Official introduction and first problems

[sCeRaXn]

Hows it going people. I just bought a 2000 s4 6spd earlier today so i thought id introduce myself. Ive been looking for a new(to me anyway) car and there were a few things i had to have...4 doors, turbo, and awd. I looked at Evos and Sti's, but they just seem to boy racer to me now. Dont get me wrong...theyre awesome cars and i still love them, but im out of "that" stage now and wanted something with a little luxury. The s4 was the obvious choice at this point. I looked at a few others and wasnt happy with the price and/or lack of service records. I finally found a black s4 that was pretty local to me so i went and checked it out. It has excellent service records and its inr eally good condition despite the high mileage(150k). It was a lease car for 4 years then it was bought by an old man. He used it to drive from Kernersville to Atlanta two times a week...so theyre mostly highway miles. This, along with the fact that this was the ONLY stock s4 i could find in the tri-state area made it perfect for me.

So im driving it over to a friends house to show him the new money pit...and while accelerating onto the highway the car suddenly feels like it loses some power and the CEL pops on. It still drove fine, except for the fact that in higher load situations it felt like it was hitting boost cut or something. It all seemed to happen around 3krpms. I just ordered a vag-com so ill be able to use it to read the code(if i can figure out how to use it lol), but id like to be able to figure it out and fix it before the vag-com gets here. Any ideas on what it could be? What are the limp mode symptoms on these cars? After the CEL came on the car would still rev to redline so i dont think i was in limp mode at that point. It just felt like it didnt have any power...and it was almost like the turbos got louder after it happed. This made me think it was a boost leak, but i dont think that would cause it to throw a code would it?

Tomorrow im gonna tear into the car and check everything over, so i guess ill see if it was the tbb(i dont think it is though). Is there any way to check the DV to see if its still operating properly? Im sure i can do it with a vac gun, but i dont know if theres a certain way of doing it on these cars.

Any and all help would be greatly appreciated. And if anyone in the triad area(NC) has a vag-com that i can use ill throw you some cash for it. Sorry its so long and ill go ahead and apologize for it being so jumbled...i have some family in town and were having the typical Irish family gathering...lots of food and LOTS of alcohol lol

[NOVAS4]

same thing happend to me when my MAF was no good.... when ever you try to boost it falls on its face or can your boost?

[sCeRaXn]

Its sorta hard to tell if im boosting because i only had it for an hour or so before the CEL lit up lol. I think its seeing some boost, but it just doesnt feel as peppy as the first time i got on it during the test drive. Like i said, its almost like its running lower psi and hitting the boost cut. I experienced this on an FD and it turnout to be a coupler that was slightly ripped and only leaked under boost...but i just dont think thats the problem here since it threw a CEL.

Im about to go out there in a few and mess with it to see what i can come up with. I know this is a stupid question, but can any scan tool read the codes for me? I have a buddy with a nice one and im thinking about riding over there to see if i can figure out what codes its throwing. If not then ill just go to auto zone or something and see if the can scan it for me. I really hate doing that though because i do NOT trust those people to mess with my car. I really dont trust anyone to mess with it, thats why i went to school for auto tech lol.

BTW-Is there any way i can check the MAF to see if its causing the problem? I have a multimeter but i dont know of the procedure for checking it on an s4. I know these questions sound stupid, but im very meticulous about things and try to know EXACTLY what im getting into before i start.

[obijohn22]

limp mode in these cars will cut to 5 psi max boost. this could be caused by many things, overboosting because of a bad n75 valve, or severe misfires, etc. it doesn't sound to me like a boost leak, because of the cel. but any how the first thing to do is read the codes. good luck and welcome to the family. also keep us posted so we can a ll learn from this!

[sCeRaXn]

So limp mode only reduces the boost and doesnt affect the redline or fueling/timing? Thats pretty cool because most other turbod cars ive owned have decreased redline etc while in limp mode. Im trying to get in touch with a friend of mine to see if i can use his scan tool...if not then ill go to auto zone and see if they can do it for me.

