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Only my second post here, sorry about that, buts its out of desperation. So here goes
Vehicle in question is a 1998 model W210 E280 Mercedes Benz running the M112 engine. Car was and still is extremely heavy on fuel, with grey smoke coming out the exhaust and a lip and mouth burning smell that isnt scared of the devil himself. Car diagnosed with a P0100 code using a iCarsoft MB V1.0 scanner connected to the 38 pin connector under the bonnet, as this model never came with the 16 pin obd plug under that dash. I have since purchased a brand new Bosch maf and fitted that, replaced plugs, plug wires and coil packs, changed all filters and oil. I have since noticed that fuel is mixing with the engine oil, which a cause for concern for me, as it could do some serious damage.
Im more than willing to check, test and do whatever I need to, I just need some guidance as to where to start this. I would greatly, and I mean greatly appreciate some sought of advice. I havent started learning live data yet, so Im hoping someone can spot something out of the ordinary with the car. Here are three frames of the vehicle taken with the above mentioned scanner
I actually spoke to a guy today, and he asked me if I knew what that air flow value was. I told him its a just over a 1000 odd kg per thingy. He said it might be the scan tool not doing a proper conversion on that.
Regardless, its a brand new Bosch maf, and im positive, if I put the old maf back it would probably be the same. I was wondering if it might have something to do with the O2 sensors. If I have fuel exiting the exhaust, I can just imagine what the O2 sensors look like.
Os there anything else I can look at that could cause such a deviation? Or anything else I can check pls?
If you look at fuel trim data with o2/ af sensor reading and post those we can see if they will need looked at. If sensor is stuck comanding more fuel then that could cause your condition as well. Do you have a scanner that can show live data?
Oil temperature is way too low, looks like an either open or shorted default value. If the PCM uses that as part of its open loop fueling strategy that could be making the the motor run rich.
Hardtopdr2 wrote: If you look at fuel trim data with o2/ af sensor reading and post those we can see if they will need looked at. If sensor is stuck comanding more fuel then that could cause your condition as well. Do you have a scanner that can show live data?
Yes, I should be able to do live data with the iCarsoft. ill do it tommorow, its late where I am, and cold
And yes, I noticed that the oil temp is super low. Couldnt figure that on, but when I spoke to another chap he said that would not effect fueling. One other thing, coolant temp in this printout, was lower than the temp reported by the gauge in the vehicle.
Assuming data is true, you have also an engine oil temp. sensor reporting -40 celcius (which increases pulse width but not that bad (Seems is unplugged)). I don´t know exactly how this sensor is affecting, but the fact you have injector firing at about 10ms is definitively a rich condition (They should be something about 5ms at that coolant temp.) This is also telling us PCM is responding to what she is seeing.
Is the air temp. reporting right? I mean, can you verifiy that temp?
I don´t have experience with this engine. I suposse it´s a 2.8 liter, which should be reporting about 3g/s at idle.
My first shot would be check power and ground at PCM and try to check whether or not scanner is telling me the truth. If so, then i would check for MAF sensor power and ground. Then unplug it and see how PCM reacts.
would assume that maf is reporting correctly, its brand new. As for air temp, I actually took 14readings, and all of them show the exact same intake air temp. No change on this or oil temp at all. Here are the remaining readings I took a few days ago.
Have you noticed coolant temperature sensor (ECT) is almost the same in all the captures?
Engine coolant and Maf readings are the main signals PCM takes into acount (at idle) to comand the amount of fuel. Anyway you have to many sensors reporting wrong readings. That makes me think if scanner is telling the truth (i doubt it).
If you have a DVM you can verify voltage at ECT sensor (cold engine, something about 3.5 - 4.5vdc (Neg test lead to negative battery lead). Hot engine something about 0.5 - 1.0vdc).
You can also check Maf voltage but here we need information about if signal control output is voltage or frequency.
Again, If scanner is right. Check for PCM (and sensors) power and ground.
Hate to say it but that data appears unreliable and unreliable data is the worst thing to have in diagnostics so get rid of that scan tool and save yourself the headache of chasing wrong data...
Only working scanner I have at the moment. I had a friend that came over with his MB Star a while back, and he couldnt get into any of the modules back then. Initially I thought that his unit was faulty, but then he came with a launch x431, same thing. Im surprixed thsi little scanner can get into the modules.
May I just ask, what is the pcm? I would like to go and check these items later today with my dvm
I'm leaning towards this vehicle doesn't have an oil temp sensor and the unreliable scanner has a pid for it so it fills it with a value(like the b2s2 full trims being 99.9%on many low level scanners) this data is not reliable enough to use , also the oil level sensor does not measure oil pressure so that light is unrelated to the oil pump
Had a bit of time now, and stuck a bi directional led across the injector leads while disconnected from the injectors with the ignition in position 2 and engine not running, and the led lights up. Not very bright, but it lights up. is that normal?
Checked resistance on injector plugs, on a few I get not resistance, and on other I get about 1k
