A mate of mine bought a bit of a lemon of an a3 recently. It a 2006 8p Quattro running a AXX 2.0 tfsi. I have been rectifying problems with the cruise control multi function steering wheel and various bits of missing trim.
However about a month ago he mentioned the car had gone into limp mode when pushed on a motorway run. I plugged it in to VCDS and it gave an under boost code 00665.
I removed the diverted and the diaphragm was split. It was replaced With the latest revision. He also mentioned the car had misfired and a fault for a mis on cylinder 1 was found. Suspecting a coil pack a new Bosch one was put on as they are cheap a 30 quid.
Anyway about 3 weeks later he called. It was missing again but really bad. I had a shufty and it had logged mis fires on cylinders 1 and 3...? The 00665 code was also back again at 89 percent load.
Long stor short new genuine NGk plugs went I and it was better but lumpy on idle.
I watched on measuring blocks and it was picking up mis on 1 and 3 at idle and at very light throttle under 2000 rpm.
Since then it has played up twice in about 10 days. When you pull the plug it is wet with fuel.
I did a comp check and it did 180 psi across all 4 no bother. I checked the cam follower and lobe for the high pressure fuel pump and there was no wear.
I pressure tested the system and found no leaks.
I have however now got a PCV valve as they are known to Cause the 00665 code and mis fires at idle. The part has been revised many times according to parts guy.
I also found that the turbo intake pipe has a clip snapped off from the air box/top cover.
It also has a deep gouge which is close to perforated so I have one of those too.
However I am concerned that neither of these parts will cure the mis fire whic is recurring after a couple of days.
I am aware that as it is a direct injection engine the intake valves are very prone to cokeing up. It is possible to strip off the intake manifold and with the valves closed scrape out the crud. A long and laborious job.
To my simple mind I would have expected it to show on the comp test.
The other thing that I have considered is a failing injector on 1.
However they are expensive and I don't like guessing. I tried to find the injectors on the measuring blocks but could only find the overall rail pressure.
Also I have been reliably informed that once a mis fire is detected the ecu will shut that injector off and give the wrong impression when looking on VCDS.
The other thing I have thought about is that the car is mapped and it is expecting to see higher boost and fuelling but on standard engine can't deliver. The car has definately bee played with as the stereo was all changed speakers etc. it's running forge boost hoses and I think the air box was removed and running some sort of cold air intake etc.
Ideas o a post card please. Once I have replaced the PCV and intake pipe next week I'm out of ideas, other than injector.
I'm trying to put off the cack job of intake mani off etc
sorry for the big write up but wanted to give all detail. Ste.
However about a month ago he mentioned the car had gone into limp mode when pushed on a motorway run. I plugged it in to VCDS and it gave an under boost code 00665.
I removed the diverted and the diaphragm was split. It was replaced With the latest revision. He also mentioned the car had misfired and a fault for a mis on cylinder 1 was found. Suspecting a coil pack a new Bosch one was put on as they are cheap a 30 quid.
Anyway about 3 weeks later he called. It was missing again but really bad. I had a shufty and it had logged mis fires on cylinders 1 and 3...? The 00665 code was also back again at 89 percent load.
Long stor short new genuine NGk plugs went I and it was better but lumpy on idle.
I watched on measuring blocks and it was picking up mis on 1 and 3 at idle and at very light throttle under 2000 rpm.
Since then it has played up twice in about 10 days. When you pull the plug it is wet with fuel.
I did a comp check and it did 180 psi across all 4 no bother. I checked the cam follower and lobe for the high pressure fuel pump and there was no wear.
I pressure tested the system and found no leaks.
I have however now got a PCV valve as they are known to Cause the 00665 code and mis fires at idle. The part has been revised many times according to parts guy.
I also found that the turbo intake pipe has a clip snapped off from the air box/top cover.
It also has a deep gouge which is close to perforated so I have one of those too.
However I am concerned that neither of these parts will cure the mis fire whic is recurring after a couple of days.
I am aware that as it is a direct injection engine the intake valves are very prone to cokeing up. It is possible to strip off the intake manifold and with the valves closed scrape out the crud. A long and laborious job.
To my simple mind I would have expected it to show on the comp test.
The other thing that I have considered is a failing injector on 1.
However they are expensive and I don't like guessing. I tried to find the injectors on the measuring blocks but could only find the overall rail pressure.
Also I have been reliably informed that once a mis fire is detected the ecu will shut that injector off and give the wrong impression when looking on VCDS.
The other thing I have thought about is that the car is mapped and it is expecting to see higher boost and fuelling but on standard engine can't deliver. The car has definately bee played with as the stereo was all changed speakers etc. it's running forge boost hoses and I think the air box was removed and running some sort of cold air intake etc.
Ideas o a post card please. Once I have replaced the PCV and intake pipe next week I'm out of ideas, other than injector.
I'm trying to put off the cack job of intake mani off etc
sorry for the big write up but wanted to give all detail. Ste.
. could not move the miss from cyl 2.. no way no how.. ohmed injectors ..all fine, sent them for a clean and all was good, as they were all bad, no 2 was worst.
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