Thread: D2a TD5 loses power at WOT on hills

Originally Posted by LOVEMYRANGIE

When not actuated, bottom port should be blocked with flow from side to top port.

Bottom pipe to turbo pressure
Side pipe to actuator
Top pipe to turbo inlet pipe.

You can't test it as its pulse modulated but if you can blow thru any other combinations when it's unplugged, it's stuffed.
Not expensive to replace and can be picked up for around $40.

Part number PMK100130

Cheers
Andrew


Sent from my backyard TeePee using smoke signals.

Well, that's interesting as mine is the opposite - it is currently removed off the vehicle and I can blow through the bottom port to the side port. The top port is blocked!

Bottom pipe to turbo pressure
Side pipe to actuator
Top pipe to turbo inlet pipe.

With it disconnected I can blow through it from side pipe (actuator) to bottom pipe (turbo pressure) and the reverse.
However, the top pipe (turbo inlet pipe) is blocked and cannot be blown through.



Uploaded with ImageShack.us

the modulator (black thing) is brand new.. the actuator (silver thing on the turbo) has not been changed

I have been advised by the previous owner that the modulator is actually brand new and has been changed. As you can see from the following pictures it looks new and shinny:



Uploaded with ImageShack.us


Uploaded with ImageShack.us


The actuator looks like it may have also been changed at some point, it has hand writing on it, although as you can see from the quote above by the previous owner obviously not by him:



Uploaded with ImageShack.us


I have removed the actuator and using some compressed air blown into it, it moves which indicates to me that it's probably functioning alright.

it sounds like its going into over boost, the modulator has never been replaced. ide check how much boost its making first and then adjust the mod back a touch so its not making too much boost, or buy a boost box from BAS in the uk.
there was a thread on aulro about a modified MAF bypass hose, its to allow air past the maf so it wont go into a fault setting. this could be an issue due to the mods done and the new head work?

The other thought by the previous owner above. I intend to do some further reading on these options.

The writing on the wastegate actuator is the pressure setting in bar ie 1.309bar is 19psi measured at the turbo. Actual manifold pressure would be like 16-17psi.
If you have a very good pressure reg on your compressor, turn it all the way to 0 connect a hose to the nozzle and connect to actuator and very slowly wind up the pressure on compressor reg until
You get close to 1.1 bar.
Put your finger on the actuator arm and slowly tweak it until the reg hits 1.3 and you should feel it move.
I reset mine to 1.45 bar by shortening the rod which now gives me 20psi at the manifold.

The thing is when driving these is that foot to the floor really won't achieve much particularly in an auto and also due to the fact being diesel, it only has a certain torque range so it may well be a need to modify your pedal habit. Having come from 20 years of various high power petrol turbos and lots of V8's, I really had to modify how I use my right foot.

In an auto much over 3500rpm will start to slip the convertor and grunt is lost.

Cheers

Ansrww


Sent from my backyard TeePee using smoke signals.

I did some playing and testing with the modulator this afternoon. When it is connected to a 12v source, the top (turbo inlet) and side ports (actuator) are connected and air is able to freely flow from one to the other.
With no voltage on it, as stated earlier, side pipe (actuator) to bottom pipe (turbo pressure) are connected.
When the ignition is on, the modulator receives 12v.

I then drove the vehicle with the wiring loom for the modulator disconnected - this is basically in effect bypassing the modulator, the car performed as per usual, with no noticeable loss in power.

I believe therefore that my modulator is functioning correctly and that my issue lies elsewhere.


A new symptom appeared yesterday and reoccured today.
Basically yesterday comming up a hill in a 100km/h zone from stand still start at the base, the car performed well and pulled hard, but in 2nd gear, the engine rev to approximately 4,400rpm, and then cut in and out - like brooom, cut and nothing for a second, brooom, cut and nothing for a second, repeat (my father was in the car with me, he thought I was actually taking my foot on and off the accelerator and being an idiot). This is very similair to what happens on other cars when they hit the rev limiter - i.e. a fuel cut.
Today this occured again, however, this time I think it happened in 3rd gear (may have been second however, as I wasn't concentrating too hard or counting) and happened this time at around 3,900rpm. I believe 3,900rpm is too low to be the red line and so don't think this was the rev cut out. This also occured on a hill.
This is making me wonder more about fuel issue with the vehicle. The fuel filter is reasonably new, despite some off road driving it is still clean and in good condition, but I intend to replace it now anyhow.

Any other ideas?

Max torque is at 1950 rpm and as Lovemyrangie said,reving the ring -gear out of it is a waste of time and money!,anything over 3000rpm is overdoing it my opinion,let alone 4000,mine rarely sees 2800rpm,but Im an old truckie used to changing gears at 1200-1500!,let the donk work like a diesel and you'll be much happier(or buy a sports car)
Cheers Gregg

Originally Posted by 3-Gees

Max torque is at 1950 rpm and as Lovemyrangie said,reving the ring -gear out of it is a waste of time and money!,anything over 3000rpm is overdoing it my opinion,let alone 4000,mine rarely sees 2800rpm,but Im an old truckie used to changing gears at 1200-1500!,let the donk work like a diesel and you'll be much happier(or buy a sports car)
Cheers Gregg

Yeah mate, that is great advice to apply when driving the vehicle, but at the moment the vehicle is having issues, so reving it the full way up is part of the testing process to try to work out where the issue is coming from. Regardless of where the engine makes it's power, if it can't rev all the way up and is doing funny stuff in the higher revs then it's likely an indicator of an issue.
I appreciate the comments on how to drive my rig normally, but at the moment while it's bumming out when being normally driving on the hills it doesn't quiet apply...
Maximum power of the TD5 as fitted to a 2003 Land Rover Discovery HSE TD5 is 101kw at 4,200rpm. Clearly there is an issue then if my engine is not willing to rev up to this point.
It is also automatic, so the flash point on the automatic transmission when taking off is around 2,200rpm and it should change the gears at the points that the Land Rover developers deemed to be optimum (debatable).
I have a medium rigid truck licence. I have driven a variety of diesel powered vehicles from passenger cars to MR trucks. And this Disco engine is not happy and not behaving itself on the hills, it's not my driving that's causing that, it's a fault somewhere in the engine that I intend to rectify.

I have been following this thread with some interest, as I had similar problems with my V8 when I first got it.
It turned out that the plastic air intake duct, after the MAF, had slid off the manifold. This was virtually unnoticeable until I brushed my elbow across it, and it moved. Once placed back on and clip tightened, all was good.
My point is that I would not be too quick to discount a problem with the MAF/air intake, even if you have replaced it.
The other thing that springs to mind is the fuel pump.
P.S. You must be in line for the quickest ever to 100 posts.

Originally Posted by biggin

I have been following this thread with some interest, as I had similar problems with my V8 when I first got it.
It turned out that the plastic air intake duct, after the MAF, had slid off the manifold. This was virtually unnoticeable until I brushed my elbow across it, and it moved. Once placed back on and clip tightened, all was good.
My point is that I would not be too quick to discount a problem with the MAF/air intake, even if you have replaced it.

I have checked all the post turbo piping and they are all good. The joiners are fairly new silicone units (which are better than the factory rubber ones).
The preturbo pipe (from MAF/airbox to turbo inlet) I had off yesterday and checked and refitted.
The MAF I still need to check. I probably need to organise access to a testbook/nanocom/doovlacydevicethingo to do so though.

The other thing that springs to mind is the fuel pump.

Agreed. It is certainly something that I need to check.