Excessive Fuel Consumption.. 2013 A6 3.0

[Saabya6]

For the past 2 months, I have noticed excessive fuel consumption, especially in the city, whether it’s aggressive or not. Can barely pull 250 miles per tank with mixed driving. Car has about 94k miles now.. as well as a very faint fuel vapor smell when driving, or immediately exiting the car after driving.

Could it be possible carbon buildup? Which doesnt seem to be a huge issue on the 3.0TFSI, leaky fuel rail or injector? I know there was a recall out, but my dealer says my car doesn’t have an open recall for that.. any suggestions? Before i get rid of it lol.. thanks


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[lv2000]

I think you would notice a leaking fuel rail I wish I could get 250 miles a tank. The slight vapor in summer is pretty common

[Burnt]

You guys don't get 250 miles on a tank? Makes me rethink jumping from a TDI to the V8TT. How many gallons you guys fill per trip?

[yeuchau]

your right foot is the issue.

[Gwillplays]

I’m averaging about 28 mpg. At fill up my range goes to 550 miles. Currently at 24,000 miles. Check your fuel maps, to see if you are going too rich. Also check that O2 sensor values are flipping from lean to rich values.

[Saabya6]

I’m averaging about 28 mpg. At fill up my range goes to 550 miles. Currently at 24,000 miles. Check your fuel maps, to see if you are going too rich. Also check that O2 sensor values are flipping from lean to rich values.

I will. When i fill my car up, it only goes to 390 or 415 depending on my previous tanks’ mpg average


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[Saabya6]

You guys don't get 250 miles on a tank? Makes me rethink jumping from a TDI to the V8TT. How many gallons you guys fill per trip?

Im talking about the 3.0SC, most v8TT owners ive seen get about 250 miles per tank.. gotta love the power lol


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[Saabya6]

So since fuel rail is out, maybe its a stuck injector? Gonna drop it off to my indy on monday


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[Frenetic]

Wasn’t there a fuel pump recall on this engine and a ton of issues with leaking fuel due to poor work? I vaguely remember reading about it here.

[Saabya6]

Wasn’t there a fuel pump recall on this engine and a ton of issues with leaking fuel due to poor work? I vaguely remember reading about it here.

When i took the car in for service, they said that recall isn’t out for my vehicle


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[Mr_Nachi]

i think it has to do more with the skinny right pedal..... i get 27-31mpg if i drive on comfort and just "D" mode and drive like a grandma.... but if i drive on Dynamic and "DS" mode with out even really getting on it... i can see that drop down to 9-12mpg.... ive gotten 430-450 miles on a tank on long hwy drips steady 75-80mph.... but i have experienced 250 miles per tank with spirited driving in the mix.

[Upstate Audi]

Is your car ECU tuned? Before my car was tuned it was very easy to get a mpg over 30. As soon as I got the Apr tune if I'm not driving aggressively I get about 24 but as soon as I start to have a little fun it can very easily drop down to 20 or even in the teens.

Also here's a question for all of you. I've been noticing that my car hasn't been calculating my mpg correctly. By the time i go to refuel my car it will give me an average mpg for my tank of about 23 miles. After filling up my tank ill divide my trip miles by the amount of gas I put in my tank and it's always 2-3 mpg lower than what my car says. i know that doesn't seem like a lot but with a 20 gallon tank that can take 60 miles off the estimated range.

[Mr_Nachi]

happy pedal probs

[Mr_Nachi]

Is your car ECU tuned? Before my car was tuned it was very easy to get a mpg over 30. As soon as I got the Apr tune if I'm not driving aggressively I get about 24 but as soon as I start to have a little fun it can very easily drop down to 20 or even in the teens.

Also here's a question for all of you. I've been noticing that my car hasn't been calculating my mpg correctly. By the time i go to refuel my car it will give me an average mpg for my tank of about 23 miles. After filling up my tank ill divide my trip miles by the amount of gas I put in my tank and it's always 2-3 mpg lower than what my car says. i know that doesn't seem like a lot but with a 20 gallon tank that can take 60 miles off the estimated range.

his ecu is tuned (i tuned it); but he was complaining about gas consumption before the tune... also if it was a faulty/clogged injector car wouldnt run right i would have seen it in the tune...

[Gwillplays]

I have tested your lead foot theory and offer to differ. On numerous sprints in dynamic and ‘S’ mode I averaged 27 mpg within a range of 65 miles. He may have lazy O2 sensors that are causing his high gas consumption. If ECU is seeing lean it will make corrections by feeding injectors rich. O2 sensors play major role in this operation. It does not necessarily throw a code, but system doing its job to keep engine within safe operating parameters.

[s4nicetry]

I have tested your lead foot theory and offer to differ. On numerous sprints in dynamic and ‘S’ mode I averaged 27 mpg within a range of 65 miles. He may have lazy O2 sensors that are causing his high gas consumption. If ECU is seeing lean it will make corrections by feeding injectors rich. O2 sensors play major role in this operation. It does not necessarily throw a code, but system doing its job to keep engine within safe operating parameters.

Are you looking at short term or long term mileage? There is no way you're averaging 27mpg if you're in Sport mode and "sprinting" around.

[Mscarn2014]

3.0t with EPL stage 2 and intake. I average ~ 19 total with decently aggressive driving, city and hwy. Cruising at 80mph, I get ~30-32, about 350 on an ok tank, 450 if I do all highway.

