B7 s4 running rich

[Koopsdeville]

Hello all. I'm new to this and this will b my first post. Thx for having me. Ok so I'm having issues running rich. Codes p0175 and p0172. Initially I only had the 175 code but Audi told me one of my o2 sensors was dead so now I'm getting both banks rich. I've had this issue for a long time now and I'm starting to get frustrated. I need help pls. Any suggestions would b greatly appreciated. Things I've done so far:
- vacuum test done, no leaks
- replaced fuel filter
-replaced maf and adaptation
-replaced coolant temp sensor
-replaced pcv valve
-replaced coolant tank reservoir(was cracked, possibly N/A)
-replaced 3 of 4 o2 sensors ( pre cat bank 1 not replaced)
-gutted my pre cats since diagnosis turned up pre cats were getting blocked
-installed defoulers I main cats
I've replaced alot more stuff just can't think of it right now. I even tried sea foam. Doubt that helped. I've replaced the plugs but had to take em back out and ended up putting my old ones back in which still looked good. Reason why is I bought the Bosch ones from Audi and the car did not like them. I'll b buying a new set of NGK plugs soon. I should add Im having an extended cold start and rough cold idle. My next step is replacing plugs, oils and filter(Audi told me excessive smell of fuel in crankcase thus pcv was replaced) and changing fuel pressure regulator. I have one question. The o2 sensors didn't have adaptation done. Does the ecu do it on its own or do I need to get this done? Thx in advance



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[Aok303]

Dude your in the same boat as me b7 s4 running rich!!! it's most likely a leaky Injector that is not throwing a bad injector code but staying open enough do dump Fuel, i am about to get some borrowed injectors to find this out.
i should mention that even though i am getting both codes, after having more then one person look at it one bank is crazy over and the other is barley over balanced limits, they said the other side is correcting for 1 bank being over so much as a back up to not blow the motor.

i did the same new maf, leak down, i have newer pcv, evap, gas cap, all o2 sensors checked out, new NGK, i have piggys with the 91 JHM tune.

if your having a slight issues with idle is probably the Check valve if you dont find a leak, as there is a revised part, and if its bad it does causes slight bubble on start up goes away after a min or 2 or if you run hard when you stop at idle it take a min or two to go back to perfectly normal from slight bubble. i was having this issue and this fixed it
the ECU should adapt for the 02 sensors you just clear all the codes and it takes up to 50 miles mixed driving for the car to set up

im pissed though the car runs and drives perfectly fine except the rich codes and i cant pass emissions due to they just ob2 scan and a check engine code is a direct fail

[QIKRNU]

Check out http://www.mrinjector.us/

I bought an injector rebuild kit for my S4 Avant for < $40.00 shipped last year.

[Koopsdeville]

Well I had Audi look at it and they said the injectors check out. As for the check valve, I really don't know what that is our where it is. Could b worth looking at. I'm surprised ur running rich with the jhm tune. I was told it would get rid of such issues. Audi also tells me to change my oil now since my o2 sensors not working would've dumped excess fuel into the crankcase. My acceleration has dropped a bit since this issue started which sucks cause the thing is a pig on gas and the whole reason I bought it was because it was so responsive. Tomorow I'll b changing my plugs, oil and filter and fuel pressure regulator. I'm hoping this changes my situation. I'll keep u updated

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[Koopsdeville]

Qikrnu, I have an extended warranty which covers injectors but so long they diagnose them to b ok I won't b able to get them replaced under warranty. I'll check out the link tho. Much appreciated

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[Aok303]

if you have an extended warranty why is Audi not fixing the car?
I've been doing more reading and our Injectors have been issues to running rich while still passing Vag check,
after you fix all you have listed run a can of bg 44k

the check valve is easy to replace and find the small return air tube that goes into the main intake tube between the MAF and throttle body leads to the Check valve mine would come apart in two pieces. leaking enough to cause small idle blimps at time but not enough to throw a code or even really fail a leak down test. there is a revised part

[S4bro]

Dude your in the same boat as me b7 s4 running rich!!! it's most likely a leaky Injector that is not throwing a bad injector code but staying open enough do dump Fuel, i am about to get some borrowed injectors to find this out.

I suspect my injectors as well. Would love to know your diagnosis.

I am thinking of ordering the remanufactured injectors from rockauto.

[Aok303]

I suspect my injectors as well. Would love to know your diagnosis.

I am thinking of ordering the remanufactured injectors from rockauto.

waiting on an order of those stupid plastic parts on the injectors and gonna see where it leads one bank is like -27 causing the other side to be at -10/11 which is just barley rich but compensation for the other side.
ill post up when we do a lil musical injector swap!!!

