New MAF time

[LostKiwi]

When looking at pressure sensors you need to know if they are absolute or relative readings. An absolute reading is relative to 0 bar (MAP sensor for example) whereas relative readings are compared to atmospheric (or some other reference point). An example of a relative reading is a boost gauge.
Looking at those values suggests they are absolute values though 977 is a shade low (I'd expect 990 to 1035).

 

[M80]

Still at this little issue.

I saw the exhaust back pressure was between 850hpa and 1100hpa, depending on revs. A read up tells me that is way too high.

DPF differential pressure between 55 - 300hpa, againd Google says that's way too high.

That would suggest a blocked DPF.

I've just removed the DPF and with a torch the front mesh looks mucky but certainly not blocked. I'm guessing that the true filter is behind and out of sight though.
The exhaust back pressure is still reading 850 - 1100 though.

I'm now looking at removing the KAT, but if the back pressure isn't too high as Google says I might find nothing and a replacement DPF might be all that's needed??

Any thoughts?

 

[Dogfish]

M80, Nightmare.

My advice is tell her "It's all a little intense right now and explain how you need to take a break".
Then disconnect her battery.


Put it on charge even if you don't think it needs it for at least 24 hours on a low charge.

Before you pull the power do a final full test of each section using icarsoft diagnose, test and clear. , assuming the signals and fault codes are constant, make a photographic record of what icarsoft says.. Then write each one down and sort them out starting with fault area control box then the code then description given. Further sort into major sub sections, ie body codes -B, powertrain =P...

Meanwhile clean all the earth points; could help clean up the signal over the can between control boxed, ecu, and other noisey electrical mush. There must be about 28 to 30 earth points I'd assume, but who knows? May help.
Dont forget the lights, heavy engine and transmission earths and the battery terminals and the posts; Just to be thorough and cover the electrical 'noise' and backgrount mushtheory basics.

With any luck, after 24 hours the control boxes will all have nodded off to sleep, the ram memory (?) will exhaust and they all get 'amnesia'.

Reconnect the +ve first.
Then -ve.

Go through the specific reset adaptations for the vito, I dont know if yours has adaptation..Ya know, the reset windows, sunroof, cannons, and reset the transmission, the Odometer codes. Everything.

Redo the I casrsoft photo record, and compare with the notes done previously.

Just to see if its the same or anything has altered. I'd also clear and reset the icarsoft codes left over.

Just a thought...or plain rambling?

Anyways, good luck. The truth is out there.

 

[M80]

I have found a lead to follow.
The MAF has had its 12 volt feed picked up from the fuse rail, rather than the ECU as should be.
I have downloaded wiring diagrams, but these are for the earlier 639 and don't include the 642 engine as is fitted from 2005.
As expected many wire colours are different but more importantly the pin outs from the ECU are different so identifying the MAF
12 volt feed from the ECU isn't possible.

I am thinking that the ECU is the problem, and I have found an ECU in Latvia, but an ECU only and it looks like this particular ECU is rare. It is suggestd that these units are reprogrammable, if not it's as good as a brick as the EIS and other components won't communicate.
If I'm very lucky being able to trace the MAF fed and identify that issue might be all that is needed, but I haven't felt lucky so far.

My thinking, although likely a bit wild, is that the 12 volt feed is for the hot film within the MAF. Now that the feed is bypassing the ECU it doesn't see that hot film load and so generates a fault code??
I'm not sure if this may be related but is it possible that who ever did this pulled the pre turbo heater to compensate some how?
If I'm anywhere close with this theory the wiring needs to be rectified for a new ECU anyway or the code will still be present.

What I'm hoping from you good people is,
a) to be directed to a relevant 639.815 witring diagram that includes the 642 engine,

b) thoughts on the reprogramming of the available pre loved ECU to match and communicate with the EIS, cluster and other matched units.

 

[M80]

Oh,
the wiring diagram I have is "Wiring Diagram Manuals Part Number: Z6517 2111 02"

There are plenty of sites offering a download for a nominal fee (not always nominal) but when checked it's for the same wiring diagram and my money would have gone bye bye.

 

[M80]

Still at it (rearange the four letters as felt appropriate), me and the van.

