Fuel smell in cabin??

[AudiTFSI3o3]

Hey all, has anyone gotten the smell of fuel vapors in the cabin before? I've been chasing this bug for over a month and today is the 3rd time it happened. I've replaced the lpfp and had a shop check for any fuel leaks in the system, lines, anywhere and they said everything is fine. I'm completely lost.

Long story short, started experiencing fuel cuts last month while over in Vegas, followed with "low fuel pressure and fuel pressure regulation" codes AND fuel smell inside the cabin. The car even stalled out about 10 times driving back to Denver. When I got back, bought a brand new lpfp (in-tank) and replaced that. So far I haven't had any problems of it coming back and there are absolutely no visible fuel leaks anywhere.

Today we had a Dyno day. Car went on the Dyno twice (first and last runs of the day) and it was making less power than it should (best run was 340whp/325wtq while 3.0t Q5 with the exact same setup was making 362wph and 350 or so wtq). Driving home I started getting the fuel smell again and it's STRONG. Scanned it, no codes, everything seems fine.

Anyone have any idea what it could be?

[AudiTFSI3o3]

just a little bump for anyone following this.

seems like i'm getting the fuel smell from the front driver's side. as mentioned before, nothing is actually leaking, seems like only vapors are venting out somewhere. i've searched older threads from 2010 and it seems like could be a failing fuel rail (most likely driver's side FR) or bad seals on the injectors. I'm currently trying to source a used set of rails and injectors since they go for around $100-$130 each brand new.

Will update

[waxxonMTL]

I'm having the same issue.. but right after doing the walnut blasting.. I'm sure the mechanic didn't screw it back correctly or popped an injector seal.

[jimrobbington]

What's up Joe. I had a slight fuel smell when I bought my S4. Dealer found something on the fuel rail on one bank was loose, and they had to tighten maybe replace something. Doubt that helps, but that's what I got. Lol

[AudiTFSI3o3]

What's up Joe. I had a slight fuel smell when I bought my S4. Dealer found something on the fuel rail on one bank was loose, and they had to tighten maybe replace something. Doubt that helps, but that's what I got. Lol

thanks John. I actually called around and there was a recall for the fuel rails I think up to MY2012, unfortunately for me my year doesn't apply. I've made an appointment with Prestige next week to see what we can find, hopefully everything can be covered under warranty and I won't get flagged lol.

[AudiTFSI3o3]

wanted to bump this because every where that i've looked I haven't found an answer. i'm desperate guys, please help.

Since the last update, took the car to Prestige and told them what was going on. They gave me a loaner and kept the car for 3 days. They drove it around and did what they could to try and diagnose it, but wasn't able to replicate the problem with the fuel smell coming into the cabin. As mentioned before, it's intermittent. They told me the next time it happens, bring it in immediately and they'll get to work.

It happened again today but nothing I could do until Monday, if the problem even persists Monday. So when it happens, the fuel smell will come into the cabin while cruising and is the strongest in the front. Even with the windows down it doesn't help. It does seem to lessen when stopped at a light, until I start moving forward again. I've sniffed around every where I could, even opening the door over and over to "prime" the pump to get the smell. I can't pin point exactly where it's coming from, other than from driver side area.

Any help would be greatly appreciated guys.

[LYKUNO]

Sounds like you've done a lot to try and locate the problem, even involving the dealer. Since it happens while the car is in motion, have you tried completely turning the climate control system to the "Off" position, so there's no airflow from the engine compartment into the cabin? Alternatively, have you tried running the A/C in the recirculate mode, so that external air is not getting into the cabin?

Another question, does it matter how much fuel is in the tank when the problem occurs? For example, does the problem happen when the fuel gauge is less than 1/2 full, or more than 1/2 full. Not sure, but isn't there a fuel return line, so that fuel that is pumped from the tank to the engine and not used is returned to the tank via that line. I assume that was checked though.

And finally, here's a tool available on Amazon that might help: the "Tonor Combustible Gas Detector Portable Gas Leak Tester with Sound-light Alarm". According to the description, it "Detects combustible gas leak - Methane, natural gas, coal gas, gasoline, alcohol, ketone and other flammable gases". Features include:
*Detects combustible gas leak - Methane, natural gas, coal gas, gasoline, alcohol, ketone and other flammable gases.
*Flex Probe - 12 inches flex probe with a highly sensitive sensing tip locates leaking spot effortlessly.
*Audible And Visual Alarms - Ticking and LED light indicate concentration levels
*High Sensitivity Sensor - Features high sensitivity sensor that operates in the harshest conditions while experiencing minimal drift and interference.
*Adaptable in various situations - can be used in construction projects, mines, safety check of gas appliances, oil spill and etc.

