[Stefan96]

It's me again! This time with a vehicle that isn't my own, but a friends: 2006 XC70 D5 185 hp (D5244 T4)

The problem: The car significantly lacks power, so much so that it does 0-85 km/h in approximately 3.5 years
No warning lights or error codes besides an ECM-7700 and no smoking as well.
The problem is, that the vehicle is heavily modified: DPF delete, EGR software delete, swirl flap delete and a following optimisation by one of the previous owners, which I assume is causing the code and why that code doesn't throw a check engine light.
The boost pressure values seem normal. Air mass flow might be normal or a bit low, depending on which source you decide to trust. (If anybody has concrete values, please do share!)

The first guess was a leaking intercooler, which was in fact true, but a new intercooler didn't change anything.
I tried just about every reset that the Biltema diagnostic tool will let me, with no effect of course.

Next we will try to build a smoker and check the entire intake system for leaks, but about 30 visual inspections didn't show anything.
Besides that I'll have another look at the fuel pressure and put a camera in the engine bay to check if the actuation of the VNT works (although I'd suspect that it wouldn't make much boost if that wasn't working, no?).
Same deal with the intake pipe, just to make sure that's not collapsing under the negative pressure difference. It seemed fine upon inspection by feel, but might as well...

I also just read tonight that a faulty O2 or DPF temperature sensor can sometimes cause a lack of power with no CEL, so I need to check if the diagnostic tool lets me stream those values and check the sensor wiring.
If you have any more ideas what else to check, please let me know! I'm not a diesel guy...

Thanks for your help in advance!
- Stefan

[Stefan96]

Update:
I just found a not insignificant leak at the swirl flap arm. It seems like the "swirl flap delete" was that someone simply removed the linkage & arm of the flaps and left the flaps flapping in the breeze...
Why and how much that leaks is a bit surprising to be honest, but oh well...
I guess that means the injectors & manifold is gonna come off. I'll report back if that fixes the problem once the kit gets here and it's installed.

- Stefan

[Stefan96]

Update 2:
Installing the kit failed miserably so far, due to 4 injectors not budging at all, and of course one can't pull the intake manifold off without removing the injectors. Brilliant design
Tried every trick in the book, except a pneumatic hammer because we don't have one, all without success. Unfortunately my slide hammer doesn't have an adapter that could thread on to the injectors and the clamps didn't help.
If anybody knows the thread dimensions on these injectors that would be of great help - that way I could try to make an adapter.
We will keep soaking the area it with whatever I can find and hope it eventually makes its way down the injectors. Recommendations regarding this would be welcome since I somewhat doubt carb cleaner or WD40 will cut it.

- Stefan

[Stefan96]

Update 3:
2 new injectors and a lot of money later the kit is installed - and it of course didn't fix the problem, but at least the intake leak is fixed.
I checked the entire intake system again for more leaks, but it didn't seem like there were any.
All the sensors still show more or less reasonable values, so I still think all they are okay, but who knows. I can of course try to unplug some of them and see if it changes anything, but I suspect that it would only send the car into limp mode, if it isn't already.
Regarding that: Does anybody have a source on how they behave in limp mode? I only found a couple posts and one video that were all inconsistent. The car will do 80 km/h, but it takes a very long time to get there. Acceleration at low speed seems fine, but then completely drops off at around 30 to 40 km/h or so. Again, no error codes or warning lights, but someone possible tempered with that...

- Stefan

[Stefan96]

Update 4:
Found someone with a DiCE and VDASH and flashed a completely stock map on the car. That resulted in the dash lighting up like a Christmas tree, so apparently one of the previous owner had found a very creative way of hiding every possible error code. TCA, engine mount, glow plug and multiple EGR codes, which led to a whole new search. Found a blown fuse (the one for the EGR valve, turbo control actuator, engine mount vacuum valve etc.), replaced that and it blew again right away. That led to another search, which led to the EGR valve control board having apparently developed a short. Tested the valve itself (the motor etc.) and got a new control board, and checked all connections from the board to the ECM of course.
When powering the car up (or just the EGR valve circuit) the EGR does the movement check to close itself, so the new board etc. works fine and the EGR position sensor error code (ECM-4450) also went away. All the other non-EGR codes were of course just related to the fuse being blown.
But the EGR valve error (ECM-4430) together with "Engine service required ASAP" message remains, no matter what we try. Deleting it doesn't help, it comes right back on the next power cycle. Even flashing an EGR delete tune with VDASH instead of the stock map doesn't make it disappear (in case anyone is considering trying that, just don't.).
I assume this error is what is keeping the car in limp mode. Is there any procedure that I'm missing to make the car relearn that it has a functioning EGR? Since all everything seems to work fine I'm once again out of ideas.

- Stefan