[Koopsdeville]

Thx for the heads up about the check valves. I know what u mean about that little blip at idle. I've felt that in every Audi I've owned. My warranty is with lubrico and apparently Audi doesn't do work under lubrico warranties. Only way is to pay for it and ask lubrico to reimburse me buy that's taking a risk at maybe not getting reimbursed. Speaking of bg44k they don't sell it in canada. I could order it online but at this point not sure it's worth it cause I've had my fuel injectors professionally cleaned already. Seriously running out of ideas

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[Koopsdeville]

Although for the record, Audi did check my injectors and they said all checked out but they did also say that usually they would check injectors on a cold start because that's usually when they would leak.

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[Aok303]

Do you have vag com to run some logs? to show us the data of the richness

[Koopsdeville]

I actually haven't bought one yet. Although I would like to but my comp crapped out on me so that would mean investing in a new laptop as well. I can tell u that up until this morning I was running rich on both banks. Now I'm running rich only on bank 2. P0175 or p1129. What changed this is i replaced my plugs yesterday . The old ones looked pretty fouled. I still have them for reference and labelled what cylinder each came out of. When I saw they were fouled I kind of suspected sea foam because I never swapped em out after running a treatment which btw I didn't get any smoke whatsoever. I can say that at cold start up the whole driver side exhaust seems to b rumbling. Does anyone know of a good Audi diagnostic shop? I'm at the end of my whits here

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[Koopsdeville]

On a side note, I couldn't locate my fuel pressure regulator yesterday and neither could the mechanic. He pulled up the diagram of my motor and apparently I have a different fuel rail. Im not sure what to make of this

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[TarlCabot]

B7 have the fuel reg built into the fuel filter... that is why they are so much more expensive

[Koopsdeville]

Oh wow! I hope the one the shop replaced has one in it. I mean it has to right? I don't remember what it cost but I don't think it was cheap for a fuel filter.

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[Koopsdeville]

Actually come to think of it, and maybe ur right, but I spoke with an Audi tech foreman and he never said it's in the fuel filter. Even so I bought my filter straight from Audi. Plus I had the fuel regulator priced out at Audi and it was a separate part. I dunno. I think I just convinced my warranty shop to change my injectors. I should know by the end of the day

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[TarlCabot]

there are two different fuel filter/regulators for the 2004 - 2008 Audi S4, one is a 3 line, the other is 4 line... Not all Audis have the regulator built in to the filter and not all years of the S4 had it

he could have giving you the part #s of the two different fuel filter/regs

iirc both the 3 and 4 line fuel filter have them built in.... that being said, ive also heard the cheaper of the 3 line version is more likely to fail... just as with the pcv, don't go the cheap path... they fail very often

[TarlCabot]

your case really sounds like a faulty fuel injector... hopefully, this will fix your problem

[Aok303]

keep us updated!! i truly hope you get it solved soon i know how aggravating this process is as im still doing it too
if you cant get bg44k Chevron Techron Concentrate Plus Fuel System Cleaner is great and very easy to find ussally!!!, Bg44k is in alot of truckparts and e85 places as it works great with those

[Koopsdeville]

I remember the filter I got was the 3 line. If it has a regulator in it, I wouldn't know but I did buy it from Audi so I'm assuming it's not cheaply mad or atleast I hope not. I had to leave my car at the shop over night. Apparently they started taking the car apart and it didn't make sense to put back together just yet as they were still trying to find the culprit. In the meantime I'm stuck with a civic for a rental. Something my sister would drive. I honestly don't have high hopes. Every time I change something or fix something I end up getting let down with that damn engine light. Anyways my update will have to wait until tomorow atleast. Thx for the well wishes and input. Best of luck to u fellas as well.

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[Koopsdeville]

So an update as of this morning. Just got off the phone with the mechanic. They've pulled off all my injectors and now r waiting on my new injectors. So what he said is the seal around them were very brittle which in turn was probably giving me a vacuum leak which would make it run lean then the injectors would compensate for the lean making it run rich. I'll have it by the end of the day I hope or so he says. Once I drive it, I should know if that fixes the issue or not. Will def keep u guys updated

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[TarlCabot]

So an update as of this morning. Just got off the phone with the mechanic. They've pulled off all my injectors and now r waiting on my new injectors. So what he said is the seal around them were very brittle which in turn was probably giving me a vacuum leak which would make it run lean then the injectors would compensate for the lean making it run rich. I'll have it by the end of the day I hope or so he says. Once I drive it, I should know if that fixes the issue or not. Will def keep u guys updated

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make sure they change the pintle caps as well as the fuel injector orings... they DO get brittle and crack/leak

[Koopsdeville]

Ya that's what he said was already deteriorating which was probably giving me a vacuum leak.

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[Hooblah]

Are pintle caps available from Audi or is it JHM only?

[TarlCabot]

Audi has them OEM... JHM has something similar that works as well... best be prepared, anytime you pull the fuel rail, you will want extras just in case of both the o-rings (standard on pretty much any injector) and the pintle caps that keep them from falling off or getting sucked down into the manifold...
these are so cheap, why not ?

[Koopsdeville]

So injectors were put in today. About 80 kms later that damn light is back on. I'm at a loss of words. Mechanic said to try a reflash. Any input?

