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View Full Version : What is this broken mystery part/sensor?



snarf?
06-29-2011, 04:33 PM
[confused] Hey guys does anyone know what this is? I was just inspecting my new car and i noticed this under the plastic bit above the airbox:

A larger pic showing the area, sorry for blurry cell pic
http://img87.imageshack.us/img87/9310/mysterysensor1.jpg
By gators1270 (http://profile.imageshack.us/user/gators1270) at 2011-06-29

Closeup
http://img40.imageshack.us/img40/5817/mysterysensorclose.jpg
By gators1270 (http://profile.imageshack.us/user/gators1270) at 2011-06-29

Thanks

Audi_A4_
06-29-2011, 04:37 PM
Looks like a bad check valve. But I am on my cell so not for sure

Seerlah
06-29-2011, 04:39 PM
Yeah, bad check valve. Just replace it (don't use some cheap univeral Autozone crap).

walky_talky20
06-29-2011, 04:41 PM
http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Engine/Intake/Check_Valves/ES259630/

snarf?
06-29-2011, 04:45 PM
http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Engine/Intake/Check_Valves/ES259630/

I was just looking at ECS, thanks for the quick and accurate responses! I'll see if the dealership has it in stock tomorrow, if not ill order it.

Mind if I ask what it does? The ECS description is vague, can it alter engine/turbo performance if damaged?

revolution337
06-29-2011, 05:36 PM
I was just looking at ECS, thanks for the quick and accurate responses! I'll see if the dealership has it in stock tomorrow, if not ill order it.

Mind if I ask what it does? The ECS description is vague, can it alter engine/turbo performance if damaged?

well audi put it there for a reason so I can't imagine any good coming out of it being broken

Seerlah
06-29-2011, 05:38 PM
Check valves are used to make sure that air, water, or gas will only be able to move in one direction of the system it is placed on (ie air, water, or gas can only go in one way of the check valve, and out one way of the check valve). For this particular check valve, it is placed on the gas tank evap system, coming from the charcoal canister located under the spare wheel well on our vehicle. The gas tank builds up vented gas fumes, and it needs to be depressurised. On top of your air box (coming from your charcoal canister) is your n80 valve aka evap purge solenoid/valve. This valve (n80) releases the built up gas vapors in your tank, and recycles it into your intake system. One lines goes to your turbo inlet pipe and the other goes to the underside of the intake manifold, by the throttle body. The damaged check valve in your pic is the check valve leading from the n80 to the turbo inlet pipe.

snarf?
06-29-2011, 06:04 PM
Check valves are used to make sure that air, water, or gas will only be able to move in one direction of the system it is placed on (ie air, water, or gas can only go in one way of the check valve, and out one way of the check valve). For this particular check valve, it is placed on the gas tank evap system, coming from the charcoal canister located under the spare wheel well on our vehicle. The gas tank builds up vented gas fumes, and it needs to be depressurised. On top of your air box (coming from your charcoal canister) is your n80 valve aka evap purge solenoid/valve. This valve (n80) releases the built up gas vapors in your tank, and recycles it into your intake system. One lines goes to your turbo inlet pipe and the other goes to the underside of the intake manifold, by the throttle body. The damaged check valve in your pic is the check valve leading from the n80 to the turbo inlet pipe.

That answer was exactly what I was looking for, I really appreciate it. Using your information I did some more research and it's pretty clear to me, but for anyone else who searches this in the future here is a quote from PassatWorld that provides some more information on the purpose of the system:


The idea of the whole system is that evaporated hydrocarbons from sources like the fuel tank are stored in the evap cannister and then purged into the engine at appropriate times. That's what the N80 valve is for. When the ECU senses that conditions are right it opens the N80 and any stored hydrocarbons are sucked into and burned in the engine, rather than floating away into the atmosphere. You may already know all this; I aplogize if that's true. I find it easier to troubleshoot if I have some understanding of the system I'm investigating.


Thanks again. I'll be fixing the valve tomorrow.