I'm having trouble with my motor!!! I keep on getting code P0171 - System too Lean (bank 1) and sometimes I get code P0170 - Fuel Trim. Could this be caused by the defective part below? What is this part called? I've checked all hoses and the MAF was replaced not too long ago.

 

here is the one i got to replace mine

http://www.034motorsport.com/product...ducts_id=18010

i belive that it is called the "F" hose

 

Yup, replace it.

Breather hose, T hose, F hose, whatever you want to call it, that's your issue (or one of them). Those breather hoses collect oil and collapse and create vacuum leaks. Follow it all the way down and you'll find a metal section that goes into another plastic section, which goes into the block. Check all of those for cracks. Follow the breather hose the other way towards the airbox. You'll find a series of connections made of rubber or plastic. They are all prone to collapsing or cracking.

If your 1.8T has 80K miles or more, these breather hoses can all become suspect. If any of them collapses or cracks, you'll end up with lean fuel trim codes.

 

cool. Thanks guys! I'm waiting for the part to come in. I hope this works.

 

so replacing the breather hose didn't do a damn thing different. I still get the same code. I bought the new one from 034motorsport.com and it's nice and it fit but I still get the system too lean code (p0171 bank 1). I'm really starting to hate all problems with the B5's! So any other suggestions on how to fix this code problem would be great.

 

Did you clear the codes and reset the MIL? Additionally, did you follow the breather hose to the block and the airbox? There are unfortunately many connections along that breather hose that can cause lean codes.

 

yup checked all connections. I cleared the MIL and it will stay off for a while, but after driving around for a bit, it comes back on. I can drive like 20-30 miles before the CEL comes back on. Its wierd, the makes power and performs great and shows no signs that there is a problem, but the light still comes on!

 

Do you keep getting the same code P0171?

(This is kinda dangerous, do it at your own risk) You can use propane or brake clean to help find your vacuum leak. Put it near a suspected leak, you'll hear a change in RPM when you find it.

Additonally, make sure the MAF is plugged in securely and that the hose connections around the airbox are tight.

 

16555/P0171/000369
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Contents [hide]
1 16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean
1.1 Possible Causes
1.2 Possible Solutions


16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean
Possible Causes
Mass Air Flow Sensor (G70) defective

Possible Solutions
Check Mass Air Flow Sensor (G70)

Check Fuel Pressure Regulation

Check Fuel Pump

Check Injectors

Check Intake System for Leaks

Check Exhaust System for Leaks

Check Secondary Air System for Leaks

Check Vacuum Pipes for Leaks

 

Any luck? I am having the same damn problem!!! So far $400 in parts countless hours of time and can't clear this damn code. I can't do emissions without it clear, and I am out of time. Running on expired tags!