Desperately need some help interpreting these Diagbox/Lexia live data graphs...Help!

[Mervyn44]

Hi everyone. I have a 2007 Citroen C4 Picasso 1.6 Hdi (110).

The car starts immediately every time and idles reliably but it is not smooth (you can feel slight vibration in the cabin and through the pedal). Upon pressing the pedal it hesitates and takes on a juddery "running on 3 cylinders" feel as it accellerates through the rev range until around 2500rpm, at which point it appears to sort itself out! When driving the roughness is less apparent but there is very low power until around 2500rpm when the turbo comes in... then it pulls like a train!

I have gathered lots of live data but am unsure how to read it, some of the values definitely look a bit suspicious to me (turbo position, EGR valve data (a new one was fitted shortly before I bought the car), injection main advance... and injector number 2 certainly can't be normal!).

Talking about injectors, the codes were all programmed to the wrong injectors when I checked them, suggesting someone had been swapping them round but hadn't updated the coding. I have now done this, it did seem to improve things slightly but the problem is still largely the same. I also swapped injectors 2 and 3 to rule out an actual injector fault but the weird injector value stays on cylinder 2!

There are no error codes being logged and no warning lights on the dash, the global test comes back clear... although communication errors are shown for various ECU'S, but I've no idea if this is significant/related.

I will post the global test report below. Many thanks for reading... car was bought for my terminally ill father and has now been off the road for 3 months... just can't afford to spend any more on it.

Any and all help enormously appreciated! Many thanks - Merv.

[Mervyn44]

Global test results :


Version of the copy : 3.27.01 Date and time : 2017-05-13 16:10:10

Tool information
Tool serial no. L3-AG197
Serial no. VCI 011113
Type of VCI V4.3.2
DiagBox version : 07.57

Info PDV
Code RRDI :
Company name:
Profile RA
Technician's name

Vehicle info
Type of vehicle C4 PICASSO
Vehicle Layout C4 PICASSO
VIN: VF7UD9HZC45167885
BUILD CODE NUMBER / RPO
Mileage 151814
Vehicle identification
Date and time : 2017-05-13 16:10:10
Make : CITROEN
Name : C4 PICASSO
Architecture : C4 PICASSO
Automatic reading or manual entering of VIN : : AUTO
VIN : VF7UD9HZC45167885
ITEM_DIAG
Date and time : 2017-05-13 16:10:30
Global test :
Date and time : 2017-05-13 16:12:15
ECUs present
BMF : Built-in Systems Interface (BSI)
Response data
R61809664058780002C96640587800501FFFF064052114799
R61B1941804800100000220212C0202
R61BA0200000000000000

State of the ECU: BSI
Reference 1 : 9664058780
Reference 2 :
Faults present : 0
ABRASR : ABS/traction control
Response data
R6180966093458000039660934580FFFFFFFF2001FFFFFF00

State of the ECU: ESP81
Reference 1 : 9660934580
Reference 2 :
Faults present : 0
AIRBAG : driver and passenger airbags
Response data
R61809646864780000E966421798008060000034046595399

State of the ECU: SAC_AUTOLIV
Reference 1 : 9664217980
Reference 2 :
Faults present : 0
AUTORADIO : Radio or radiotelephone (radio part)
Response data
R61809653789477000496646223774200000004404726369A

State of the ECU: AUTORADIO
Reference 1 : 9664622377
Reference 2 :
Faults present : 0
BSM : Engine relay unit
Response data
R618B964380218000139664055680060EFFFFFFFFFFFFFFFF

State of the ECU: BSM
Reference 1 : 9664055680
Reference 2 :
Faults present : 0
COMBINE : instrument panel
Response data
R61809653868980002C9664365280081C0810004056726399

State of the ECU: COMBINE
Reference 1 : 9664365280
Reference 2 :
Faults present : 0
DIRECTN : Power steering electric pump unit
Response data
R61809684252580000F9684252580060060050F01FFFFFFFF

State of the ECU: GEP
Reference 1 : 9684252580
Reference 2 :
Faults present : 0
HDC : ECU at the top of the steering column
Response data
R61809648164077000696642551770530060002405051529A