Here are a couple more that Grainger carries that state they can detect gasoline vapors: Extech and Test Product Intl

[AudiTFSI3o3]

Sounds like you've done a lot to try and locate the problem, even involving the dealer. Since it happens while the car is in motion, have you tried completely turning the climate control system to the "Off" position, so there's no airflow from the engine compartment into the cabin? Alternatively, have you tried running the A/C in the recirculate mode, so that external air is not getting into the cabin?

Another question, does it matter how much fuel is in the tank when the problem occurs? For example, does the problem happen when the fuel gauge is less than 1/2 full, or more than 1/2 full. Not sure, but isn't there a fuel return line, so that fuel that is pumped from the tank to the engine and not used is returned to the tank via that line. I assume that was checked though.

And finally, here's a tool available on Amazon that might help: the "Tonor Combustible Gas Detector Portable Gas Leak Tester with Sound-light Alarm". According to the description, it "Detects combustible gas leak - Methane, natural gas, coal gas, gasoline, alcohol, ketone and other flammable gases". Features include:
*Detects combustible gas leak - Methane, natural gas, coal gas, gasoline, alcohol, ketone and other flammable gases.
*Flex Probe - 12 inches flex probe with a highly sensitive sensing tip locates leaking spot effortlessly.
*Audible And Visual Alarms - Ticking and LED light indicate concentration levels
*High Sensitivity Sensor - Features high sensitivity sensor that operates in the harshest conditions while experiencing minimal drift and interference.
*Adaptable in various situations - can be used in construction projects, mines, safety check of gas appliances, oil spill and etc.

Here are a couple more that Grainger carries that state they can detect gasoline vapors: Extech and Test Product Intl

thanks for the reply I appreciate the response. i'll try to answer everything in the order you asked.

1. yes, when the smell becomes present in the cabin, i'll roll the windows up and down, turn the climate control on an off, no matter what, the smell is still persistent in the cabin.

2. in regards to fuel, the tank level does not seem to affect the problem. at first I noticed the smell coming into the cabin when the tank was less than 1/2. second time it happened the tank was about 1/4 full. BUT the most recent time it happened, I had a full tank. I almost positive this line was checked during the first issue and it came back as normal.

3. thanks for the advice. thats probably the best place to continue searching is with the tool. I'll look into it now

[OmaHahn]

Is it a fuel / gas smell or maybe like a natural gas smell? I don't think this will help but you never know. I own a Ford SHO and there was a recall on the PTU unit. Some of the symptoms are: clunking noise at low speed, loss of power, and weird enough a smell of fuel or natural gas in the cabin! The 4th generation SHO has the twin turbo V6 with AWD using a PTU unit to transfer power. I can't remember how the Quattro system is setup in the B8, but hope I maybe helped.

[AudiTFSI3o3]

^^ it's definitely fuel.

I was looking at the parts catalog for the entire fueling system yesterday. what stuck out to me was the charcoal canister - which is meant to filter out the gas vapors from the gas tank, and re-route them back into the engine to burn off. could a failing charcoal canister or maybe the line that would lead the vapors back into the engine be the culprit? seems the most likely right?

[timzcat]

A charcoal canister is a good source for fumes. But head under hood should pick that up immediately. Send me a link for the fuel system if it is online so I can see the location of components.

Let me ask you this, once it starts you can't get rid of it. So correct me if I am wrong but the tank is probably under the rear seat, have you looked there?
A small leak in the seal there would expose fumes to the interior that won't go away because it right in the interior.

[AudiTFSI3o3]

A charcoal canister is a good source for fumes. But head under hood should pick that up immediately. Send me a link for the fuel system if it is online so I can see the location of components.

Let me ask you this, once it starts you can't get rid of it. So correct me if I am wrong but the tank is probably under the rear seat, have you looked there?
A small leak in the seal there would expose fumes to the interior that won't go away because it right in the interior.

That's the funny part. Whenever the smell is present I'll pop the hood and sniff around the fuel pump and lines closest to it, even the purge valve near the intake tube and nothing. It's when you get towards the driver door that the smell is noticeable which is the most odd. I've even removed the fender liner and there's nothing to do with fuel lines on the driver side.

In regards to the rear seat, the first time I started getting the smell in Vegas I scanned the car and got "low fuel pressure" codes. I immediately replaced the low pressure pump/fuel filter which is located directly under the rear seat. Everything on that end is brand new, and no codes since. Just still getting the smell every now and then. And when the smell does become present I'll even pop the rear seat and sniff around the cover - nada.


