How O2 sensors react to exhaust leaks: '01 Audi A4

[@EXOVCDS]

You probably already know, so this is more for your viewers... be sure to check the engine mounts (common reason for flex pipe failure). Good video!

[@PineHollowAutoDiagnostics]

***** Great tip! I had the mounts off not too long ago for the clutch job; they looked to be in good shape :) Those non-original flex pipes were missing the outer braiding for the last three years...very surprised they held up as long as they did lol

[@amazoidal]

In Cali, we have very extensive smog tests but no physical inspection so no problem with bent wheels (which can be fixed).Smog inspectors use mirrors to find "spacers".

[@SuperlativeCatalyst]

I'm glad that you enjoyed your extended intro

[@bernardaflores1720]

I do agree, money pits can be a great learning experience as long as you got the money to keep fixing it. Spacers do not seem to work as well with cars that have AFR's in the front!

[@techsavantlove]

subscribed!Love your style. Have added you to my top 5, including danner, south main, and schrodinger

[@PineHollowAutoDiagnostics]

+douglas lee Thanks Douglas! Honored to be in the "club" :)

[@GlycerinZ]

Danner and Shrodinger are great for advanced DIY, I also like Ericthecarguy and Ratches and Wrenches. I've learned from all of em.

[@jdean399]

Nice video, thanks, always learn something from you. I found your channel after your visit to South Main, they also are good videos.

[@amazoidal]

Good thing it's a V-6. The 2.0 TSi 4 cylinder has had 3 revised timing chain tensioners. Many grenaded engines over the years.

[@bthompson1767]

By installing those o2 sensor spacers how does this effect your lean or rich conditions

[@SteveRobReviews]

Interesting- I use the anti- fowlers as well. Works great on domestics I find better than imports. Seems most people change the rear O2 when they get a 420 (HA) and the spacers don't work well. I find an old working O2 with the spacer is better. 👍

[@PineHollowAutoDiagnostics]

Steve Rob Hah that used to be my first fix as well...replace the O2s and see if the code returns. However I don't like the non-guaranteed try-new-parts approach anymore. The defoulers are cheap so there's nothing to lose!

[@dubistverrueckt]

Nice video! Now I understand a lot better that it's my cats (meow!) that are failing and not the 02S! The #2s follow their #1s almost identically. However... when you put the sensors back in you showed the rear ones screwed in _before_ the rear catalysts instead of after them and even mentioned that those are not monitored. It just so happens that in trying to solve my California smog nightmare, I was looking at the CARB regulations for after-market catalytic converters that applied to Audis and VWs, and for 2001 A4 quattro 2.8 cars it requires that all 4 converters be monitored; therefore, the post-cat sensors should be _after_ the rear cats so that these, too, can be monitored. Could it be that your friend's rear cats were installed backwards with the O2S bungs towards the front instead of the rear? This all-cat monitoring scheme only shows up in the 2000 and 2001 A4 2.8 quattros -- all others only monitor the front cats. Or am I crazy? Here's the link to the CARB list: arb.ca.gov/msprog/aftermkt/devices/eo/D-193-96.pdf

[@PineHollowAutoDiagnostics]

+dubistverrueckt Wow that's some crazy info! I've been thrown off several times by "California vs. Federal" emissions vehicles. And this Audi A4 here has been "restored" from salvage, so the Emissions label is definitely absent from the hood haha!

[@zochpeter]

Ivan, I do not know how it shows on generic OBD2 but VW/Audi uses 2 long term strategies. 1 for idle and 1 for at load. that might be the reason why you see 2 short term fields on dbd2

[@jamesmatheson4746]

proper mechanic keeps all the emissions systems working with no check engine light

[@pigeonsil240sx]

on a turbocharged car does engine run lean idle and rich under boost? i have a old nissan 240sx turbo and thought it was a boost leak,found a few and fixed them but still lean idle/rich under full boost,i then pressurised the exhaust and found a leak pre o2 where turbo meets manifold,i understand why it would run lean at idle because exhaust pulses draw in fresh air but i dont understand how it cause rich under boost since the exhaust becomes pressurized any theories or does this sound like two seperate problems where the exhaust leak is causing lean idle but rich wot in boost may be caused by somthing else? the car has a wideband o2 with guage to moniter afr.at idle i see up to 17:1 afr and 10:0 afr full boost. also i did get a knock sensor code,i suspect this was caused from the lean idle,do you think this code would cause the rich condition at full boost??

