2009 906 633 313CDI with OM646 2 Stage Turbo Engine
Initially this Sprinter had bad starting, lots of cranking needed, the guy kept driving it with EML on, it gradually started losing power until very sluggish then I got it to fix after others had given up
I use MB Star, SDS, (DAS on this model)
Initially it had MAF, EGT Sensor, O2 Sensor and EGR Codes.
I started "round 1 (ding ding)" by replacing MAF, EGT and 02 Sensors, also an Air Filter, all Genuine MB Parts. I did the teach in process for MAF and Air Filter.
It would not allow me to do a DPF Regen at this stage due to constantly flagging EGR code, 2355-002 EGR Rate too high, which I had on "Round 1" so I replaced EGR Motor / Valve Assy, again Genuine MB as "Round 2".
I cleared the Codes then got it to Regen DPF successfully, after which it drove much better power wise.
It now gave the "Air Flow Offset Drift" Code so onto "Round 3"
So far this Van has had a new quality Battery, a new MAF, new EGR, new Lambda, and new EGT Sensor, also new Air Filter just in case...............
The DPF Regen made it pull a lot better but only for about 30 miles, then I cleared codes that had come back, (Air Flow Offset Drift and EGR rate too high), and I did another Regen, drove better again after that. See * below.
It is also still needing a lot of Cranking to fire up, worse when it's part warmed up, despite Injectors passing a Leak off test, they were replaced by another reputable Diesel Specialist Garage last year, and were also coded correctly.
It has decent Rail Pressure when Cranking from Cold, gets up to ~265 bar within a couple or 3 seconds but doesn't actually start firing for at least 15 - 20 Seconds, then stops firing, switch off, re Glow, crank again and it's firing within a few seconds and gradually fires up and starts after about 10 - 15 seconds.
Very recently it has also had a Fuel Quantity Valve and a Fuel Temp Sensor in the Main Pump, which was also checked for the "loose bolts syndrome", all MB Parts and all to no avail..............
It is still hard to start, and a bit down on Power, worse when codes come back and it goes into in limp
, actually right now, "fecked if I know"
I dropped the Downpipe at the Turbo today, it was still a cow to start, I am currently comparing Air Flow etc Data from Exhaust attached on / Exhaust Off at Turbo Joint.
EGR, Throttle Valve, Both Turbo Actators, Pre Glow and EGR, Throttle Butterfly etc all pass DAS Actuation Tests.
Only Data that is reading bad is Air Flow on Idle, it is at ~510 mg/Hub and DAS is saying it should be around 380 mg/Hub, plus DAS says on Idle EGR should be around 20% but Actual Value is 6%, same since I replaced the EGR, should I be stripping down Inlet and EGR Pipes and looking for a blockage, with EGR Motor and Valve out of the End of the Intake it didn't look Coked Up ?????????? that's why I changed the EGR Motor and Valve, to no avail ...................
It's got me foxed ATM
Going to leak test Pipework etc after lunch
I've googled etc etc.
"Offset Drift On Idle Code", the Van in Limp Mode, a German guy on U Tube rectified a leak on Boost Joint and cured it, hence me buying the Leak Tester Kit
Anyone got any Ideas ???????
Lunch getting cold, TTFN ...........
OK, back to it after Lunch ............
All Data with Exhaust back on still remains very similar, all the same stuff passes, the only anomalies are Air Flow and EGR rate, same as with Exhaust Off
*DPF Ash and Soot levels low and still well within spec, I suspect it is the recurrence of Fault codes causing lack of power not an Exhaust / DPF Blockage, because obviously I have to clear the codes before it will do a Re Gen, so then I drive it, and it pulls well until the codes come back
So we know Air Flow reading is high mg/Hub and EGR reading is low % but why
I have leak tested from Turbo to Throttle Butterfly, no perceptible Boost leakage, took it up to 20psi still good
I reckon I'm gonna have to pull all the Intake Manifold off it tomorrow to see if there is any leakage / cracks in plastic etc
What do you guys think ???
pic new Boost Leak Tester in action :-