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2001 VW Pissat 1.8T Fix Emission Errors

4K views 6 replies 3 participants last post by  VetteEatingBeetle1.8 
#1 ·
Greetings All,

I own a VW 2001 Pissat 4 Cyl.1.8T. Not a mechanic. My local trusted auto repair shop stated they were hesitant to work on my car for lack of an on-site experienced VW mechanic. They also estimated they would end up charging me over $2000.00 to pass my emission test. I knew I needed to take matters into my own hands. I initially read 7 emission error codes. Cleared all codes replacing plugs/coil packs, MAF Sensor, MAF wire harness, several valves, upstream/downstream oxygen sensors, PVC sensors, crank case elbow hose, dozen misc. hoses, and 2 dozen clamps...most painful!!! Passed emission after little over $400 in parts ordered on-line.

After passing emission, and returning back home...engine light came on...again!! I need a experienced mechanic/owner to identify 2 remaining parts (connected to my intake canister identified as "A" and "B" in photo) that I did NOT replace (see attachment). These parts/hoses may/may not be related to my recent code(s) not yet identified.

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#2 ·
A looks like a check valve. That allows air to only flow in one direction noted by the the arrow stamped on it. You can remove and test it by blowing through it. If any amount of air goes through it in the wrong direction, replace it. There is probably close to a dozen of them throughout the engine that may need replacing. B looks like a purge valve solenoid. If it was bad you would get a code for it. You did not say how many miles or what codes you have.
 
#3 ·
(A)is just a check valve designed to allow air to flow through it in one direction but prevent any back flow. (B)is either N79,N80,Valve etc... you can do a full emissions/secondary Air injection(SAI) delete. There are kits online with all the hoses,clamps, block off plates and resistors needed to avoid any CEL’s . UROtuning.com and ECSTuning.com both have these kits for under $200USD. The best way to find and it avoid vacuum leaks is to eliminate any and all extra vacuum lines, SAI and Combi-valve. We’re problematic for me. I did a full emissions delete/SAI block off plate , and all were deleted from the ECU. I did it all for under $400USD. My 1.8t beetle now only needs 3 vacuum lines from the intake manifold to Fuel pressure regulator, to the Diverter Valve and to the Brake Booster. Also only have 1 boost line from the boost pipe to N75 then to Waste Gate. Also rerouted the upper PCV and lower crankcase breather hoses through a baffled catch can which is then recirculated back to the intake/inlet pipe. Im not sure why VW/Audi has over complicated the vacuum systems on their vehicles (more so on turbocharged engines than naturally aspirated engines) I’m guessing the over engineering (albeit a German calling card) is more or less to reduce or to mask the measurable emissions output. Also to make many of their systems dealership only services.



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#4 ·
Appreciate your response!!!!

Did not need to replace in order to pass my emission, but I was just
curious as to whether replacing either valve or both valves will improve
my fuel economy to any degree. Can you answer that question?

Thanks again,

Mark Z.
 
#5 ·
Appreciate your response!!!!

Did not need to replace in order to pass my emission, but I was just
curious as to whether replacing either valve or both valves will improve
my fuel economy to any degree. Can you answer that question?

Thanks again,

Mark Z.
 
#7 ·
Appreciate your response!!!!

Did not need to replace in order to pass my emission, but I was just
curious as to whether replacing either valve or both valves will improve
my fuel economy to any degree. Can you answer that question?

Thanks again,

Mark Z.
It may make a very slight difference, I would say not even a noticeable difference. If you had a noticeable decrease in mpg since recent service , ensure everything under the hood is plugged in as far as sensors and wires,grounds etc. if mpg is a concern in the VW mk4 world the TDI king of MPG.
 
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