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Im investigating my transmission. It is all about 2003 A8 D3 4,2 BFM with 09E tranny, done many kms already, and still going. 425k kms.
I have been looking topics in this forum many times, but no info that i would like to get.
Looks like that converter stall rpm is too low in my car. Its around 1340rpm.
ECM has only minor faults, about engine mount, O2 B1 Sensor 2 heater. I think engine performance is good. No missfires and so on.
Spark plugs replaced, coils should be OK, timing is OK, chains and vvt replaced. I dont see issues with engine now. Tranny fluids replaced. As tranny had done almost half million kms it still runs good enough i think.
But... I live in Lithuania and we have lot of snow here in winter.
See the photo:
Some time people need help in winter and as i have heavy awd car so i pull other cars and i noticed that if i have good new tyres and i have good grip engine does not spin wheels or pull.
I mean that at stall converter speed engine has not enough power to move the car. Or if i drive in high snow, more then 50cm deep and stop and try to move it is hard to move, You can push the pedal as much as you can, but still things happen like lack of power. But as i said before, car engine is still in good condition i think, it is still fast and pulls good on the highway.
Tranny is not slipping also, please see the photo below and give me some ideas. Or i just need high stall speed converter replacement? This is my first quattro, i was driving subaru for many years.
Say something smart not to buy subaru again
Photo below is full brake and full gas pedal. (stall test).
Check your transmission computer (TCU/TCM) for codes (errors). Also, is your instrument display lit up in reverse for the gears--bright background with dark gear letters?
A guess is your tranny may be in fail safe mode. If so, it would be stuck in like 4th gear. Hence the inadequate power feeling.
It could also be there is an issue with the torque converter lock up function--either at the converter OR at the control solenoid for it. That is inside the transmission case with the valve body. It is accessible a lot easier than pulling motor to deal with converter itself.
Any codes in the transmission computer will help meantime way more than arm chair guesses. You need VCDS or the VAG type equivalent. Forget any OBDII generic code scanner. Is the tool where you provided the screen shot capable of accessing the TCU/TCM? Any good independent repair workshop for VW's or Audis should have a better scan tool like that, if you don't have access already.
Thank you for your replay.
I forgot to say that TCM has no faults, and no emergency mode. I do have VCDS also, but readings are the same. The photo is the launch, its is oem with legal version. I repair cars for many years and as launch can read other cars too so i just keep it sometimes in my car if my friends need help. I can read with VCDS, but TCM memory is still empty anyway. I know how works mechanical part and even better about electrical part. But i think more about converter or its clutch issue. So this is what i would like to clarify. Tranny shifts good enough, its shift gears that i select and so on. But i dont know should stall rpm be so low or just my engine at that rpm is not rotating good enough. Because if engine at that speed torque is too low so it wont reach standard stall rpm also.
Tried to turn off the ESP? Does the engine rev up in those situation and the power is "gone" in the transmission? Or doesn't the engine rev up much at all when it doesn't want to move/pull?
I tryed ESP off. It is the same, engine doesnt rev up more than 1300-1400rpm if all 4 wheels have the same good grip. Power is not gone in the tranny. See the photo up. Parameter 001-2 is transmission input speed. It is 0 so if it would slip i would see some rpm there. The problem is that when i need to move from 0 with load ant good grip engine cant move the car. If car is moving and i select 1st gear in manual and moving around 2000rpm and press gas pedal it has enough power and starts spining wheels to the redline. It is something not good at the begining of engine speed 1000-2000rpm. Of the torque converter should slip more to let the engine rev little but more. I would like to find info about this car converter stall speed as a standard parameter.
I’m pretty sure there is an interlock on all VAG group cars where pressing the gas and brake pedals simultaneously restricts/cuts engine output. “Unintended acceleration” etc. So I’m not sure trying to force a stall test will give you accurate results.
Have you confirmed that the transmission fluid is the correct type, and that the level is correct? The 6HP transmission is very sensitive to both of these parameters.
If these are confirmed as good, then I’d be turning my attention to the engine. Something is causing it to operate with reduced power output.
Have you tried unplugging the MAF, seeing what that does? That’s a quick way of seeing if there’s an ECM/sensor issue possibly at play causing the reduced power output.
Hello,
Fluids are OK in this 6HP. But i dont see difference between gas+brake and if i hood it with a rope to another car. Engine is performing the same.
Intake manifold flaps could have this affect in engine performance? But flaps are OK also... I dont know. Need more ideas.
If it would be possible to find converter characteristics or another the same car with BFM engine and perform stall test. I think this is the best way to compare engine performance at low speed...
I think at this point you should also try searching for the ZF technical info in the 6HP. I don't recall stall speed as a spec published by Audi. Also if you believe the read out first posted, it says 268Nm. That's 198 ft lb's for those of us in USA. On my first quattro A6 with a 2V 2.8 V6 and 4 speed auto, I would have had a performance increase at that torque and pretty low RPM. It dealt w/ a good amount of snow fine. Read out also says supposedly 600nM nominal torque though? That is 442 ft lbs, so not believable--higher than even my 6.0 D3 W12 was rated as I recall.
Yes, check the intake flaps. If they are jammed to the long runners, you will have less low RPM torque. Known fail point on 4.2's as miles add up. Given how high yours are I would almost be surprised if it is not broken. I had to replace my 2000 C5 4.2 intake manifold by about 130K miles and a dozen years due to unrepairable broken flap issues.
Yes, with the Audi interlocks it will cut the throttle drastically after about 2 seconds on both pedals. Why it is hard to brake launch your typical Audi.
Yes, pull the MAF plug as suggested so fuel injection is running open loop--without being affected by sensors. Reference to O2 sensor BTW was something I didn't really buy into, since heating element mentioned is only found in the S1 (sensor one) position, not post cat sensor 2. By pulling MAF connector temporarily, the engine computer won't try to adjust fuel mixture from O2 sensor anyway.
I think at this point you should also try searching for the ZF technical info in the 6HP. I don't recall stall speed as a spec published by Audi. I never has a D3 4.2, but 1300+ rpm on a V8 doesn't sound out strange with <1000 idle speed. Also if you believe the read out first posted, it says 268Nm. That's 198 ft lb's for those of us in USA. On my first quattro A6 with a 2V V6 and 4 speed auto, I would have had a performance increase at that torque and pretty low RPM. It dealt w/ a good amount of snow fine.
Yes, check the intake flaps. If they are jammed to the long runners, you will have less low RPM torque. Known fail point on 4.2's as miles add up. Given how high yours are I would almost be surprised if it is not broken. I had to replace my 2000 C5 4.2 intake manifold by about 130K miles and a dozen years due to unrepairable broken flap issues.
Yes, with the Audi interlocks it will cut the throttle drastically after about 2 seconds on both pedals. Why it is hard to brake launch your typical Audi.
Yes, pull the MAF plug as suggested so fuel injection is running open loop--without being affected by sensors. Reference to O2 sensor BTW was something I didn't really buy into, since heating element mentioned is only found in the S1 (sensor one) position, not post cat sensor 2. By pulling MAF connector temporarily, the engine computer won't try to adjust fuel mixture from O2 sensor anyway.
Hi.
About torque, it is 268nm at 1350rpm. According to the oem lines it looks good i think. And about MAF at 2-3gear at redline i have a reading at about 255max. And flaps. Flaps vacuums are moving, but if they can broke inside so i cant see right now what is inside. If i remove throttle is it possible to see them physically with a cam or somethings?
Thank you for your replays guys.
02-06-2021, 05:10 AM
Converter stall speed
