machbuffet
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- Mar 10, 2012
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- Location
- Northern Ireland
- Your Mercedes
- E320cdi / 2006 / 3.0 V6
Hi Guys
2006 E320 cdi V6 Sport 90k FMBSH
I'm having an issue with my E320 cdi and wondered if anyone could help.
Some time ago I posted on this forum about the tapping noise that was coming from the engine. Following several visits to indies and MB dealer, I was told that it was quite normal and they all do it to some extent. However, recently I happened to visit another indie and they said straight away that it was an injector seal. He replaced all six, reground, new bolts etc and the car sounds totally different - soooooooo quiet and no tapping.
However, it's left me with another headache. Since picking up, from start to warm up, at around 1000 to 1600 rpm there is a misfire. This happens whilst stationary and when driving. If you try to hold revs within that range it misfires. As the car warms up, the range narrows to the point that at about 70 deg coolant temp (gauge reading) it does it at 1000 rpm and eventually disappears altogether when revving in neutral, but still slightly noticeable under load while driving (noticeable in slow moving traffic).
Doesn't affect the acceleration, it pulls like a train and once warmed up, is hardly noticable.
I suspected a fuelling issue, as the exhaust fumes are particularly pungent during this period. As a precaution, I went around all of the injectors and noted the numbers on the tops. I compared this to the smooth running printout he gave me and found that no1 and 2 were swapped. I went back and he re programmed them (took three attempts mind) and seems to be correctly numbered now but its still doing the same thing.
At all times, cold and hot, the idle quality is excellent. This only happens when you bring it off idle.
Recently I have also replaced the back pressure sensor, and had a compression check done (all excellent)
I'm not an expert, but thanks to these forums I can at least try to figure out some ideas. Would it be a temp sensor issue? I've heard they don't always throw fault codes.
What about crank sensor? Do they signal the load + engine speed to ECU to meter fuel?
Also, re the numbers on the injectors and programming them into the ECU. How does the ECU know the correction values for each injector ever made from this number. Does it require some sort of live internet connection during input to download the specific value for the injector. It's just a jumble of letters and numbers, often having no numerical content and I just wondered how the ECU can determine values from this. I was told that each injector has it's own value and must be correctly programmed but wondered how the values are obtained by the ECU.
The other thing is, I'm just assuming that the cylinders are numbered (looking from the front) Drivers side - 1, 2, 3 front to back and passenger side - 4, 5, 6 front to back. Is this correct?
I've booked back in to see them next week but in the meantime, I was wondering if anyone could help. I love the car but it's driving me mad and causing a bit of concern.
Thanks in advance
Barry
2006 E320 cdi V6 Sport 90k FMBSH
I'm having an issue with my E320 cdi and wondered if anyone could help.
Some time ago I posted on this forum about the tapping noise that was coming from the engine. Following several visits to indies and MB dealer, I was told that it was quite normal and they all do it to some extent. However, recently I happened to visit another indie and they said straight away that it was an injector seal. He replaced all six, reground, new bolts etc and the car sounds totally different - soooooooo quiet and no tapping.
However, it's left me with another headache. Since picking up, from start to warm up, at around 1000 to 1600 rpm there is a misfire. This happens whilst stationary and when driving. If you try to hold revs within that range it misfires. As the car warms up, the range narrows to the point that at about 70 deg coolant temp (gauge reading) it does it at 1000 rpm and eventually disappears altogether when revving in neutral, but still slightly noticeable under load while driving (noticeable in slow moving traffic).
Doesn't affect the acceleration, it pulls like a train and once warmed up, is hardly noticable.
I suspected a fuelling issue, as the exhaust fumes are particularly pungent during this period. As a precaution, I went around all of the injectors and noted the numbers on the tops. I compared this to the smooth running printout he gave me and found that no1 and 2 were swapped. I went back and he re programmed them (took three attempts mind) and seems to be correctly numbered now but its still doing the same thing.
At all times, cold and hot, the idle quality is excellent. This only happens when you bring it off idle.
Recently I have also replaced the back pressure sensor, and had a compression check done (all excellent)
I'm not an expert, but thanks to these forums I can at least try to figure out some ideas. Would it be a temp sensor issue? I've heard they don't always throw fault codes.
What about crank sensor? Do they signal the load + engine speed to ECU to meter fuel?
Also, re the numbers on the injectors and programming them into the ECU. How does the ECU know the correction values for each injector ever made from this number. Does it require some sort of live internet connection during input to download the specific value for the injector. It's just a jumble of letters and numbers, often having no numerical content and I just wondered how the ECU can determine values from this. I was told that each injector has it's own value and must be correctly programmed but wondered how the values are obtained by the ECU.
The other thing is, I'm just assuming that the cylinders are numbered (looking from the front) Drivers side - 1, 2, 3 front to back and passenger side - 4, 5, 6 front to back. Is this correct?
I've booked back in to see them next week but in the meantime, I was wondering if anyone could help. I love the car but it's driving me mad and causing a bit of concern.
Thanks in advance
Barry