2005 E320CDI "rolling coal" - Page 2 - PeachParts Mercedes-Benz Forum

ROLLGUY · #16 06-12-2017, 11:01 AM

Quote:

Originally Posted by brusk

I have the MBII scanner and personally hate it. I've email the company complaining that you can't data log. They seemed to be dumbfounded that somebody would want to do this. I bought an ELM327 v2.1 bluetooth dongle on ebay for under $10 shipped and downloaded Torque pro with charts for another $10 or so and can data log almost all the parameters that I was able to find in MBII. And not have to try to convert from mbar to PSI etc.

Then scanner has its places but mostly resetting and testing non driving situations. Maybe better on certain models but not my OM642 08 ML320 .

Very interesting. I did a search, and found that most if not all ELM327 devices don't work with Diesel (that's their claim anyway), and only a few work with IOS (I'm a MAC user). Still, it is a pretty cool device for just a few bucks.....Rich

brusk · #17 06-12-2017, 01:18 PM

Quote:

Originally Posted by ROLLGUY

Very interesting. I did a search, and found that most if not all ELM327 devices don't work with Diesel (that's their claim anyway), and only a few work with IOS (I'm a MAC user). Still, it is a pretty cool device for just a few bucks.....Rich

The ELM is just an ODBII reader so anything that is available could possibly be read. The problem is it's up to the application to actually read it. There are some things I can't read but if I could find the PID and formula I could.

Torque app works for Android but I think dashcommand is the ipad/iphone devices.

KarTek · #18 06-12-2017, 02:30 PM

Speaking in general terms, three things that cause smoke on diesels are inadequate boost pressure, inadequate air flow and poor fuel atomization at injection.

If the boost pressure is sensed after the intercooler, I would rule out poor boost/flow since it's reading what I would consider proper stock levels. If the boost sensor is before the IC, there may be a restriction that's choking the flow into the engine.

Finally, I would look at injection pressure and make sure it's up where it should be. Not sure of numbers here, I don't have a spec on it but I'm reasonably certain it's north of 21,000 psi. If it's low, there may be a malfunctioning IPR on the pump that's bleeding too much pressure off or the pump may be worn out.

ROLLGUY · #19 06-12-2017, 03:10 PM

Quote:

Originally Posted by KarTek

Speaking in general terms, three things that cause smoke on diesels are inadequate boost pressure, inadequate air flow and poor fuel atomization at injection.

If the boost pressure is sensed after the intercooler, I would rule out poor boost/flow since it's reading what I would consider proper stock levels. If the boost sensor is before the IC, there may be a restriction that's choking the flow into the engine.

Finally, I would look at injection pressure and make sure it's up where it should be. Not sure of numbers here, I don't have a spec on it but I'm reasonably certain it's north of 21,000 psi. If it's low, there may be a malfunctioning IPR on the pump that's bleeding too much pressure off or the pump may be worn out.

I am able to monitor the fuel rail pressure, and a few other items that might be important. I am not sure if the pressure at the injector can be measured though. One would think that if the engine has a rich condition, the computer would be able to monitor it and produce some sort of trouble code. I have to say that I put some fuel injector cleaner in the last tank, and the black smoke is not as thick as it was at first. I will try to get some numbers on my next drive. Thanks, Rich
Edit: I must not be thinking right, injecton pressure and rail pressure should be the same thing.

ROLLGUY · #20 06-14-2017, 12:01 PM

I made a few speed runs today, and monitored the rail pressure. At idle, it hovers around 350 bar, and gets to about 1,600 bar at the highest (still belching black smoke). I can rev it up just sitting with it in park, and it will hit as high as 1,000 bar. I am not sure if these numbers are in spec or not. Something to be noted though, I am having to touch the pedal slightly to get it to start. If I don't, it will run through it's cranking cycle and not start. Either warm or cold, it is the same.

ROLLGUY · #21 06-14-2017, 12:06 PM

Quote:

Originally Posted by KarTek

If the boost pressure is sensed after the intercooler, I would rule out poor boost/flow since it's reading what I would consider proper stock levels. If the boost sensor is before the IC, there may be a restriction that's choking the flow into the engine.

