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audi a4 awx less powerful

15235 Views 23 Replies 4 Participants Last post by  stig
hello i am new to the forum and i have problem with my audi a4 b6 1.9 tdi awx it have 30% less power than it should have. I checked turbo and the variable geometry no problem, with maf disconnected its less powerful. On diagnostic its not showing errors, no smoke from the exaust engine starts almost wihout cranking no weird sounds from the engine, what can be the problem ....sorry for my english im from macedonia
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Thanks for your opinions @: chittychittybangbang the car it's 2002 year i've tried with new air filter and no improvements i will try with new fuel filter, i want to try with maf from another car with the same egine code but i dont know code for the radio bechause i shoud disconnect the battery for 30 min when changing the maf to reset the ecu. The car it's not going in limp mode it's constant loss of power on the diagnostic no errors showing.
You do not need to unplug the battery to reset the ECU.

You can only get the radio code by removing the radio and finding the serial number. Then you can go to the dealer for the code.
What should i do to reset the ecu without unplugging the battery, or just replace the maf sensor and the ecu will reset itself?
I dont have vag com or vcds and that's making things more difficult.
ok guys i've changed maf sensor with another car and no changes the car it's still the same also i've changed n75 valve and no improvement these car it's making me crazy no problems on diagnostic engine runs perfect but no power it's like 100hp instead of 130
Clogged catalytic converter? You can test this by disconnecting the exhaust.
Today removed the turbo and the catalytic converter, the turbo it's in perfectly working order variable geometry it's moving freely , catalytic converter was empty there was nothing in there probably previous owner was thinking catalytic converter it's clogged and he removed the ceramic core. Tommorow i will try with map sensor from my friends 98 1.9 tdi afn passat i think the sensors are the same, if there is no improvement i will buy new original maf sensor
That's the variable geometry from my turbo
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Before few hours i've tried with another maf and map sensor from passat with the same engine code and car is the same slow acceleration, tomorrow i will change the fuel filter if its the same the car will go on sale....
Guys i think i found the problem, camshaft its damaged see the pictures

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Yep, totally beat up. It should cause some idle problems but I'm not sure it would cause such a huge power loss. I would have removed the valve cover to inspect it before removing the turbo but at least you have rule that out.

Also post moved to general since it's way beyond a quick intro.
No idle problems it's about 20 to 30% loss of power compared to another tdi pd awx engine sound of mine its much louder from inside valve cover. When i rev the engine reving it's very slow, i think bechause the valves are not opening completly engine can not breathe easily. What do you think should i change the lifters too? I will see for damage on them if they are not damaged i'm thinking to leave the old ones.
EGR valve was one of the first things i've checked nothing wrong with it, and it's cleaned from the previous owner, i think the problem is worn camshaft. All camshaft lobes are almost 1mm worn do you think that will afect performance?....
Guys i'm back, still no power from my audi i have now vcds diagnostic and actual maf readings are higher than specified. Specified maf value is 250 and actual value is 400 on idle, i tried with another maf the readings are the same, i hooked up vcds on another car with the same engine code like mine maf readings were the same actual 250 and specified 250. Egr valve its stuck closed the membrane inside it's damaged. Can the egr valve be the cause of the incorrect values ​​of the maf sensor, and also cause of loss of power?

thanks for understanding and sorry for my bad english
hi i'm back again, on my audi i've changed camshaft lifters and followers it's all new but this is a big dissapointment to me the car is the same again no change in the performance old cam was damaged on two ehaust lobes on cylinder 2 and 3 they were worn 2mm and the lifers were damaged, what can be the cause on this problem this car it's making me crazy lot of work and money but no change in performance please give me some opinion im stuck without any ideas.......................... :confused:
I certainly sympathize with you here, but am out of ideas. Exhaust or intake clogging? Start from the beginning and double check?
on vcds in channel 13 (idle speed smooth runing control) i noticed higher value at cyl #4 than other three cylinders the value is sometimes around 1.84 at coolant temperature 85 degrees and if coolant is around 70 degrees the alue on cyl #4 is around 2.33 i wonder what this means ?? other three cylinders are around zero.
Chitty im waithing for your oppinion what do you think could my problem with loss of power be related with faulty injector? ........the car has no power below 2000rpm
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