State of the ECU: VCCF
Reference 1 : 9664255177
Reference 2 :
Faults present : 0
INJ : injection/ignition
Response data
R61FE00000000032F0C070701A00701070B08FE0003A702653 697

State of the ECU: EDC16C3
Reference 1 : 653697
Reference 2 :
Faults present : 0
PADDITIVATION : diesel additive adding pump
Response data
R61D79658411580

State of the ECU: PADDGO
Reference 1 : 9658411580
Reference 2 :
Faults present : 0
PORTEC : driver's door electronics
Response data
R618096824955800035968249578001040002014051985999

State of the ECU: EDPC
Reference 1 : 9682495780
Reference 2 :
Faults present : 0
PORTEP : passenger door electronics
Response data
R618096824955800035968249588001040002014051985999

State of the ECU: EDPP
Reference 1 : 9682495880
Reference 2 :
Faults present : 0
ESSUIV : windscreen wiper
Response data
R61D09654063380

State of the ECU: MOTEV
Reference 1 : 9654063380
Reference 2 :
Faults present : 0
FSE : Electric secondary brake
Response data
R61FE00000000035E050A060001C172050A06FE00000001640 504

State of the ECU: FSE
Reference 1 : 640504
Reference 2 :
Faults present : 0
BOITEVIT :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
COMELBVA :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
SPNEU :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
ADDITIVATION :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
DSG :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
CORPRO :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
BECB :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
STL :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
BSR : Trailer relay unit
Response data
R618D00000000000000000000000000000000000000000000

State of the ECU: BSR
Reference 1 : 0000000000
Reference 2 :
Faults present : 0
AAS :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
CLIM :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
BCD :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
AMPLHIFI :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
CHANGEURCD :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
TELEMAT :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
KML :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
DMTC :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
ALARMES :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
BDMC :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
BPL :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
CPL :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
RHF :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :
MDS :
Response data

State of the ECU: communication error
Reference 1 :
Reference 2 :
Faults present :

[lurossi]

Hello, I interpret that fault as a leak of vacuum in the admission or a bad closing of the egr as well as bad connection of empty connection hoses turbo,Do not forget to change diesel filter, greetings

[Mervyn44]

Many thanks indeed for those suggestions Lurossi, can I ask what leads you to those suspicions?

I will test for air leaks in the induction system and report back, I will also change the diesel filter asap.... as far as I know its not the easiest of tasks on these engines!

[autoden]

I suspect the EGR especially if after market. Blank it off and road test. It will put eml on but you can clear that later.

[rideon]

Time to get dirty...
Start with compression test...

[Mervyn44]

Thanks guys...

Compressions tests come back fine. Can't find any evidence of air leaks either.

Being suspicious about the EGR throttle and copy readings in those graphs I decided to disconnect it as its right there on the air metering unit at the front of the engine... it put on the EML but had zero effect on running. Blanking the EGR sounds like a logical next step so I'll try that next.

When you look at those graphs I posted, you can see how the data relates to engine speed. Several things don't make sense to me...

1, turbo pressure etc seems to be responding but turbo position is stuck at 100% while turbo reference position (which I assume is what the ECU considers normal) hovers around 50%. If you watch the turbo wastegate valve while the engine is being revved, it hardly moves, if at all! - is this abnormal or is just because the car is in neutral and not under load? Although the car is extremely underpowered and just bogs down at low revs, it does take off like a rocket when you get above 2500rpm on the road.

2, Injector circuit on cylinder 2 stuck at +6 permanently. This could be an ECU or wiring fault although I was told by somebody elsewhere that they also had this problem (caused by an injector coding issue), apparently with no ill effects! I've also heard that the total for all cylinders when added up should be around zero, but mine is far higher than that (assuming the value on the graph is accurate) which would indicate significant over fuelling?

3, the main injection advance seems to abruptly plummet when the revs approach 3000rpm. I wonder if this is normal or might explain why the car suddenly regains power at around this point? Up until now I had assumed that this was just down to the turbo kicking in?

4, lastly... the camshaft/crankshaft sensor graph is just a flatline at zero. Is this just because it is always in correct alignment and therefore fine?

