diagnose my n80 purge valve

[A4TL]

first unplugged N80 to run 070 readiness test:
multimeter showed varying results:
0V 13V 10V..repeat
or constant 10V'ish (moving .005 increments down)
CEL: no communication to N80 (duh)
CEL: 16825 p0441-002 incorrect air flow

n80 plugged in:
vacuum on LEFT SIDE (to return line to gas tank) always when put finger there maybe 8-10hg if i had to guess (removing n80 and putting hand on right hose feels like 16-20hg).

no clicking, no ticking, no humming, constant 8-10hg of vacuum flow, put screwdriver head to ear (ghetto stethoscope) no clicking.

070 test goes to 100% then fails EVAP NOT OK:
CEL: 16825 p0441-002 incorrect air flow

Put straw in place of N80 valve (n80 still plugged in). car nearly stalling multiple misfire codes, CEL: 16825 p0441-002 incorrect air flow, no clicking from N80 or vibrations

what does your n80 purge valve do?

[old guy]

Vapors from the fuel tank are collected in the carbon canister. The N80 valve is used to regulate the flow of fuel vapors that are drawn into the intake manifold from the carbon canister. The N80 valve is operated by the ECU and is controlled by a duty cycle. The duty cycle will vary depending on engine temperature, oxygen sensor signal, load and speed. When the engine is off, a check valve stops the flow of vapors from entering the engine. This keeps the fuel vapors from entering the intake manifold and causing a rich mixture on restart.

If power to the N80 valve is interrupted or cut off completely when the engine is running, vacuum from the engine will open the check valve to allow tank ventilation.

[A4TL]

well mine doesn't click click evar, have you ever heard yours click? even with big screwdriver to my ear or holding it nada,zip even during 070 basic settings (EVAP test). is it an apparent sound or feel?

[old guy]

well mine doesn't click click evar, have you ever heard yours click? even with big screwdriver to my ear or holding it nada,zip even during 070 basic settings (EVAP test). is it an apparent sound or feel?

Wish I could help you but I have never actually attempted to hear it function. I am getting ready to go into the garage with my stethoscope and see if I can hear anything. I will let you know if I do.

[old guy]

OK.... I heard a very definite and continuous clicking. Sounds like yours isn't working.

[A4TL]

okay thanks! will go pick one up from dealer tomorrow. definitely no noise/movement

[old guy]

I should note that it did not click immediately. It took maybe 45 seconds or so before it began clicking. Once it started it clicked continuously. I listened for maybe 30 seconds before I shut it down.

[A4TL]

yeah mine was running from dead stop for 15 minutes nothing nada, twice today at a shop and at home with vag-com. it seems that the line going back to the gas tank pulls alot of vacuum and this valve regulates that because i took a straw and placed it inline and the engine choked down so bad it throw misfires on all cylinders and rpm was low. it seems the check valves are arranged to prevent boost/pressure from entering the system as they all seem to be arranged to flow vacuum only from the intake manifold. i guess it just bit the dust from age (95K of sunny mileage). if that doesn't work i've still got a month left on warranty but my deductible is sky high (aftermarket platinum transferred to me from PO). so i figure i'll give this a shot since the dealer would charge me an hour to install it lol.

[old guy]

Well good luck! Hope that corrects the problem. all indications are that it should.

[My OOOO My]

What are the signs / symptoms of a faulty N80 / Purge Valve ???

Where is it located?

[A4TL]

#1 fault - Vag code 16825 Incorrect flow evap
P0441 (obd-2 code)
Intermittent or lower limit exceeded

evap readiness = incomplete.

I'm gonna go get a new one today so maybe i'll make a side by side comparison if this fixes the problems.

[A4TL]

ordered new gas cap and N80 valve.
reference for 2002 N80 purge solenoid/valve is bosch 0 280 142 347
audi: 6q0 906 517 A

audi's part system doesn't show it as you would see it in your hand.

will update when it is in.

[A4TL]

these n80 valves have a flathead screwdriver adjustment in the end that doesn't have a connector. after beating on this thing on my desk i noticed that.

oddly when i applied power to the unit it now clicks when i adjust it left.

goes from low flow to high flow (blowing through it). hmmm....

[A4TL]

based on diagnosticators' information i have concluded my N80 is stick open. by adjusting it with a screwdriver i basically stuck it open more.

could very well be the reason i got the APR stage 1+ lean codes prior to this (2 months precursor warning).

if anyone wonders, blow thru the n80, if it leaks, and you can't adjust it and you are getting lean codes good bet this thing is throwing off the fuel system.

those check valves appear to fail too mine are crumbling, if they allow boost/vacuum to pass into the evap system could really screw with the air fuel ratio.

Will update with news when new n80 arrives

btw the check valve in front of the N80 was missing a piece of thermoplastic , i'm guessing maybe small enough to get sucked into the solenoid. I remembered this when i changed mine to USP kynar check valves. I was like why does the end (facing the N80) have a small bite out of the plastic. Didn't occur till recently that the piece HAD to make its way towards the n80 since vacuum is pulled back into the evap pump (in the back) to the gas tank. i guess it might be wise to replace that check valve before it crumbles and lodges junk into your n80 costing you $96 rather than $16 check valve

[A4TL]

for giggles i put the n80 valve on backwards (it flows the same regardless).

the CEL i didnt bother to clear. took it to the dealer for JU recall campaign. came back to washed car, dealer said i had a CEL "duh". drove back to work.

on the way home the car vibrated at a stop, wife said what was that? and the CEL disappeared.

Keep in mind the n80 is set fully counterclockwise (maximum flow) with screwdriver.

odd to say the least. maybe the junk clogging it got sucked out backflushed.

