doesn't seem quite right, as the pump goes on pumping for 30 seconds when I turn on the ignition. But the car starts perfectly when I crank it as soon as the glow lamp turns off.

Next thing I checked the MAF, that had been changed as well just before I bought the car. I got out the voltmeter and checked that the MAF gets power, no problem there. Then I checked the MAF output which was around 2V at idel and increasing when the throttle is down - so that seams ok as well. Finally I checked that the cable between the MAF and the ECU is OK, and that was fine as well.

Then I took out the MAP sensor and cleaned that. It was quite filthy, but cleaning that didn't help either.

The Injector harness was also replaced by the dealer when I bought the car, due to the usual oil being pushed through the harness. I cleaned the ECU connectors with contact cleaner spray and even opened the ECU to check if any oil had entered, which luckily wasn't the case.

I'm running out of ideas. 
Unfortunately I don't have the means to check if the fuel pressure is right.

Does anybody have any ideas what I could try to troubleshoot the problem? Any input is appreciated.

Regards Thomas

 

[Tanuki]

The 'noisy fuel pump and poor running' sounds very similar to the symptoms for failed copper injector-seals, which let bubbles of combustion gases get into the fuel-rail and cause intermittent flow of Diesel to the injectors.

What distance has the car covered?

I would expect the seals to need replacing after something like 70,000 miles/110,000KM.

[T.Paasch]

Hi Tanuki
Thanks for your input.

It has run 138.000 km so far, so that could be it. I just checked it out on YouTube and that doesn't look like a DIY job for me. Is there a way to verify that that is the problem? What I found so far this should also cause higher oil level in the engine and also cause starting problems (which I don't have at all).

 

[paime]

Does it feel like a misfire when the engine is under load? Mine used to feel like i'd hit a wall when i was going up a hill at 50mph+ or sometimes i couldn't even get to 50mph and it turned out to be a stuck wastegate actuator. It's very easy to check if this is causing a problem, just remove the circlip and pin from the rod end of the actuator and see if you can easily move the lever on top of the turbo. Mine needed copious amounts of WD40 and a slight nudge with a hammer to free it up but it instantly cured my problems.

Here's a video on it: 

 

[Souster]

+1 on the waste gate actuator. Had the same on mine. Also double check red ECU plug under the seat.

[Escape]

I also thought about the wastegate, but that would have the car pull strongly and then cut out (hitting a wall as @paime says) as the boost gets too high and the ECU cuts fueling. Still worth a check, as it's not much work. I'd also try to get a reading of boost pressure when accelerating. If it's not building full boost, the lack of power will become obvious at higher speed. The hoses to and from the intercooler are known to fail, usually causing a loud whistling when revving.

Filip

[T.Paasch]

Hi Paime

Thanks for the tip. I’ll check that out after Christmas and let you know. 

 

[T.Paasch]

I have now checked the waist gate. I basically did like in this video: https://youtu.be/fS3ZfUsXOs8

After removing the actuator I could easily move the lever, but it didn’t move back by itself. I drowned it in WD40 and worked it until it did and reassembled everything again.

I just had a 40 km test drive on the highway and testing some of the up hill junctions where it usually is coughing , and so far it fells like there surely is an improvement. No more coughing and it did 130 km/h like it’s supposed to do.

So thanks a lot for the tip Paime!!!

 

[paime]

Anytime! Hope the wagon keeps going well!

[Lightning]

Great news that you found the fault, and it was something straightforward.