[@douglas2lee929]

In many states having tires sticking out beyond the fenders is a violation. Those front tires look like they are sticking out like two inches.

[@jandjmca]

the old flex pipe has an inner flexable tube, that the replacement, does not have, will this give a fault on 02 SENSORS AS I HAVE REPLACED BOTH WITH OTC FLEX PIPES and getting 02 faults

[@RoadHeros610]

That's a big you were working ok in an s4 it was and still is a rare car

[@amazoidal]

Nothing is more expensive than a bargain used German used car. Endless money pit.

[@bryantoth5249]

Hello, Little help. I’m trying to figure out how a pressurized exhaust system can bring air into the O2 sensor?

[@gooe9561]

Secondary air injection.

[@tidalnebula9329]

I have a sonic with a cat manifold then a flex pipe then a secondary cat my flex pipe is leaking it's kinda loud but ehh but it also threw a code p0420. Catalyst system efficiency below threshold bank 1. My question is simply could my exaust leak cause this code?

[@mschentag1]

Yes. Exhaust leaks are the usual culprits for P0420 and P0430 codes. The next likely culprit is the upstream and downstream sensors. If those two fail, its likely the cat, you can prove it with a propane test before you spend $$$$$ on cats

[@gooe9561]

A simple oxygen storage test should be used. Also, I have to disagree. The most common cause of a P0420 is a failed catalytic converter.

[@JVerschueren]

Well, if one has aftermarket rims, one can't drive it/treat it like it's a throwaway banger. Apart from the rims themselves, the state of his rotors and calipers is shocking, to say the least. I thought I treated my (totally stock, BTW) car poorly, but, after nearly 20 years, mine aren't nearly as bad. That said, I also do question the design of the rims: ok, looks are important, but would it have hurt to leave access for a standard wheelnut socket? -I highly doubt it.

[@PineHollowAutoDiagnostics]

I made him get stock Aluminum rims with regular wheel bolts after fighting to get those aftermarket garbage rims off haha! Oh and I had to get them off to replace the extremely rusty rotors!

[@isrealperez9069]

So you are saying that if I have exhaust Leak it will mess with my fuel trim and causes p0420

[@mrkzj2]

How far from Penn State? I visit pretty often.

[@stuzman52]

Hey Ivan, your friend looks like he's pretty rough on that Audi. Bent rims, mmm. And the O2 rear sensor did look a little better with the spacer. Hopefully, it won't bring the engine light back on. Oh, one question Ivan. Tell us how you really feel about German cars (smiling)....Take care my friend!

[@PineHollowAutoDiagnostics]

stuzman52 Fun to drive...not fun to fix haha :) They do have the best corrosion protection in the business though (along with the Swedes), so in the Northeast I would consider owning a Euro car just for this reason alone!

[@ronaldoquintos1675]

You are a bright kid

[@vincebauer4777]

Ivan u should get a quick jack I just got mine it's great wow huge difference 1400 not that badly priced Google it

[@precisiont5188]

Are you in Oregon?

[@Jpilgrim30]

I freakin HATE drilling out studs like that. Talk about a tiring job especially when you have to do more than one. Those hardened studs dull out bits fast.

[@EdWeibe]

shit on it. why not just do the two that are still good then tack weld the last?

