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Discussion Starter #1
Hello everyone ,
I'm trying to diagnose continuos low power on a 2003 Audi A4 TDI , engine code AVF . What I've checked so far :
- boost - ok , it's a bit over the required value (2400-2500mbar at full load ~2800rpm)
- MAF - ok , 1100mg/stroke
- pressure sensor - ok
- EGR -cleaned and checked for leaks
- stop valve - disabled
- intake manifold - removed and cleaned
- compression checked ~ 25 bar
- catalytic converter - removed
- tamdem pump - 9 bar @ 4000 rpm
- in tank pump - cleaned and checked
- fuel filter replaced
- injectors - smooth running control ok
- injectors - adjuster screws rechecked
- camshaft - there are signs of wear on the cams , especially on the exhaust ones

Could this whole low power output come from the wear on the camshaft ? The car feels exactly like it has no boost. No abnormal noise from the valve cover area. Please advise . Thank you.
 

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My pd 130 had the cam wear problem which caused the cam belt to fail, but it never lost any noticeable power. Did you check the air filter is clean?
 

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Discussion Starter #3
Hello and thanks for your reply. The air filter is new . The car boosts ok , it seems to be a fuel or mechanical related problem
 

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Maybe the fuel pump or the fuel suction in the tank is clogged? Do you have worn camshafts? Is your engine PD?
 

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Discussion Starter #5
Hello and thank you for answering . The engine is a PD 130bhp , AVF . There is a bit of wear on the tip of the cams , they are not prefectly round anymore ... especialy the exhaust cams on cyl. 1 and 4. I took out the fuel pump assembly in the tank and cleaned everything . There was a bit of dirt but not enough to block the fuel flow. Is there a pressure/flow test for the in tank pump ?
 

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I don't think your constant low power is from minor wear. Most of the time, by the time it's noticed all the cams are worn down. Why were the injector screws adjusted? Can you measure the accelerator pedal position and see if it's correct?
 

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Discussion Starter #7
Hello and thanks for your input on this .
I checked if the injectors were corectly adjusted because I noticed tool marks on the locking nut ... somebody removed the injectors at one time . I checked them all , and they were 180 deg backed off . I think this is the right setting for the AVF/AWX engines. The car was bought a couple of months ago and the owner did not know that it's low on power until I told him (it's my friend's first car).
The TPS is at 100% when I floor it .
If the injectors don't inject enough fuel shouldn't the smooth running values be very high (+5)? All the correction values are between -0.75 and + 0.75 .
 

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- this might sound like a stupid question, but is your AC working?
the reason I am asking this is that when FCM fails, in some cases it will send constant 12V to clutch coil and your clutch will be constantly engaged. If your blower fan is set to "off" you will not notice cold air from ac until you turn it to setting 1 and up. This will take away a lot of your torque. So just make sure the clutch is not spinning when it shouldn't. If cam lobes are worn that much, I guess you should also have some idle problems.
 
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