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[Hooblah]

I think your best bet is to get it on vagcom and do a log of all the sensor readings. Try to find another to compare against.

[Koopsdeville]

Ya that does sound ideal....

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[Aok303]

new injectors or old ones with new seals n caps

[Koopsdeville]

New from audi

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[Koopsdeville]

Audi said they'd do another diagnostic free of charge since what they told me what the cause was the first time didn't solve the issue

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[Aok303]

oh man i feel for you for everything that has been done for a rich running issue i do not see what else it could be.
lets us know what they say.

i did data log runs from second gear to kinda narrow down further where my rich issues maybe

[Koopsdeville]

Well for the record I spoke with the Audi tech foreman today. He said it could b egr valve or fuel pump. To me I would assume that would b for both banks but I can't b sure. Tomorow morning I have an Audi specialist that's gonna run logs for me and figure out the issue. He's positive he'll find it. Only charging me $40 for the diagnostic and if I repair with him he'll wave it. I thought that sounded fair. I'll keep u guys in the loop in case this could b an issue that u could b having as well

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[Hooblah]

Time and time again I see people throwing money at expensive parts and labour which may or may not solve their problems. Why do people not get a proper diagnosis in the first place? It may be more effort at times but it saves a shitload of time and money.
I can understand replacing o-rings and pintle caps as an air leak could genuinely be the cause, but to replace the injectors on a whim without even testing them is just ridiculous. And now to consider replacing the egr valve and fuel pump... you're just pissing in the wind. May as well call a witch doctor and be done with it.

I guarantee you have an electrical related issue. A sensor somewhere is putting the readings out. My first guess would be the coolant temp sensor, followed by the lambda sensors (o2 for you yanks). I know you've already had these replaced but it's not unheard of for new parts to be faulty out of the box. And make sure you use genuine parts, sometimes pattern parts can cause issues.

[Koopsdeville]

Pissing in the wind? Did u read my earlier posts? There's nothing wrong with changing injectors especially when they're fully covered by warranty. I've already replaced the coolant temp sensor and ur lambda sensors (o2 sensors for us Canadians as well) to assume that all these parts r faulty would b pissing in said wind. Witch doctor? Y do ppl insist on being dicks about something that's already aggravating to begin with? Egr and fuel pump were suggested by Audi. Am I to assume they don't know what they're doing? Or maybe they're the so called "witch doctors?" Maybe it's electrical or whatever, I don't know thus y I'm going thru all the loops to figure it out. I had logs run today and it's the egr valves(I have 2) or I think Audi calls them combi valves or something. On a side note I filled up with petro 94 octane instead of shell 91(Audi recommended) and the light hasnt come back yet.

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[jakeoboy67]

Time and time again I see people throwing money at expensive parts and labour which may or may not solve their problems. Why do people not get a proper diagnosis in the first place? It may be more effort at times but it saves a shitload of time and money.
I can understand replacing o-rings and pintle caps as an air leak could genuinely be the cause, but to replace the injectors on a whim without even testing them is just ridiculous. And now to consider replacing the egr valve and fuel pump... you're just pissing in the wind. May as well call a witch doctor and be done with it.

I guarantee you have an electrical related issue. A sensor somewhere is putting the readings out. My first guess would be the coolant temp sensor, followed by the lambda sensors (o2 for you yanks). I know you've already had these replaced but it's not unheard of for new parts to be faulty out of the box. And make sure you use genuine parts, sometimes pattern parts can cause issues.

I call this the parts cannon method , It can work sometimes (If you're lucky it costs less in parts lol)

OP, was the last O2 sensor replaced ? (your first post says 3 of 4 were new )

[TarlCabot]

that would be awesome to get them to pay for a new egr and fuel pump too, thankfully you have these incompetent mechanics just throwing all these new parts in there... hopefully they will eventually figure it out ;)

[Koopsdeville]

Well egr and fuel pump r covered by warranty. Egr's r the culprits. Most likely just dirty. The weird thing is I've switched to petro 94 and the light hasnt come back. Over 200 clicks and no cel. Will probably just clean the egr's since they're $250 each and even tho they're covered, logs don't show they r faulty but some old European specialist swears after doing logs that they r the issue and hes a 100℅ sure. On the other hand I never noticed but my warranty covers o2 sensors so I can probably b reimbursed for the ones I replaced. And yes only 3 of 4 were replaced. Probably should replace the 4th

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[Aok303]

did you fix your issue

Mine ended up being the Fuel filter and quick clean of the injectors

only reason they knew about the fuel filter is they just had a head ache case of a b7 s4 and finally came down to the fuel filter to run rich

[Koopsdeville]

Hmm I changed my fuel filter... My cel is gone. The last things changed were the injectors and kombi valves. I also switched to 94 gas and haven't seen my cel in a few weeks. My only issue now is a cold start shake on bank 2 until secondary air pump kicks in. Not sure what to make of that tbh

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