I just went out there and checked things out and the TBB isnt torn...in fact it looks brand new. Are n75 valves the DV's? I looked at mine and they were Bosch units that had a 208 part umber. Is there any way to check these valves to see if theyre functioning properly? I assume itll be like testing any other vac/boost regulated valve and you can do it with a vac gun? Sorry for all the stupid questions, but im new to the Audi world so it might take me a while to get things down. Ive learned the hard way that testing something on one car can be COMPLETELY different than testing the same part on another car, and can possibly cause alot of damage. So im just trying to cover all my bases before i tear into it. Ill be sure to post up my findings when i figure it all out. Thanks again for all the help, and keep it coming if you have any other ideas.

[mrpeterparker]

you can do a pressure test .. to look for leaks... it's not a problem...

the DV's are the bosch ones you found. those are something you should replace with either 710N's from the audi TT or upgraded aftermarket ones.

also.. when checking the TBB... take it off the car.. and inspect it... you'll never see the tear if it's still seated on the engine

[obijohn22]

the N75 valve operates the wastegates. DV valves vent boost like a bov when returning to vacuum after being on boost. they just return it to the intake as it is already metered by the maf. A lot of other turbo cars have pre maf BOV's which just vent to the atmosphere. If you have the stock bosch Dv's they will be 710a's, the 710n valves are much better and very durable. about 35-40 bucks each.

[mholme]

Sounds like you did some good research of the basics before buying the car. You'll need to build a pressure tester to go along with your VAG-COM. They will become your two best friends. The diverter valves can be tested by pushing up on the diaphragm with your thumb and then covering the vacuum nipple with a finger. The diapraghm should stay raised as long as you hold have your finger over the nipple. If it starts to close with your finger in place, the valve is bad. Good luck, these cars are great once you get em sorted.

[lrg8683]

throttle body boot----check it

[KompMan420]

I certainly think your car is in limp mode. This can happen for way too many reason so check the codes at autozone and report back. We'll go from there, but without that info everything is speculation and could have you chasing your tail.

FYI, DV's do NOT vent. They recirculate or "divert" the boost pressure. BOV's vent. It's the difference between a closed system (like all turbo VW, Porsche & Audi) and an open system (STi and EVO)

[mholme]

throttle body boot----check it

also.. when checking the TBB... take it off the car.. and inspect it... you'll never see the tear if it's still seated on the engine

Yup, it needs to be removed. Not just a visual on car inspection. Mine ripped right under the clamp. I would have never seen it without taking it off.

[Reich]

Does 2000 s4 used to have bosch maf instead of mitsubishi? It might be maf, but everybody's right. Younead to know what f/c you have.

[sCeRaXn]

I took the tbb boot off earlier and it looked brand new...but you can see a few small stress points directly under the screw portion of the clamp. Ill replace it with Samco or something else in the future, but it seems fine for right now. Ill check the DV's later, but it doesnt sound like that would be the problem either. As for the n75 valve...is this a valve that controls the opening and closing of the wg actuator? Where can it be found in the bay, and how can it be tested? I hate having to ask so many "newb" questions. When it comes to Hondas, 240's, FD's, supras, srt's, and Sti's i can pretty much tell you where every single sensor and valve is located and what they do...but i havent quite figured out this Audi stuff yet lol.

I went to my friends house a little while ago, but his scan tool wouldnt read the codes for some reason. Like an idiot he disconnected the battery and reset the ecu...so now im gonna have to wait until the light comes on again before i can find out what code its throwing.

Anyone know the pinout for the stock MAF? And what the values are supposed to be? Ive been searching high and low and i havent come up with anything. I went to 7 different auto parts stores today to get a Haynes manual...but nobody has one. If someone has one and can help me out id greatly appreciate it.

[sCeRaXn]

I guess i should go ahead and give my impressions of the car. I meant to do it in the original post, but i was pretty buzzed when i wrote it so it must have slipped my mind lol. Basically, i absolutely love the car. Ive owned and driven countless performance cars, both stock and modified, and i have to say that this is one of my favorite cars so far. Its not close to being the fastest or best handling car ive owned...but overall the car is amazing. Its beautifully balanced power delivery and handling make it a blast for spirited driving, and combined with the luxury it provides its really hard to beat.