I got a new factory check valve to put in front of it. I was thinking a screen like those that dampen flow to boost gauges of some sort might not be a bad idea to keep the air clean going into the N80. it seems that everyone should at least replace the check valve before the N80 before it crumbles and gets sucked into the more expensive n80 valve :)

my check valves were toast crumbling all apart.

[kpatz]

I just replaced my N80 for the 2nd time this year, due to p0456 small leak code & CEL. My check valves look fine though. Seems like the N80 has a tendency to leak when pressure is applied on EVAP side along with vacuum from engine side. Vapor slips through, causing the leak test to fail, tripping the code and CEL.

Anyone else had their N80 fail in this fashion, especially more than once? I blew through the old valve while running the output test and there was no foreign material in it.

[A4TL]

why don't you put a filter on both sides of the N80 ? something that would let the air flow but catch particles?

adjusting the n80 valve is easy - flat head screwdriver. righty=closed more, lefty=open more.

crap usually gets stuck in the valve causing it to stay partially open all the time, at this point, or trying to close it to stop the airflow usually results in the solenoid not functioning (apply +12V DC to the terminal).

might be worth a shot to adjust yours, i had no luck though

[Elliott]

I hate to bump this old thread, but where exactly is the N80 valve? I am getting the emissions CEL related to a loose gas cap. Tightening the cap has worked most of the time but now it doesn't. I probably need a new valve.

[A4TL]

you sure you just don't need a new gas cap :)

the n80 is on top of your airbox. it has a wire plug going into it.

should be no air when voltage is not present and pass air when voltage is present. it clicks alot :)

[Elliott]

I'll probably get both, just to be on the safe side.

Thanks for the info!

[A4TL]

i'd replace those check valves too.they are what cause the failure.

piece of plastic fell off and lodged itself in the n80.

$96 (n80 at germanautoparts)
$16 (check valve) at dealer ouch! (there's like 6 of em)

when its warm out you fill up the car will feel flooded will take 5-6 tries to turn over.

i'd replace gas cap only first.

[BOPOH]

sorry to bring it up, i promise its for the better cause! N80 regulates(sucks) air INTO gas tank, or OUT of it?

[old guy]

sorry to bring it up, i promise its for the better cause! N80 regulates(sucks) air INTO gas tank, or OUT of it?

It purges the vapors out of the charcoal canister. It sucks the vapors from the canister into the intake track and ultimately burns them off in the engine.

[BOPOH]

ok, so my theory in other thread is right

[A4 Moda]

wow .. old thread. Good info though

[Quattro_USP]

I'm getting a EVAP CEL after the vacuum simplification. I disconected the lines and removed the vacuum resivior in the driver's side fender well. There was a line that ran to the back of the car does that have something to do with the EVAP? I thought all the EVAP components were on the passenger side of the car.

[Quattro_USP]

I believe the code said something about it wasn't able to purge, purge fault or something along those lines. Also my car seems to have a little hiccup upon start up.

[old guy]

I'm getting a EVAP CEL after the vacuum simplification. I disconected the lines and removed the vacuum resivior in the driver's side fender well. There was a line that ran to the back of the car does that have something to do with the EVAP? I thought all the EVAP components were on the passenger side of the car.

The line running down the drivers side operates the LDP (leak detection pump) and is very much part of the EVAP system.

[Quattro_USP]

Does this line need to be hooked up to a vacuum source? Is the vacuum resivior black and kind of conform to the firewall side of the driver's wheel well?

[old guy]

Does this line need to be hooked up to a vacuum source? Is the vacuum resivior black and kind of conform to the firewall side of the driver's wheel well?

If you want the EVAP system to work you will need a vacuum line with a check valve connected to the LDP. The vacuum canister looks like this:

[Quattro_USP]

Alright thanks thats what I took out, I'll have to hook that hard line back up to a vacuum source. Wish I didn't mess that hard line up now .

[BASARAB]

Bringing this from dead. Can I check the purge valve just blowing air thru it? Because I just removed it and tried to blow in it, but air wont go in any way.

[old guy]

Bringing this from dead. Can I check the purge valve just blowing air thru it? Because I just removed it and tried to blow in it, but air wont go in any way.

The N80 evap purge valve is normally closed, so no you should not be able to blow through it. The ECU opens the valve to purge the canister vapors.

[02A4_B6]

anyway to just take the n80 valve off, run the line to my catch can and place a resistor in the plug to disable it all together?

[alexza4]

anyway to just take the n80 valve off, run the line to my catch can and place a resistor in the plug to disable it all together?

you can remove all of your Evap crap, take the N80 off and plug the line going back to the gas tank. you will however still need to have N80 plugged in, tucked away somewhere otherwise you will get a MIL On.

[Sharkfin]

bumping this, what is the part number and does anyone have a DIY on how to replace it?

[ddanny86]

bumping this, what is the part number and does anyone have a DIY on how to replace it?

where is it located on a 2006 a4 2.0t...i cant find it.

[Outerfroggy1]

you can remove all of your Evap crap, take the N80 off and plug the line going back to the gas tank. you will however still need to have N80 plugged in, tucked away somewhere otherwise you will get a MIL On.

lots of questions!

Does the n80 valve only regulate the vapors from the charcoal canister?
Where does the vapor pressure from the gas tank vent?
If you remove/plug off the n80 valve will the charcoal canister become soaked with fuel? Any downsides to this?
Will it cause the gas tank to become over-pressurized?
Can the line to the LDP also be plugged without a CEL?

Im asking many questions becuase im going to yank all this stuff out in the future and I want to know what I can and can't do without a CEL.

[iamshayan]

also really interested in some information here,
i too am having problems with my evap. my car keeps throwing evap codes

[Sharkfin]

remove teh engine cover and it's on the right of the engine below and right of the PCV valve