Help with Overboosting TD5

Hi all,

Long time and all but..... I need help...]

My 04 TD5 D2 has started playing up. It did this once before years ago and changing the wastegate modulator fixed it but not this time. All is usually fine but at wide open throttle it seems to over fuel and kangaroo. It does not go into limp home mode.
I have attached some screenshots from nanocom data.


I have checked the waste gate and it moves VERY freely
The waste gate actuator moves smoothly
There are only 11 threads showing between the lock nut and vacuum end of the bar (however it has worked fine like this)
I have bypassed the waste gate modulator (like a defender)

Can someone explain what these plots are actually showing? can I increase the resolution?

The nanocom plots are just me driving round the block occasionally using full throttle, would there be a better way to make a plot? better things to plot?

I do notice in the instrument section, Turbo Pressure (Bar) showed 0 all the time...???

I look forward to any help, suggestions and thank those that do in advance.

MAF and or MAP are dead.

The MAF should read around 60 at idle.

Check what the manifold inlet temp is too

Any fault codes?

Hi Bankz

This is at idle and I assume it includes MAF (airflow) MAP (Manifold Turbo Pressure) AAP (Ambient pressure) and air inlet temp. Are they what you were after?

I also assume that MAF comes from the hot wire between the air box and turbo, MAP comes from the plenum just before the runners into the ports, AAP comes from the sensor in the top of the air box as does inlet air temp. Is this all correct??
can these sensors be tested, cleaned etc. or are you shore there knackered and I just need to change them and go from there?

Any other readings of use? I will go and check, clear drive and check again for fault codes now. Ten min...….

Thanks again...….

So, my nanocom has stopped communicating with ether of my cars, nothing at all.

I just updated the software and all works fine with pc but nothing with obd cable.

I just emailed nanocom now for a solution.

Hence, no fault codes as yet......

Leon. said:

I have checked the waste gate and it moves VERY freely
The waste gate actuator moves smoothly

Click to expand...

I don't understand you saying that the wastegate moves very freely.
My understanding of the device is that there's a strong spring in the vacuum chamber and to get it to move when doing static tests you need to grip the actuating pin pretty tightly with say, a pair of "mole grips" and when I tried to move the pin on my Td5 it took both hands to push the pin.
While it moved "freely" with regards to it not binding or sticking, I wouldn't say that it moved "very freely".

Sorry for the misunderstanding, a few definitions - as I see it, please correct me if im wrong -
Waste gate; part of the turbo that releases pressure (the little leaver sticking out the turbo)
Waste gate actuator; Vacuum chamber (in this case) that mechanically operates the waste gate (the diaphragm, spring and adjustable rod)
Waste gate modulator; Electronic device (in this case) that controls the amount and timing of vacuum to the waste gate actuator. (solenoid with three vacuum pipes on the disco, in this case deleted as defender setup)

So in my problem, with the actuator and gate separated from one another, the gate moves very freely and the actuator, although tough, moves smoothly.

hopefully that is clearer??

That sounds about right. Wastegate sounds normal from what you describe.

Try unplugging the MAF go for a drive and see. If it drives better MAFs dead, drives worse MAP could be dead. On the Nanocom go to gauges, go for a drive and see if the boost level changes as you drive. If it stays at 00 the MAP is dead. The MAF - Air Flow (gr/hr) should read around 60

There is also a test you can do with a voltmeter.

Im little gutted my NANOCOM has stopped playing when connected to obd so no codes.... but

I tried unplugging the MAF after the NANOCOM stopped (old fashioned testing) and it appeared to drive worse.

On gauges (instruments) the boost level (turbo pres.(bar)) read ether 0 or -0.01 when driving.
At idle MAF was between 61.2 and 64. so how close is 'around 60..??

Would a dead map cause this kangarooing only at WOT and 3K+rpm?

Thanks again all.

Ok that means a very healthy MAF (mine reads 54, think I need new one) but a dead MAP.

Try cleaning the MAP sensor with brake cleaner and try again. If nothing changes time for a new MAP sensor.

Take it easy driving till you change it.

Tried cleaning so a new sensor will be ordered.

Is there a consensus regarding the manufacturer of said sensor? must it come in a land rover box, are bosch ones ok, how about the cheep ones you see...????

Lr or bosch.

Leon. said:

how about the cheep ones you see...????

Click to expand...

buy only branded MAP, it's too important to mess with cheap sh*t