I wanted to give up long ago but local Indies say they can't fit the van on their ramps. A recommendation of a commercial outfit that don't even list MB's on their site doesn't have appeal.
MB Macclesield, or their subcontractor, I think would have replaced the MAF again (£307 +labour and diagnostics), the MAP sensor again. Before running up a bill and suggestion the ECU is at fault.

With the correct drawings I've worked through all sorts.
All is wired correctly, no modifications.
Bad conection at sensors has been a problem.
This being from over worked connector pins, probes opening them or what??
Checking wire continuity, and insulation from other wires isn't an issue. Checking good connections at ECU and then sensors not so straight forward.

Where I'm at now is the MAF is connecting at both ends (it wasn't at the MAF). Now it has the heater connected the flow readings are 13.5 - 48g/s. W/o star I can't know if that is within range but the iCarsoft still reports P0101 'out of range' code, now the only code. Won't reset.

EGR and shut off motor both stay at low reading (5% ish), but I'm assuming that is effect not cause. They are connecting and motors look to be good.

Fuel rail pressure sensor had an issue with connection but now ranges from 25,700Kpa to 77,000Kpa. I did actually check for good fuel flow from the filter output (trying for anything and everything), there is plenty flowing.

The charge pressure sensor (B5/1) stays at 800hpa, plugged in or unplugged.
I've confirmed good connections at ECU and sensor.

Could this cause the MAF range fault, or is the MAF needing adapatation and that a red herring?
Is the lack of charge pressure recognition, within the ECU I assume, enough to hold off turbo boost and my lack of power?

 

[Glynn350]

My experience with what I think was a faulty/dirty MAF (cleaned the MAF with electrical contact cleaner and symptoms went away), are that the car doesn't start in limp mode, but goes into limp mode while driving, and turning the car off resets it. My reading also suggested that disconnecting the MAF's will not necessarily result in limp mode either, just less than optimal running.

Could there be an issue with the turbo itself?

Another small thought: When I pulled the MAF's off the turbo intake, I found the orange seal hadn't been seated properly on the turbo at the bottom of the seal, which also may have contributed to my limp mode, worth a check.
When I pulled mine off there was a dint/bend in the seal where that part of the seal had been pushed into the turbo intake, rather that over it, perhaps causing an air leak after the MAF. I guess that would mean there would be less air going into the intake than the MAF was telling the ECU that there should have been?

 

[M80]

Thanks for the thoughts.
2 new MAF's to eliminate a faulty new MAF, doubtful but well. Multi metrer readings taken from the new MAF prior to instal was the same as the other 2.
Might be worth a new seal later, the air filter has been on /off so mant times.

Tomorrow I intend to check again that the air route isn't restricted, then the exhaust. That will include passage both ways through the turbo, that spins freely.

None of that would explain the lack of recognition of the charge pressure sensor, but looking at the history of this that was reading a few weeks ago, strange.


I have decided that I need star.
Nothing would have identified the bad connections other than the multim meter method I used.
But, while I agree with Alistair, iCarsoft is just about ok to carry in the back it has too many little issues to be a reliable diagnostic tool for the 639.
It describes pressure and reads in centigrade, on another page that little fopar is correct.
After resetting on the OBD section it hadn't reset faults in the diagnostics.

To see if actuators are performing and not just moving I need star.
To see if sensors are operating within parameters I need star.

In short I don't have confidence in iCarsoft, or the support of the seller. It does more than the very basic Torque pro, but that is prety good for a quick view.

 

[M80]

So midday my Star arrived.
It does take a little understanding and familiarisation.

I have just been for a drive up steep hills with loads of power.

I remember Steve Avant Garde's suggesting a reset of MAF adaptations so I did.
A test run and as I turned to go up hill a little screech from the rear tyres as I applied power, yip oh, power deon again, not as bad and no MIL.

Back to Star, I saw that it was telling me that EZS needed sychronising. There was a faultwith the coding, 'Do I wish to code EZS'.
I'm out of my comfort zone there knowing that this unit can do tricky things, so I was returning here ot ask for opinion on if I should allow it to.

But before doing that I went through the process of clearing all codes on each unit that had them to see if any returned, bearing in mind over the last 13 weeks all sorts have been removed, replaced unplugged... and a new battery along the way.
Codes went, but I 'think' there may be issues holding the DPF regen from doing so.
Anyway, fingers crossed, it feels like I have a motor again,
and a diagnostics kit that can interrogate properly.