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[SwankP3RF3ct10n]

Dude, it's got to be the fuel rails. There's a TSB or recall for it on the B8.5 cars I think. Supposedly affects some VINs but not others, but not sure how much you can really trust that. The info has been posted on here like a year or so ago. Print that out and give that to your service manager and tell them to look again per the documents from Audi.

[AudiTFSI3o3]

Dude, it's got to be the fuel rails. There's a TSB or recall for it on the B8.5 cars I think. Supposedly affects some VINs but not others, but not sure how much you can really trust that. The info has been posted on here like a year or so ago. Print that out and give that to your service manager and tell them to look again per the documents from Audi.

thanks Swank. if you read a few posts up i actually contacted Audi regarding the fuel rail TSB. it only affects certain models from 2010-2012 so i'm out of the range. heck, I even dropped the car off at the dealership for 2-3 days and they couldn't find anything abnormal.

[LittleDozer]

Hopping in this thread to see resolution.

I have had a myriad of fuel issues with my '14 S4. Also stage II. What were the specific codes? P310B is LPFP. Anything else is HPFP side related like P0087.

I get a gas smell when starting the car and the oil usually smells like gas. No codes thrown and car isn't running rich which is odd.

[SwankP3RF3ct10n]

thanks Swank. if you read a few posts up i actually contacted Audi regarding the fuel rail TSB. it only affects certain models from 2010-2012 so i'm out of the range. heck, I even dropped the car off at the dealership for 2-3 days and they couldn't find anything abnormal.

No, that doesn't seem right. From what I remember, it was with the newer B8.5 models, NOT the old B8 models. It happened after the 2013's were out if I remember correctly. The info is on this site, just too lazy to search for the thread about it.

[LittleDozer]

No, that doesn't seem right. From what I remember, it was with the newer B8.5 models, NOT the old B8 models. It happened after the 2013's were out if I remember correctly. The info is on this site, just too lazy to search for the thread about it.

I think it's the 2013 model that was affected then Audi made a fix to all models going forward. So 2014 models shouldn't have the issue since they made the fix before production.

[AudiTFSI3o3]

I think it's the 2013 model that was affected then Audi made a fix to all models going forward. So 2014 models shouldn't have the issue since they made the fix before production.

I believe you are correct. I even asked my SA about any other known issues, and other than the tensioner rattle TSB and airbag module recall, there's nothing else for 14+.

In regards to your other post, when the issue started I pulled codes P0087 - Fuel Rail/System pressure - Too Low and P310B - Low pressure Fuel regulation. Like you said and as mentioned above, I replaced the LPFP along with fuel filter since it's together under the rear seat. Since then I haven't gotten any codes regarding fuel pressure.

Also, are you noticing the fuel smell in hotter temperatures? Maybe it's a coincidence but from what I recall, the 3-4 times that the smell has occurred and escaped somewhere in the system, the ambient temperatures have been 100F and up.

[jimrobbington]

I found my receipt, it says they found fuel rail adapter on bank 1 loose and leaking fuel. Says all they did was re torque the adapter...

[AudiTFSI3o3]

I found my receipt, it says they found fuel rail adapter on bank 1 loose and leaking fuel. Says all they did was re torque the adapter...

thanks John. When you were having the issue, did you notice any fuel smells like what I've been describing? or were you noticing more of actual leaking fuel?

[jimrobbington]

thanks John. When you were having the issue, did you notice any fuel smells like what I've been describing? or were you noticing more of actual leaking fuel?

I never saw anything leak. I only smelled some fuel in the cabin from time to time.

[AudiTFSI3o3]

I never saw anything leak. I only smelled some fuel in the cabin from time to time.

damn, i wouldn't mind just re-torqueing the rail if that's the case, but i'd have to remove the SC to get to the rails. any chance you know if the bolts are reusable? or are they TTY like the rest of the car lol

[jimrobbington]

damn, i wouldn't mind just re-torqueing the rail if that's the case, but i'd have to remove the SC to get to the rails. any chance you know if the bolts are reusable? or are they TTY like the rest of the car lol

Not a clue man, but there where no parts labeled under that section that were replaced. Only line items were for compressor removal and for fuel...no part numbers, so I'm assuming reuse is OK.

[LYKUNO]

Not a clue man, but there where no parts labeled under that section that were replaced. Only line items were for compressor removal and for fuel...no part numbers, so I'm assuming reuse is OK.

Bump - OP: Did you ever get this resolved? If so, what was the cause?