Its my DD so im not gonna push it too hard. Ill probably do the typical stage2 bolt-ons and a decent wheel/suspension setup and leave it alone. I also own a 90 crx thats about to become and all out drag car(again), so most of my spare money will be going towards it. For now...im just going to enjoy the amazing experience of driving this beautiful car!

[bigverge]

Its my DD so im not gonna push it too hard. Ill probably do the typical stage2 bolt-ons and a decent wheel/suspension setup and leave it alone. I also own a 90 crx thats about to become and all out drag car(again), so most of my spare money will be going towards it. For now...im just going to enjoy the amazing experience of driving this beautiful car!

If I had a nickle for every time I heard that haha. You will spend way more than you think now. After all stage 3 is more reliable than stock anyways!

[mholme]

I also own a 90 crx thats about to become and all out drag car(again), so most of my spare money will be going towards it.

"Spare money" and S4 ownership don't usually go hand in hand buddy..but I'll let you find that out for yourself...

[TalipseAWD]

Your on HT.
<---RoorOwns on HT
Nice Buy, Would sold you mine with only 105k....

[sCeRaXn]

If I had a nickle for every time I heard that haha. You will spend way more than you think now. After all stage 3 is more reliable than stock anyways!

HAHA yea thats how it usually happens. If i spend more on it than i plan itll probably be to fix things instead of adding performance parts. If the clutch or turbos go then ill just have to spend the extra money for k04's and aftermarket clutch, but theyll stay stock for now...hopefuly lol

[sCeRaXn]

Your on HT.
<---RoorOwns on HT
Nice Buy, Would sold you mine with only 105k....

Yea im on HT, but the only reason i go there now is for the MMA thread lol. Between work and training i dont really have the time to get online much...but ive been making time since i got the Audi. These cars are addicting!

[TalipseAWD]

Yea im on HT, but the only reason i go there now is for the MMA thread lol. Between work and training i dont really have the time to get online much...but ive been making time since i got the Audi. These cars are addicting!

<--GDD whore.
Have fun with the car.
Just have patience, I've had mine for a year and a couple months and I've spent $2500 on parts and labor and its still stage 1. lol.
Its worth it in the end.

[sCeRaXn]

<--GDD whore.
Have fun with the car.
Just have patience, I've had mine for a year and a couple months and I've spent $2500 on parts and labor and its still stage 1. lol.
Its worth it in the end.

HAHA yea GDD keeps me entertained when im bored. I actually think HT has one of the better GDD forums out of all the car sites im involved with. But yea having a high hp honda has showed me a new meaning to the word "patience". It was one thing after another with that car...but ive had it for 8yrs now and ill probably have it til the day i die lol.

So tonight i was coming home from a show and the CEL lit up again...but this time the car continued driving normally. I didnt boost it hard, but it still had all its normal pep. So i guess im gonna go to auto zone tomorrow to see what they have to say. Hopefully they will just tell me the code and let me do the rest of the trouble shooting. When they try to do it things turn out bad.

Oh yea, the screen on my gauges decided to start working again tonight...until i turned the car off and back on. Then it went away again haha. Oh well i finally got to see my average mpg, which is better than i expected at 24.5. I talked to a friend who also owns a 2000 s4 and he said that this is a major problem with these cars. He had his replaced 5 times under warranty...which is absolutely retarded. I really dont want to spend the money to replace it when it might go out again in a few months. Has anyone came up with a permanant cure for this? He also said that there was talk of a class action lawsuit about this a while back...whatever came of that?

[sCeRaXn]

So i just got back from Auto Zone and im throwing a code p0421...which means the catalytic converter on the #1 bank isnt working effeciently. I went through this with my friends 03 Cobra and it gave us a fit(turned out to be a bad spark plug), so i remember that code perfectly lol. So now that i know whats wrong, i need to start the process of fixing it. I looked under the car and saw that the cats are part of the dp...which sucks because i dont want to spend the money on a new dp right now. So im probably gonna cut out the old one and weld in another, or just gut them all and make some piggies. Im just happy that it wasnt something major considering the fact that ive only had the car for 2 days now lol.

Thanks for all the help guys. I was actually surprised that i didnt get flamed out the ass for asking all the newb questions. It looks like i might have finally found a car site that isnt full of pompous pricks lol! Ill post results when i get around to fixing it.

