P0420 and P0171 need inspection asap HELP

[CRX772]

Audi A4 B7 153k

Just bought 2 weeks ago
Right before I bought prev owner replaced stock cat with catless dp, he said prior to install with stock cat no CELs present
Installed UroTuning 02 spacer on post cat 02
Was getting P0420 before I installed the spacer, now getting a P0171 with the spacer
Also, with and without the spacer car gets horrendous gas mileage (~200miles a tank) and stinks as if its running rich


Anyone know someone who would code out rear 02 for cheap?

Also considering a tune from 034 or Motoza as last resort, lmk what you guys think is my best option

Question: Do both 02's have an affect on fuel trims? I was under the impression that the front 02 was responsible for trims, while the rear 02 basically looks to see if CAT is working properly

Any advice for my situation would be greatly appreciated! thx!


UroTuning Spacer
IMG_5027_1024x1024.jpg

Here it is installed
IMG_3276.jpg

test2.jpg

[Jayz691]

Correct that the rear 02 is basically for cat monitoring. A p0171 is not caused by the spacer, sounds like you have another issue. Sometimes, if the spacer is too long, it'll cause a "post catalyst too lean" code, but that's a dif code. If it got rid of the p0420, then thats fine. I'd look elsewhere like vac leaks, exhaust leak pre upstream 02, etc, causing your lean code. Thats where id start. Vac lines, PCV, etc.

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[Theiceman]

Jesus it has to be P0171 month !!!

[CRX772]

Correct that the rear 02 is basically for cat monitoring. A p0171 is not caused by the spacer, sounds like you have another issue. Sometimes, if the spacer is too long, it'll cause a "post catalyst too lean" code, but that's a dif code. If it got rid of the p0420, then thats fine. I'd look elsewhere like vac leaks, exhaust leak pre upstream 02, etc, causing your lean code. Thats where id start. Vac lines, PCV, etc.

Sent from my LM-G710VM using Audizine Forum mobile app

Thx for the advice! Found the vaccum leak it was the hose that goes from the pcv to IM. Replaced with some extra rubber line I had lying around and some hose clamps and the code went away.

Got all the monitors fired up and headed to inspection station, as i was getting on hwy I got a oil pressure light on the dash. just my luck lol

Pulled over as soon as i could but motor has some nasty rod knock now. Why did I buy an audi

Oil pump prone to premature failure on the EA113?

Trying to figure out if it would be worth the money to rebuild/replace the motor.

[Cyrik]

Thx for the advice! Found the vaccum leak it was the hose that goes from the pcv to IM. Replaced with some extra rubber line I had lying around and some hose clamps and the code went away.

Got all the monitors fired up and headed to inspection station, as i was getting on hwy I got a oil pressure light on the dash. just my luck lol

Pulled over as soon as i could but motor has some nasty rod knock now. Why did I buy an audi

Oil pump prone to premature failure on the EA113?

Trying to figure out if it would be worth the money to rebuild/replace the motor.

Ouch. That's rough. The oil pump isn't exactly the most reliable one (it fails when the metal surrounding the balance shafts wears and causes oil to bleed through it, causing a permanent loss in pressure) but there could be a multitude of reasons of how you got to the point of low oil pressure. Unfortunately from what I remember 150k isn't exactly an "uncommon" failure mileage, I'm sorry. Iceman started an oil pressure thread detailing pretty much everything you need to know:

https://www.audizine.com/forum/showt...cussion-Thread

Your engine knocks when you're low on oil or your oil pump has failed to get the volume to everything in the block. You might get lucky and only need new bearings and a pump but with how much work it is to get to the pump (and the money on a brand new one) you might as well pick up a used long block, pricing will vary obviously (check car-part.com)

Why did I buy an audi

I ask myself the same question every. single. day. 5 year owner here...

[Theiceman]

yeah rod knock is super rare on these engines.. but sadly oil pump/ balance shaft failure isnt.. i think you might find you take the pan off and your oil pump/ balance shaft assembly is falling to pieces causing the noise.
not a lot of fun getting to that oil pump either as sub frame has to be moved to get pan off .