Viano 3.0 CDi won't rev in gear

[GWhittell]

Hi,

Symptom: Engine revs fine in neutral, won't rev about 1000 rpm until the car starts to roll. Really low MPG in town. When flooring the the throttle with the foot brake (or with wheels against a kerb) thick black smoke wafts out of the exhaust. My feeling is that there is something preventing the air intake being able to match the fuel quantity being delivered hence the black smoke.

Having tried a couple of indies with no luck I decided to go to Mercedes last week which ended up being an infuriating experience which I won't bore you with! Anyway, I've bought a iCarsoft MB V2.0 and would like to know if some data I've captured identifies a possible issue?

For info on the iCarsoft the menu selection was :-
SPRINTER_EN_TEST_00004>VITO-VIANO Model designation 639 (OBDII)>VITO-VIANO (OBDII)>Diesel engine>Manual>CDI4 6 Cylinder>Actual values>Test engine at idle speed:

Engine speed ----- 674rpm
Idle speed stable ----- YES
B4/6 (Rail pressure sensor) ----- 259.36bar
Y74/1 (Pressure regulator valve) ----- 18%
Y94/1 (Quantity control valve) ----- 28%
Current injected quantity ----- 10.06mm³/Hub
Transmission neutral contact ----- NEUTRAL POSITION
B37/4 (Pedal value sensor) ----- 0%
B37/4 (Pedal value sensor) Sensor 1 ----- 0%
B37/4 (Pedal value sensor) Sensor 2 ----- 0%
B37/4 (Pedal value sensor) Kickdown ----- NOT OPERATED
M72 (Intake port shutoff actuator motor) ----- 80%
Atmospheric pressure ----- 1003hPa


What I've noticed is when I press the accelerator I get odd readings about the Pedal Value when the gear selector is in D or R (last two readings) :-

Engine Speed, Gear Selector B37/4 (Pedal value sensor), B37/4 Sensor 1, B37/4 Sensor 2,Throttle
674rpm, NEUTRAL, 0%, 0%, 0%, foot off
1064rpm, NEUTRAL, 11.32%, 11.17%, 10.90%
1935rpm, NEUTRAL, 18.32%, 17.94%, 18.11%
2892rpm, NEUTRAL, 19.16%, 19.16%, 19.07%
850rpm, Gear ENGAGED, 10.06%, 10.06%, 35.07% Part throttle
866rpm, Gear ENGAGED, 0%, 81.92%, 81.92% Floored

Before I go and buy a new pedal senor I thought I'd ask if these readings are unusual?

Also, I've had a look for some guidelines on what expected values are for the various sensors but haven't found very much. Just wondering if it's worth people posting data on a common post from working cars so that readers can see if a specific value is 'in range'.

Any help would be much appreciated as the car will have to go if I can't get this resolved, it's now my daily driver and 16 - 19mpg in town isn't viable!

Cheers!

 

[GWhittell]

Update, having driven the car this morning and monitored the three values whilst driving, I think the above anomaly was just a sampling error, all three values seem to track each other within 1 sampling rate.
If anyone is able to assist me identify and fix the issue or recommend a very knowledgeable indie near Leeds, west Yorkshire I'll gladly pay for a few packs of beers / a few bottles of wine / etc (as long as this doesn't break forum rules)

Just need to get this fixed before the Mrs calls time on the Viano and demands it to be sold as is

 

[GWhittell]

Having done some more monitoring of the parameters I noticed that the EGR position was always at 5%. I removed the plug, cleaned it with switch contact cleaner and reconnected. The EGR value is now changing and the car is running better but it’s still low on boost at low rpm. I guess the plug wasn’t seated correctly and some of the pins were not connected, strange how it didn’t throw a code or the EML.

I’ve also discovered that if I discovered that if I disconnect B28/1 (pressure sensor in the air box) the Y77/4 (boost pressure Positioner) moves over a wider range and I can hear the turbo working harder. The car is more responsive at low rpm but still not right.

When the B28/1 is disconnected I’ve noticed that most of the other values for the other pressure sensors drop in value, is this expected?