[KompMan420]

The problem isn't your cat. It's your O2 sensors. Replace them with the ones from VAST Performance.

[sCeRaXn]

The problem isn't your cat. It's your O2 sensors. Replace them with the ones from VAST Performance.

You think so? Alot of people ive talked to and alot of threads that ive read say that the cats are known for going bad. Do you have any idea which ones would be bad? Im guessing the fronts since the code is technically for the "warm up cats", so the front 02's would be the first to try and read it? This is just a guess so stop me if im wrong lol. I dont really want to spend $430 for all 4 sensors if they arent all bad.

BTW-Is there any particular reason to get the ones from VAST?

[mholme]

You think so? Alot of people ive talked to and alot of threads that ive read say that the cats are known for going bad. Do you have any idea which ones would be bad? Im guessing the fronts since the code is technically for the "warm up cats", so the front 02's would be the first to try and read it? This is just a guess so stop me if im wrong lol. I dont really want to spend $430 for all 4 sensors if they arent all bad.

The O2's only read the warm up cats, not the main cats. They take readings from upstream(front) and downstream(rear) sensors. I believe the rears are what send the reading to the ecu, but changing my front O2 got rid of the warm up code I had. This was before going piggie pipes. I've since had to put non foulers in the rear sensor locations to keep the warm up codes from coming back.

[sCeRaXn]

So getting new front 02's and putting non foulers on the rears will cure the problem? I was planning on doing the piggies soon anyway, so ill just relocate the rears and use the non foulers to keep the code from coming back. I hope this cures it because itll be cheaper than buying all 4 sensors and itll give me a little extra power.

Thanks for the info!

[mholme]

So getting new front 02's and putting non foulers on the rears will cure the problem? I was planning on doing the piggies soon anyway, so ill just relocate the rears and use the non foulers to keep the code from coming back. I hope this cures it because itll be cheaper than buying all 4 sensors and itll give me a little extra power.

Thanks for the info!

I'm saying after logging my O2's, my driver side front was out of spec. I replaced it and the CEL went away. After gutting the pre cats, the O2's would have not registered a difference from upstream or downstream readings and thrown a code. That's what the anti foulers do on the rear, take the sensors out of the exhaust stream. If you relocate the rear O2's behind the main cat with piggies, you shouldn't need the anti foulers. If your O2's are original, you may want to get some readings from them with a VAG-COM and see what comes up.

[KompMan420]

You think so? Alot of people ive talked to and alot of threads that ive read say that the cats are known for going bad. Do you have any idea which ones would be bad? Im guessing the fronts since the code is technically for the "warm up cats", so the front 02's would be the first to try and read it? This is just a guess so stop me if im wrong lol. I dont really want to spend $430 for all 4 sensors if they arent all bad.

BTW-Is there any particular reason to get the ones from VAST?

Chances are, you're going to end up replacing all 4 eventually. What you really need is that VAG-COM so you can say with certainty which pair you need to replace now and which pair can wait. If I had to guess, I'd say the front set need to go, but be sure before you go spending money.

VAST Performance O2 sensors use OEM sensors, but are built WAY better than stock replacements. I put all 4 on my car from them. Plus, Mike @ VAST is awesome to work with!

Dunno if anyone asked or if you mentioned it, but how many miles are on the car?

[mholme]

Dunno if anyone asked or if you mentioned it, but how many miles are on the car?

He's got 150k on it. Mine were on there way out after 75k miles.

[KompMan420]

150k miles on original O2 sensors is A LOT. Change 'em for sure.

[sCeRaXn]

Chances are, you're going to end up replacing all 4 eventually. What you really need is that VAG-COM so you can say with certainty which pair you need to replace now and which pair can wait. If I had to guess, I'd say the front set need to go, but be sure before you go spending money.

I ordered a Vag-com on saturday, so i guess ill find out which ones are bad when it comes in. My money is on the fronts as well, but like you said...i dont want to spend the money if i dont have to. Ill just wait and put them in when i do the piggies in a couple weeks. Now i have to get some DV's as well. I checked them out yesterday and the one on the right bank was stuck. Anyone know of a place to get the 710n's for cheap? Vast wants $99 for both of them, but i keep hearing people say you can get them for $30-$35.