[AudiTFSI3o3]

Bump - OP: Did you ever get this resolved? If so, what was the cause?

thanks for the bump, i haven't gotten anything resolved yet because I haven't really had the issue since. as mentioned before it's intermittent and since my last update I haven't had the problem. i'm traveling right now, I will definitely pull the SC next week and check rails and injectors

[Brother Owl]

Necro bump, hey guys just wanted to update. Got my car back from dealer and they completely replaced HPFP. Tech says they had seen this issue but more common on Q series 3.0t. He also confirmed that a visual inspection around the HPFP showed small signs of dried fuel deposits. No TSB was mentioned but hopefully this helps

[LYKUNO]

Yeah! Glad to hear they found signs of a leak. Hopefully you'll never have that experience again!

[Brother Owl]

Yeah! Glad to hear they found signs of a leak. Hopefully you'll never have that experience again!

It's def nice to grab a beer from the garage and not get high from the fumes...
Wait. I might actually miss that

[AudiTFSI3o3]

It's def nice to grab a beer from the garage and not get high from the fumes...
Wait. I might actually miss that

damn thanks for the thread bump. so they just replaced the HPFP and that was that?

[Brother Owl]

damn thanks for the thread bump. so they just replaced the HPFP and that was that?

Yea man, covered under CPO. My car was stinking all the time recently though, really strong. No intermittent issues like you had, hopefully you're not still having problems

[jygesq]

Necro bump, hey guys just wanted to update. Got my car back from dealer and they completely replaced HPFP. Tech says they had seen this issue but more common on Q series 3.0t. He also confirmed that a visual inspection around the HPFP showed small signs of dried fuel deposits. No TSB was mentioned but hopefully this helps

Did they fix the clunking noise going over bumps? If not it could be plastic bumper stop on hood need to have felt placed on them. It fixed noises over driveway entrances and exits for my car

[AudiTFSI3o3]

Yea man, covered under CPO. My car was stinking all the time recently though, really strong. No intermittent issues like you had, hopefully you're not still having problems

yeah when i dropped the car off at Audi last time, they had the car for 3 days straight and couldn't replicate the problem. Glad you got that figured out though. i'm already out of warranty of any sort so next time if it happens again i'll just try to snag a new HPFP along with other bits!

[Brother Owl]

Did they fix the clunking noise going over bumps? If not it could be plastic bumper stop on hood need to have felt placed on them. It fixed noises over driveway entrances and exits for my car

Thanks, I was thinking ball joint or suspension something but when they said bump stops I knew what they meant immediately. Then they offered to put felt tape on it....... for $100!. I politely declined

yeah when i dropped the car off at Audi last time, they had the car for 3 days straight and couldn't replicate the problem. Glad you got that figured out though. i'm already out of warranty of any sort so next time if it happens again i'll just try to snag a new HPFP along with other bits!

No doubt, hopefully you won't have too. I have CPO so I asked stealership and they wanted $900 for a non-warranty repair LMAO

[jygesq]

Felt tape is cheap, you can get it from auto parts store and cut round circles for bumper stops on hood ( four of them) and do it yourself!

[whiped]

You could probably just service your existing hpfp. Look at my diy for the autotech upgrade for more info.

[Brother Owl]

You could probably just service your existing hpfp. Look at my diy for the autotech upgrade for more info.

Thanks for the write-up whiped, if my new one(free under cpo) goes south I'll tackle it myself

[nicholsB8]

Here for solution. Same issue with 2010 A4 Avant. Fuel smell, but not a single indication of a leak. Kicker is it only smells when there’s over half a tank of gas. Anything below half it goes away.

[AL2.0L]

Just thought I shared my experience with my wife 2009 B8 A4 Premium Sedan. Lately we started smelling gas but it goes away after but this last fuel fill up the smell got really bad when I open my garage smelled like I have open tank inside the garage. I recently rebuilt the engine because of the burning oil (one quart every fill up) and car runs great now so I checked under the hood and nothing is leaking and I don't see any fluid drips in my garage. I decided to check the fuel pump inside the tank which is located under the rear seat and very surprised with my findings. There a was puddle of fuel around the fuel pump and on top of the fuel pump. I thought it was just bad gasket and after cleaning a bit on the top of the pump I noticed the cracks on the plastic (hair lines) around the inside edge on top of the fuel pump. I dried it with paper towel and shook the car a bit I can see fuel keep zipping around. I just ordered new pump from local Audi dealer and their online price is great. After tax, gasket and new pump ring I am out $313. Let's hope they have them in stock so I can replace the bad pump tomorrow. I have been planning on replacing the fuel filter and I guest it is being done now. Hope the pictures shows the cracked on the plastic and this helps others.