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corpi

Member Since: 01 Mar 2023
Location: 87440
Posts: 3

Puma 2.4 tdci NO boost

Sorry for the long post….
First a quick intro:
I am taking care of a 2007 Defender 130 station wagon for a sanctuary (Elephant) in south west France. This is my contribution to them.

I have read through several forum posts, most notably: [url]blackwolfs: 2007 2.4 loss of power, ideas?[/url] post

This time the problem is very little power. (Sometimes with a P299 code (less boost then expected)

I cleaned the MAP sensor, and it was fine for several months. (There was crud on the sensor)
After 4-5 months it happened again so I cleaned it once again. This time it came back a few days later and cleaning did not help any more. There where also NO error codes any more...
Time for more investigation:
- Replaced the MAP sensor made no change.
- I made an adaptor to be able to pressurise the circuit after the turbo, to check for leaks. And found a pretty serious leak between the junction of the EGR manifold and the inlet manifold. Found one of the tabs holding the 2 together was cracked, Replaced the inlet manifold. No more leaks. Yay!
Unfortunately still (almost) no boost (Flat out I could get about 0.2 bar boost).
Time to trawl forums …
I found the following places to look:
- clutch switch (would reduce power and give no code.) works as it should
- turbo VNT valves, sticky. Lever moves freely
- Turbo actuator – have no clue on how to test these (Google was NOT my friend this time)
I did open it up and tested the motor and checked the gears. All fine. I also tested the connection form the plug to the
PCB for continuity.
I then but it back together with the arm at roughly halfway point. Connected everything back up and with a few revs, I
had decent boost up to almost 1 bar before I chickened out.
- before replacing the actuator I tested the wiring from the plug the the plug on the ECU. All good…
- ordered an Ebay Actuator, with the same G number. Unfortunately still no change….
- I have NOT unwound all the wiring conduit across the engine yet. I am assuming that because there is continuity there should
be at least some movement from the actuators. But neither the old one or the new one have moved.

What am I missing?
Does anybody know what I can measure on the Actuator wiring? (I disconnected the ECU plugs when I measured continuity) Do the + and – pins on the plug carry 12v? When ignition is on? Or do the + and – power the motor and do the other wires give feedback telling the ECU the position?

Is there anything else I can I test?

Thanks for any help!

I am not familiar with the TDCI engine, I am happier with a TD5, and D2 in my case

1st Mar 2023 5:35pm

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 16857

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

Check the harness from actuator to ECM for chafing at any point where it is secured to or touches the engine. If an actuator wire is grounding on the engine it will pass your continuity test but the actuator won't work.

A harness fault is quite likely.

1st Mar 2023 5:43pm

corpi

Member Since: 01 Mar 2023
Location: 87440
Posts: 3

Thanks, looks like i have some unraveling to do...

I have lifted the loom from all places where it contacts any metal, and there are some chafing marks, but no where it done through the out sheathing.

Its a pity no one know what voltages oor frequenties to measure at the actuator plug ....

nor is it possible to quickly create a bypas loom to the ECU. as I dont want to cut the original wires before I know that that would give me a solution...

1st Mar 2023 10:29pm

corpi

Member Since: 01 Mar 2023
Location: 87440
Posts: 3

UPDATE,

I have unravelled the loom starting from the Turbo actuator. I almost missed the tiny dent in the insulation where the Aircon compressor support is, there was a slight copper flash as I moved the light.
Two tiny wear spots on one wire and some wear spots on another but NOT through. The outer sheath was worn, but not through, so the damaged wire could not short to the Aircon support.
There were no other wires where the insulation was worn through..... so how it was making contact anywhere... unless the sheathing was conducting?? its al dry!!

Anyway I supported the wires away from any metal ran the engine. There was boost!!!

so obviously the cause found. THANKS for the tip!!

I cut the wires, also the damaged but not worn through one, and but some heat-shrink on before soldering them back together again..
Went for an actual test drive before taping the loop back. all good.

Now the sanctuary can use the Defender again, and I have learnt a new skill: taping up a loom

3rd Mar 2023 5:09pm

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 16857

Excellent, glad you are sorted. The Puma engine harness is something of a disaster, and I am constantly surprised how (relatively) rare vehicle fires are. Mine came very, very close to self-destruction, with exposed copper due to to chafing on the live feed from alternator to battery (the one "protected" by the megafuse). To this day I don't understand why my vehicle hadn't become a fireball.

3rd Mar 2023 7:29pm

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