[lurossi]

Hi, I suspect because of the unstable engine at low rpm, a revised injector return? And pump additives,
And also hoses in and out of turbo, intercooler, absolute pressure sensor, etc..greetings

[Mervyn44]

OK, I have checked the induction system for leaks, the plastic pipe from the turbo to the air metering box/unit had a really tiny leak underneath. This has been repaired and I think (I think) it has improved the idle smoothness a little. The engine still seems a bit rough to me (it jiggles back and forward as it runs), not sure how normal this is.

Power is still extremely weak until the turbo kicks in (no puling power at all unless I keep the rpm's above 2500-3000). there is also a hesitation in acceleration although this doesn't seem quite as bad now.

I've also tested the wiring harness for continuity back to the ECU and this checks out fine.

I have ordered an EGR blanking plate and understand that a faulty EGR will cause my symptoms... but I just can't see how this would cause the bad readings only on cylinder 2!

As stated, compression tests are fine, Injectors have been swapped and the problem stays on cylinder 2... with the wiring now also eliminated the only other thing I can think of is the ECU itself? Another person is convinced it is an injector seal leak but there is no signs of this (no puffing or vapours). listening with a screwdriver all the injectors sound largely the same. When I removed the injectors the nozzles and the shafts (the long cylindrical part that sits inside the head between the lower copper and upper plastic seals) were covered in diesel... I can't understand why diesel would be om the shafts, There is no diesel above the plastic seal on the top of the head. I would love somebody to explain this... one of the injectors in question is new.

[Mervyn44]

Lurossi, you mentioned fuel additives. What was the significance of this?

I have no error codes and no warning lights are lit but in the global test there is red text which says something like... fuel additives... communication error.

Also, if you look at my global test printout above there are loads of ECU's which are listed as "Comunication error", is this important? Everything else in the car appears to work fine so I was thinking this maybe related to features that were not installed in my car?

[Mervyn44]

I suspect the EGR especially if after market. Blank it off and road test. It will put eml on but you can clear that later.

Fitted EGR blanking plate (it did not illuminate the EML), also replaced fuel filter and checked injector wiring harness for continuity (all good).

The car actually seems worse now. It knocks a lot and seems particularly rough and under powered under load now so I will probably remove the blanking plate again.

One strange noise has returned since this work, an intermittent clacking sound at idle. It sounds a little like somebody tapping on an empty paint tin. It goes clack, clack...nothing...clack...nothing...clack, clack, clack as the engine idles, pretty random! Its hard to pinpoint but is not coming from the injectors, it sounds like more towards the rear centre of the engine (towards the bulkhead) closer to the flywheel than the timing end. I'm wondering if this could be a valve issue on cylinder No.2 (maybe sticking?) or to do with the camshafts? This would explain the weird diagnostic injector readings for cylinder 2 although I have been told that compression tests came back as normal.

Would really appreciate some speculative input from anybody watching this thread as the car has now been off the road 4 months and was bought for my terminally ill father. I could maybe record a video of the car running and driving and upload it to YouTube if anybody thinks that would help.

Sincere thanks as always - Mervyn.

[kanon]

.....One strange noise has returned since this work, an intermittent clacking sound at idle. ..........

.... that is the Dual Mass Flywheel.

All this is very similar to the problem with timing (belt, chain, ......).

[Mervyn44]

Yes, I've eliminated virtually everything now. The only other thing that makes sense is a timing or compression fault... or a faulty ECU.

I've been told by two people that compression is good (the guy that sold the car and my own mechanic) but its got to the stage now that I can't help being suspicious so I'm hoping to test again myself tomorrow rather than take somebody's word for it.

I also need to find out if there is an easy way to verify the timing is right without dismantling half the engine. I had assumed the crank/cam sensors would have thrown up a fault if anything was off?

[autoden]

Does it have a dual mass flywheel as kanon asks?

[Mervyn44]

I'm reasonably sure it has yes... and sure enough the noise is consistent with what I've been googling about DMF failure... although there is no signs of problems while driving.

I'm prepared to accept this noise may indeed be the DMF, although I don't see how that would be related to my original problem.

Many thanks for your input by the way guys, I really appreciate any help I can get!