Hi
I have now tried the local forums and the local Audi dealer without any luck, and I sincerely hopes that someone on this forum can be so kind to give me some hints on what is wrong with my car.
I have a Audi Allroad 2001 with the 2.5 tdi AKE engine. The problem started after I changed the camshafts because of wear. After this the engine lost some of the power at high end, and the torque at low rpm was also reduced. The most obvious proof I have found showing lack of power is that the Actual MAF reduces with increase of RPM as shown in graph below. MAP seems to be OK. I do not have any fault codes.
The picture show the pedal flat out in 1. 2. and 3. gear.
At the same time I changed the injector with the needle lift sensor. I suspected the timing of the camsafts was wrong, but after a short period of time the timing belt pulley on one of the camshafts collapsed resulting in bent valves and more. I upgraded to "new" cylinder heads that was taken from a BAU engine. This is the type using roller rocking arms. The heads and valves where cleaned for sot, and grinding paste was used in the end. At this time I was extra careful to get the timing correct. But the result was the same. Still lacking power.
What I have tried out so fare is:
x) Changed the MAF - engine got better but still lacking power.
x) Changed the catalytic convert since I thought the engine could not breath enough. I also cleaned the intakes for sot the first time, so I suspected loose sot could have entered the engine and clogged the convert. But no changes after replacement.
x) Changed the diesel filter - no difference.
x) Blocked of the EGR to eliminate the possibility of constant open EGR valve - no difference.
x) Checked the N75 valve - is ok.
x) Checked the VNT valve on the turbo - is ok.
x) Checked for leaks on the low pressure side of the intake tubes - no leaks.
x) Checked without the air filter - no difference.
x) Double checked the tensioner for the diesel pump belt - is as specified.
So I am close to give up here, but my thoughts have gone the diesel pump or injector. I did not use lot of time to bleed out the air and get the engine to start, but could a already "weak" pump get to much stress starting the engine up? For me it seems that the engine is not getting the diesel amount it require. The engine is a little bit rough cold, but I do not remember if it was the same before. After a couple of minutes it runs smooth. It is always very easy to start.
I have now tried the local forums and the local Audi dealer without any luck, and I sincerely hopes that someone on this forum can be so kind to give me some hints on what is wrong with my car.
I have a Audi Allroad 2001 with the 2.5 tdi AKE engine. The problem started after I changed the camshafts because of wear. After this the engine lost some of the power at high end, and the torque at low rpm was also reduced. The most obvious proof I have found showing lack of power is that the Actual MAF reduces with increase of RPM as shown in graph below. MAP seems to be OK. I do not have any fault codes.
The picture show the pedal flat out in 1. 2. and 3. gear.
At the same time I changed the injector with the needle lift sensor. I suspected the timing of the camsafts was wrong, but after a short period of time the timing belt pulley on one of the camshafts collapsed resulting in bent valves and more. I upgraded to "new" cylinder heads that was taken from a BAU engine. This is the type using roller rocking arms. The heads and valves where cleaned for sot, and grinding paste was used in the end. At this time I was extra careful to get the timing correct. But the result was the same. Still lacking power.
What I have tried out so fare is:
x) Changed the MAF - engine got better but still lacking power.
x) Changed the catalytic convert since I thought the engine could not breath enough. I also cleaned the intakes for sot the first time, so I suspected loose sot could have entered the engine and clogged the convert. But no changes after replacement.
x) Changed the diesel filter - no difference.
x) Blocked of the EGR to eliminate the possibility of constant open EGR valve - no difference.
x) Checked the N75 valve - is ok.
x) Checked the VNT valve on the turbo - is ok.
x) Checked for leaks on the low pressure side of the intake tubes - no leaks.
x) Checked without the air filter - no difference.
x) Double checked the tensioner for the diesel pump belt - is as specified.
So I am close to give up here, but my thoughts have gone the diesel pump or injector. I did not use lot of time to bleed out the air and get the engine to start, but could a already "weak" pump get to much stress starting the engine up? For me it seems that the engine is not getting the diesel amount it require. The engine is a little bit rough cold, but I do not remember if it was the same before. After a couple of minutes it runs smooth. It is always very easy to start.
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