I believe the boost pressure is sensed in the manifold.

Diseasel300 · #22 06-14-2017, 12:34 PM

Quote:

Originally Posted by ROLLGUY

Something to be noted though, I am having to touch the pedal slightly to get it to start. If I don't, it will run through it's cranking cycle and not start. Either warm or cold, it is the same.

That seems like a BIG clue right there. Since common-rail diesels have no injection pump, everything is controlled by the computer, including the accelerator pedal "input". Injection is controlled by the computer, you shouldn't have to do anything at all with the accelerator pedal to start the car, and if you did, it shouldn't really have any bearing over whether or not it will start.

ROLLGUY · #23 06-14-2017, 03:55 PM

Quote:

Originally Posted by Diseasel300

That seems like a BIG clue right there. Since common-rail diesels have no injection pump, everything is controlled by the computer, including the accelerator pedal "input". Injection is controlled by the computer, you shouldn't have to do anything at all with the accelerator pedal to start the car, and if you did, it shouldn't really have any bearing over whether or not it will start.

The only thing I can think of is that the pressure relief valve (not sure of the exact name) is bleeding off when parked. I have a fuel pressure gauge, I wonder if there is a fitting that I can connect it to and see if the pressure drops after shutdown? Would my scanner show the fuel pressure after shutdown as well? (I suppose I could check that easy enough).

dieselbenz1 · #24 06-14-2017, 04:48 PM

I'm sure they bleed down in around 10 minutes as you are safe to work on the fuel rail after waiting 20 minutes after shut down.

ROLLGUY · #25 06-14-2017, 05:18 PM

I checked the pressure before starting, and it was at 6.50 bar. After starting, it went right up to 350 ish bar. After shutdown, it gradually went down to the 6.5 bar in about two minutes. Incidentally, I drove it on an errand, and it started up without touching the pedal. It was sitting for about a half hour, so maybe it is only when it is cold that I have to give it a little pedal to get it to start.

Murkybenz · #26 06-14-2017, 05:37 PM

You have boost and fuel , so egr must be remaining slightly open and diluting incoming charge with exhaust fumes which leads to a bad burn in the cylinder and hence the black smoke (unburnt fuel)

engatwork · #27 06-14-2017, 05:41 PM

You should not have to touch the gas pedal at all when starting - hot or cold.

ROLLGUY · #28 06-14-2017, 08:54 PM

Quote:

Originally Posted by Murkybenz

You have boost and fuel , so egr must be remaining slightly open and diluting incoming charge with exhaust fumes which leads to a bad burn in the cylinder and hence the black smoke (unburnt fuel)

That sounds logical.
Is it a big deal to remove and clean/replace the EGR on one of these?

ROLLGUY · #29 06-14-2017, 09:01 PM

Quote:

Originally Posted by engatwork

You should not have to touch the gas pedal at all when starting - hot or cold.

Yes I know, but Until I find out what is causing this issue, I have to do what it takes to get it started.
I did put some B100 in the tank the other day, but it has been working fine in my other vehicles. I even used some from the same batch in my previous CDI without issues. I would have a hard time believing that is the problem.

jay_bob · #30 06-15-2017, 06:20 AM

B (anything >5) is bad juju for CDIs according to MB. Apparently it's one of the constituents of bio that harms the injectors. There was a document published in 2007 that spoke about not using bio in a CDI but here is another explanation.

From my 2014 Bluetec owners manual:

"Bio-diesel - FAME (fatty acid methyl ester)
Mercedes-Benz USA approves the use of bio- diesel B5 for all BlueTEC diesel engines. The concentration of bio-diesel in the ULSD may not exceed 5% by volume.
Pure bio-diesel and diesel fuel with a higher percentage of bio-diesel, such as B20, can damage the engine and the fuel system. For this reason, they are not approved.
For more information, consult the gas station staff. The bio-diesel B5 label on the gasoline pump must clearly state that the standard for ULSD has been fulfilled. If the label is not clear, do not refuel the vehicle."

Side note - what about those states that have mandated B20 minimum, what are you supposed to do there?