I’m more confident that it’s an electrical issue rather than a mechanical issue. I’ve sent the boost pressure Positioner now get as low as 10% so I’m hoping the turbo actuator is ok.

If any one can give some typical values for above sensors etc at idle, 1k, 2k, 3k rpm that would be much appreciated. And if possible cruising in 5th at above rpm (maybe not 3k as the police might not be too happy with you!)

Cheers....


07 Viano 3.0

 

[m80]

The EGR not functioning can block the DPF, apparently.
I haven't read all your posts but could restricted exhaust flow be worth considering.

 

[GWhittell]

Cheers for the reply.

I’m planning to remove the down pipe complete with the CAT to see if that’s restricted (the DPF was deleted when I bought it - not that I knew until I took it off to check it! the car had been running fine for a couple of years so it can’t be the DPF).

I have noticed the the exhaust back pressure sensor values vary massively when driving. At idle it is usually around the 1100 hpa mark and I have seen it as high as 3300 hpa when it’s near the redline. From my reading I think anything over 2000 hpa is considered to be high?

Also, the DPF differential reading is about 28 hpa with the engine switched off, I would have thought it should be 0 hpa. But, with the DPF being deleted I can’t imagine that sensor will be used any more but I could be wrong. I might swap it as a last resort.



07 Viano 3.0

 

[m80]

The turbo actuator, B77/4 can be tested in a simple way. When the key is turned the actuator performs a self test and travles through its range. For this I positioned a digi camera to film it as I turned the key, don't need to star the engine.

The barometric pressure sensor, post air filter, B28/1 I only have readings for when mine was faulty.
The change when revving was so small it surprised me 965 hpa was my reading. If I get chance I'll look at the 2.1 vito I've moved to. I gave up on the Viano as a daily driver it wasn't, and I needed one.

Average mpg expect 26mpg if driving gently,
best I've ever seen was 32mpg over close on 200 miles of very gentle driving.
16 - 19 around town doesn't surprise me, especially while warming up.

I'm with you on electriacl gremlins, mine had a few bad connections at sensors. This I found while testing from the ECU plugs through sensors when plugged in. I knew what to expect as I'd taking sensor readings at the sensors.
For that you need the drawings, and a lot of patience. But at least the warmer weather seems to be retuning, hopefully long enough to allow what's needed.

I now have a range of sensors that were replaced unneccasarily.
BTW iCarsoft (MB V2) led my on a few wild goose chases, you might find, as I did, that descriptions of a sensor can vary between pages, and even pressure sensors trying to read in centigrade.

 

[m80]

Have you considered the diagnostic app 'Torque'.
A free download, pay pro version available.
About £4 for a BT EML327 transmitter that will communicte with an Android device.

I have a 9" head unit and can monitor many things while driving.
The iCarsoft is a bit awkward to find support for, a phone cradle is common enough already for motors.

 

[GWhittell]

I have a BT ODB dongle already and I have the free Torque app. Can the Pro version read the MB specific codes? I’ve tried the Carly app too but it needs their dongle to do anything useful.


07 Viano 3.0

 

[m80]

I can understand why anyone would delete the DPF, but would be cautious of who I mention it to.
Some would have you dismembered for driving it that way.

Yes the back pressure looks high to me, with my limited knowledge,
my Viano 3.0 read 1100hps at 2.5k revs (that being sensor B18).

I would 'guess' that the DPF delete might remap static style readings to the ECU to trick it into thinking it's still there. Healthy readings meaning it doesn't call for a regen, not sure if there would be a pre test to overcome though.

Torque comes up with codes ok, but I just write any down and consult google where the app doesn't provide code info, which mine does often.
For 2 or 3 quids it's not wallet emptying and I use it often, it has also followed me to new devices and is installed on at least 3 right now. I'm happy I saved up and paid.

I might be worth dropping your empty DPF and looking up the cat with a torch, in case it has collapsed and blocked. That's a lot easier than dropping the downpipe.
Although if anyone deletes the DPF I would expect them to remove the cat also??