[@Gewgoal]

Hi Ivan! For lean conditions p0171 and p0174 is there a way to look at fuel trims to differentiate from a Vacuum Leak, Exhaust Leak or Bad Fuel pump? My LTFTs are around 20-30 at idle and cruise and have hit 40%.Under hard acceleration LTFT drops down to around 4%. I have all new PCV valve, pcv hose, A/F, 02, MAF sensors and a new fuel pump Resistor/Relay. Banks 1 and 2 LTFT differ slightly, bank 2 is usually a bit higher thank bank 1. SUBSCRIBED!!! THANKS! STFT does seem to change much when i rev to 1500-2000 rpm. I read that it should drop if its a vac leak.

[@PineHollowAutoDiagnostics]

Sounds like vacuum leak. Keep in mind it can also be an "internal" vacuum leak like a stuck open purge valve, brake booster, or EGR. Smoke test the intake and pinch some hoses :)

[@Gewgoal]

motoYam82 thanks for the tip and reply! 👍👍

[@eastpantherbenz]

As an owner of a 03 BMW 325i, there is nothing more expensive than a cheap german car Lol. At least with the E46's if they haven't been abused you can take caer of the cooling system and the oil filter housing gasket as well as some other weak points all at the same time. Then your usually good for awhile.

[@PineHollowAutoDiagnostics]

bimmerman3 Yup couldn't agree more. One of he first things I had to do to this car was to replace the thermostat....which lives BEHIND the timing belt!!! That's like a 6-hour job for a 10-dollar part! Germans are generally logical in engineering design, but that was a big FAIL lol

[@eastpantherbenz]

I can't complain about E36 or E46 BMW's, once the fan and shroud are off everything is pretty easy. The newer E90's cars are a little different with the electric water pumps and thermostat towards the bottom, but you don't have to take the front of the car off to fix it. Wish we all had a lift like eric has.

[@AllenNix-iz6ev]

Needs to install curve finders .... Lol

[@halleffect1]

my neighbor would say that engine bay is so packed you could pour water on the motor and it wouldn't hit the ground.

[@deepsquat600]

how the heck did I miss this one ?

[@dacoda6668]

Here in Europe i dont dare buying these Euro trashes since they’re endless money pits! we only lease them for 2-3 years new! i got Japanese cars! they take a beating quite well

[@vitaly_vasilev_2012]

Спасибо.

[@timowallin8020]

You Know Data from scanner on Euro cars can only give you a directional! You Cant look even slow sensor a like o2 sensor and compare them to another one. You need a scope for that. put hay for this(see thing help) its ok. just if you know the bank 1 could allso be the worse one, as the slow take from the real thing by scanner, just hapend to get datapoint from "better place"

[@EdWeibe]

now where is the exhaust leak? On my Ford, I have three cats. I have an exhausst leak before the last cat. nevermind. I think I see the rest of the footage....

[@robertopenheimer1451]

I would think that O2 spacer is illegal. I would not stick my neck out for a "friend" just to get them past inspection. When someone defeats an emission control on their own car it's not as severe as a paid mechanic or someone with a licence doing it. the fines are pretty severe.

[@letitgrowdad5268]

I find the new Snap-on scanners gift tax way too many pids and information,

[@scottmcintosh2988]

They race these up Mt. Washington in New Hampshire 6,300 FEET Tallest on the east coast . Came in 1st , 2nd , 3rd they would floor it stab the breaks on the corners . Endless money pits !

[@robertbrandywine]

Aren't you breaking the law (on camera no less!) by putting that spacer in there? I would think you could have your license revoked.

[@startover125]

I need my car, even though it's 22 years old, can't afford a new one, so I keep it rolling as long as I can, everyone is challenging the government these days, and 420 definitely has something to do with the government, and I don't believe it would ruin our world to get past this code, so I agree with all the 420s out there, if my car last me two or three more years I can keep on working and paying taxes as I've done for the last 45 years

[@williamnagel2654]

it's a pos

[@aMartianSpy]

Waste of money.

[@inktheghost]

You talk to much about no topic stuff man. I’m already out

[@bthompson1767]

Get to the point of the video

[@HouseCallAutoRepair]

A few friends with these (all 1.8t) they're challenging... 15mm & 16mm everywhere... and tons of TTY bolts.