I also noticed that there was alot of oil in the DV and inlet pipe on the left bank, but none at all in the right. Im actually more concerned that there isnt any oil on one side. Every turbo car ive owned has had oil in the piping, except when a turbo blew. I guess ill have to wait until i fix the DV's to do the pressure test? Well i guess it really depends on how its done on these cars. If its done on the y-pipe for the intake i could probably still do it since the DV is downstream from that point, and the pressure between the bi-pipe and y-pipe would equalize. Oh well, ill probably look for a write up on doing it and try it out sometime this week.

BTW-The 02's on the car now say mexico on the side, so theyve obviously been replaced at some point. Im assuming that Bosch makes the OEM sensors for this car? The guy before me probably replaced them with cheap stock replacements from auto-zone or something.

[mholme]

710N's are like 40 bucks a pop new, cheapest I've seen anyway.

http://www.awe-tuning.com/media/pdf/...ure_tester.pdf

Instructions for the pressure tester

[sCeRaXn]

710N's are like 40 bucks a pop new, cheapest I've seen anyway.

http://www.awe-tuning.com/media/pdf/...ure_tester.pdf

Instructions for the pressure tester

Thanks for the instructions man. Where have you found the 710n's for $40...the dealer or online? I just did a quick search on ebay and nothing came up, but ill probably keep trying there until i see a good deal.

[mholme]

Thanks for the instructions man. Where have you found the 710n's for $40...the dealer or online? I just did a quick search on ebay and nothing came up, but ill probably keep trying there until i see a good deal.

genuinevwaudiparts.com

[KompMan420]

A pair of 710n's from VAST is $88.50. I just bought a pair from them about a month ago and they were the cheapest.

Also, FYI, you won't find a Haynes manual like most cars. Bentley makes the repair "manual" for our cars and it comes on DVD ROM.
http://www.bentleypublishers.com/product.htm?code=ab55

[KompMan420]

I just searched that genuinevwaudiparts.com site for 30 minutes and couldn't find a single DV for an S4 or a TT. What a shitty site...

[mholme]

I just searched that genuinevwaudiparts.com site for 30 minutes and couldn't find a single DV for an S4 or a TT. What a shitty site...

You gotta search by part number...06A145710N

[sCeRaXn]

A pair of 710n's from VAST is $88.50. I just bought a pair from them about a month ago and they were the cheapest.

Also, FYI, you won't find a Haynes manual like most cars. Bentley makes the repair "manual" for our cars and it comes on DVD ROM.
http://www.bentleypublishers.com/product.htm?code=ab55

I figured they would be the cheapest, i was just making sure i couldnt get them for cheaper. I dont mind spending money on better parts, but i still like to find the best deal possible on those parts lol.

Thanks for the link to the "manual" . Sucks that it isnt a book, but beggers cant be chosers. They really do come in handy...especially with wiring diagrams, sensor specs/parameters, and torque specs. If i had one i wouldnt have to be asking all these stupid questions lol.

[KompMan420]

^^ True, but you can't type in a keyword search in a Haynes manual and they don't have updates, tech bulletins and pictures of naked playmates... ok I made that last part up, but you get the idea.

[sCeRaXn]

^^ True, but you can't type in a keyword search in a Haynes manual and they don't have updates, tech bulletins and pictures of naked playmates... ok I made that last part up, but you get the idea.

LOL so it doesnt come with pics of naked chicks? That blows!

The search feature would be badass though. The only reason i prefered the book is because if i want to look up something while i was working on my car id have to wash my hands so that i dont gunk up my computer. But i can just wear gloves...and the extra features on the Bentley one would probably outweigh the downfalls.

So i just got an email from my friend saying that he cant get me that vag-com...so im searching for alternatives. He says that hes used one from Ebay and its just as good as the expensive ones. Anybody have any experience with these? He works on Audis/VW's all the time so i trust his judgement, but it would be nice to have some people back up these claims. It almost sounds too good to be true...a $10 part doing the same thing as a $200+ part? Does ssac make it or something lol.

Heres a link to the one hes talking about
http://item.express.ebay.com/USB-KKL...mdZExpressItem