Technical Help with P023761 Turbocharger Control Negative drift (High Pressure) Signal Calculation failure

[rallyman1984]

Hello Fellow Fiat Forumer's

I've been helping a close friend try and sort his 2017 Fiat Ducato 2.3 JTD SWB Van out. (113,000 miles)

During the cold snap, it wouldn't start until it was well above 5'c.
He said it was glow plugs, and hence 4 new NGK glow plugs went in, despite me telling him they all checked out (as did the diagnostic machine) Ok.
anyway, Done a leak off test, and it needed injectors, 2 really bad, 1 ok, and 1 good. So stuck 4 in it, and now it starts as it should with minimal cranking.

THE remaining problem. (which its always done, even before the injectors/non starting in the cold)
Under FULL heavy throttle (really really loaded, or towing) , it lets a sudden "jerk" which it throws itself into limp mode, and then engine light and a massive lack of power.
The only code keeps coming back when it does this is "P023761 - Turbocharger Control Negative Drift (High Pressure) - Signal Calculation failure."

I've checked the vacuum hoses, all look spot on (haven't been as far as the actuator yet tho) all look ok.
boost pipes all look good and doesn't appear to be any splits etc.
it goes like **** off a shovel, as apparently its been mapped and EGR mapped out (unsure if its blanked or not) by previous owner(s)

Could it be a chafed wire ? Map Sensor ? Boost Solenoid ?
seen loads online of underboost faults but not found any overboost faults.

any help, pointers or "id check this" would be greatly appreciated as its a cracking van, but such an annoying niggling problem.

 

[theoneandonly]

Which engine is it 130 or 150/180. different turbos. could be sticking actuator or vanes if vvt. p0236 (on its own) normally points to turbo solenoid valve. not seen 237. what are the freeze frame details?

 

[rallyman1984]

Which engine is it 130 or 150/180. different turbos. could be sticking actuator or vanes if vvt. p0236 (on its own) normally points to turbo solenoid valve. not seen 237. what are the freeze frame details?

Hi @theoneandonly Thanks for your prompt reply !!

It's the 130 2.3 JTD (Iveco unit i believe)

I will get it to fault again tomorrow and log the freeze frame on here. Much appreciated any help

I have to admit, it does seem to chuck a bit of black smoke when revved, even at a stand still. BUT, as mentioned, I think the DPF is out of it, and the EGR Mapped out. Both by a previous owner to the current owner. Van drives perfect if you dont REALLY REALLY welly it. But the moment you try and really clog it up a hill or pulling a trailer it does this.

 

[rallyman1984]

Which engine is it 130 or 150/180. different turbos. could be sticking actuator or vanes if vvt. p0236 (on its own) normally points to turbo solenoid valve. not seen 237. what are the freeze frame details?

If the vanes were sticking, you wouldn't expect it to go as well as it does, ?? surely it would be a bit sluggish ?

 

[theoneandonly]

If the vanes were sticking, you wouldn't expect it to go as well as it does, ?? surely it would be a bit sluggish ?

I was thinking your explanation could be sticking at extreame of travel and then causing too much boost. ie sticking at full boost not low boost and not increasing (had that on a Audi A4)

 

[rallyman1984]

I was thinking your explanation could be sticking at extreame of travel and then causing too much boost. ie sticking at full boost not low boost and not increasing (had that on a Audi A4)

Good Point ! I was also reading could be faulty wiring from MAP sensor, !? going to check the loom tomorrow. Although you would think it would throw a code up for MAP if that was the case. Going to check the 5v supply to it tomorrow.

 

[theoneandonly]

wide open throttle tests with VCDS

I did a wide open throttle test on my VRS yesterday (accelerate in 3rd from approx. 2000rpm to red line) and this is a graph showing the results I got: the pattern seems a bit alarming to me as I've got this one from the hidden-power website that shows what a standard graph should look like and m...

www.briskoda.net

have a read , it suggests both stuck turbo and MAP sensor.
If you have got Multiecuscan i would suggest a wide open throtlle pull. a test measuring turbo boost actual and required 2nd or 3rd gear running at idle the plant it full throtle and then snap off. (also measure rpm and turbo control positions)
VCDS rosstech.com is a good source of info and suggestions. I used it to prove my A4 turbo was dead.

 

[rallyman1984]

wide open throttle tests with VCDS

I did a wide open throttle test on my VRS yesterday (accelerate in 3rd from approx. 2000rpm to red line) and this is a graph showing the results I got: the pattern seems a bit alarming to me as I've got this one from the hidden-power website that shows what a standard graph should look like and m...

www.briskoda.net

have a read , it suggests both stuck turbo and MAP sensor.
If you have got Multiecuscan i would suggest a wide open throtlle pull. a test measuring turbo boost actual and required 2nd or 3rd gear running at idle the plant it full throtle and then snap off. (also measure rpm and turbo control positions)
VCDS rosstech.com is a good source of info and suggestions. I used it to prove my A4 turbo was dead.

@theoneandonly. Thank you for your help so far.

Here I have attached a couple of videos of the recording of the data. Also a video of it revving in neutral. (seems to be a lot of black smoke)
The Air Mass Meter was replaced not so long ago with a genuine Bosch unit by current owner (my close friend) and hence I think that can be ruled out.

It seems the Recorded Boost is somewhat slightly higher than the "target" boost. I'm wondering if it could well be a MAP sensor / (and or its wiring) or Actuator/ (and or its Wiring) fault.

Your opinion ? anyone elses opinion ?
the van is mapped and DPF' deleted and EGR Deleted, it seems absolutely RAPID but this sudden jerk and limp mode is so frustrating.

After these videos, down hill it went like stink and didnt fault, so clearly is when its pulling hard and full boost the issue arrives.

Overboost 1 Video.

Overboost 2nd time (right at start of video)

Smoke on rev (Neutral)

 

[theoneandonly]

Have you got a graph of the first one or even a saved file ( txt or csv) to create a gaph from.
Graphs easier to read. The MAP sensor when too cloged become more rigid and dont respo d to pressure changes quickly. They can be cleaned with carb cleaner but literature says use more expensive map cleaner because of contaminants. I would use carb cleaner £5 or replace the MAP £40 but ive got both in shed stock

Looking at vid 5th time if a vvt it is not stuck closed. It is possiblty stickjng at top end and a dose of turbo clean wont go amiss. Please confirm it is not a 130

 

[rallyman1984]

Have you got a graph of the first one or even a saved file ( txt or csv) to create a gaph from.
Graphs easier to read. The MAP sensor when too cloged become more rigid and dont respo d to pressure changes quickly. They can be cleaned with carb cleaner but literature says use more expensive map cleaner because of contaminants. I would use carb cleaner £5 or replace the MAP £40 but ive got both in shed stock

Looking at vid 5th time if a vvt it is not stuck closed. It is possiblty stickjng at top end and a dose of turbo clean wont go amiss. Please confirm it is not a 130

Hi theoneandonly.

It is a 130bhp, and after looking underneath today I'm thinking its a Non VNT, and its just a normal wastegate.
It does however look very rusty, and im thinking it could be stuck shut. Not to mention, on the live data, the air mass is "above" the target, so im thinking its stuck closed.

However, it looks like you would need arms and hands like two pieces of string to be able to get to the actuator/rod !!
difficult enough just to see it, let alone get the rod off the arm and work the arm.

Will report back tomorrow.