[Gwillplays]

All highway

[Saabya6]

Hmm so should I log my 02 sensors?


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[Gwillplays]

Yes and also view your long term and short term fuel logs for excessive rich conditions. If O2s are lazy replace those first and then monitor short term fuel logs again after a week to see if conditions improved. A more intrusive test would be to test all injectors to make sure they have acceptable spray patterns and are not leaking from seats.

[Burnt]

On a TDI, I average 24 mpg / 450 miles per tank, aggressively driving, mixed highway and street driving. 27-28 If I casually drive to get some food. Haven't driven like a grandma yet.

[Kevin1]

On a TDI, I average 24 mpg / 450 miles per tank, aggressively driving, mixed highway and street driving. 27-28 If I casually drive to get some food. Haven't driven like a grandma yet.

I once did 813 miles on a single tank in my TDI. It was all highway and all done in one day. With mixed driving I average 29 mpg and about 525 miles per tank.

[Burnt]

I once did 813 miles on a single tank in my TDI. It was all highway and all done in one day. With mixed driving I average 29 mpg and about 525 miles per tank.

I used to do 27 mpg with aggressive driving until the emissions fix. Might go buy a Malone tune to revert back

[Kevin1]

I used to do 27 mpg with aggressive driving until the emissions fix. Might go buy a Malone tune to revert back

I have not done the fix. The reviews I have read have been terrible. Other than the decrease in MPG, what other observations do you have regarding the fix? Thanks

[Burnt]

I have not done the fix. The reviews I have read have been terrible. Other than the decrease in MPG, what other observations do you have regarding the fix? Thanks

Sorry to OP, highjacking threads :P
There is a lurching with the vehicle when you start and stop. Every time you cold start the car, it'll have to warm up. It sounds like your in dynamic mode till your coolant hits 140-150F. Other than that, lower MPG and more regens.

Probably worth just fixing it, taking the money and stage 2 Malone tune it back with extra power.

[Saabya6]

No harm no foul. Highway mileage is great, city for some reason just tanks into the low teens with passive driving


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[Kevin1]

Sorry to OP, highjacking threads :P
There is a lurching with the vehicle when you start and stop. Every time you cold start the car, it'll have to warm up. It sounds like your in dynamic mode till your coolant hits 140-150F. Other than that, lower MPG and more regens.

Probably worth just fixing it, taking the money and stage 2 Malone tune it back with extra power.

Thanks. My apologies to the OP as well.

[Mr_Nachi]

same here city driving in these cars suck lol... but hwy its incredible i average 32mpg on my trips to ny 130 miles each way

[GandalfTheIbis]

I have excessive fuel consumption in my 3.0T S4 as well. It hasn’t always been this way, but it has been this way since before I was tuned. I average maybe 18mpg with probably 50/50 driving but for a lot of my highway driving I’m bombing tbh. Only recently have I bothered to try to get my foot out of it.

Not long ago, I threw a code for excessive pressure from my LPFP. I’m yet to properly log my fuel trims while trying to recreate the situation. It’s on my to do list.

When I first started logging I did notice that my car was running richer than requested. I’m yet to resolve this. It’s really the last problem that I’m seeing with my car and I feel the richness might be robbing me of power on my dual pulley tune.


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[Saabya6]

I have excessive fuel consumption in my 3.0T S4 as well. It hasn’t always been this way, but it has been this way since before I was tuned. I average maybe 18mpg with probably 50/50 driving but for a lot of my highway driving I’m bombing tbh. Only recently have I bothered to try to get my foot out of it.

Not long ago, I threw a code for excessive pressure from my LPFP. I’m yet to properly log my fuel trims while trying to recreate the situation. It’s on my to do list.

When I first started logging I did notice that my car was running richer than requested. I’m yet to resolve this. It’s really the last problem that I’m seeing with my car and I feel the richness might be robbing me of power on my dual pulley tune.


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I got some spare funds, im thinking of getting two pre-cat 02 sensors just for the hell of it..


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[GandalfTheIbis]

If you’re go by to do that please do make sure you do the logging recommended by Gwill. You need quantitative analysis of change to know if it works.

My O2 sensors were both replaced for a different reason and it hasn’t made any difference. I’m still running rich.

If I wasn’t over budget on modifying this car I’d jump to APR’s test pipe file to see if it solved my problem.


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[Saabya6]

Really? Wow, good to know brother.. thank you.


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[GandalfTheIbis]

I burnt up a set of high flow cats in under 1,000 miles and I think running rich might have played a role. This is all just a guess... but excess fuel dumping into my exhaust, a little ignition and boom in my exhaust and the cats got melted and exited stage left... bending over my probably red hot O2 sensor.

If I’m right about what happened running rich without a resolution could cause expensive repairs to your car.

[ohhhmy]

Keep in mind, our cars are rated 22mpg for city. I think if you live in a bigger city where there is a lot more stop and go, you're not going to get anywhere near this. I think they got 22mpg on your average/smaller city with less traffic and stop and go. Also, if there are hills where you live, that will eat up your gas too. The engine is moving a 3500 lbs car, coasting vs braking for stop lights can make a difference too!

[Saabya6]

Keep in mind, our cars are rated 22mpg for city. I think if you live in a bigger city where there is a lot more stop and go, you're not going to get anywhere near this. I think they got 22mpg on your average/smaller city with less traffic and stop and go. Also, if there are hills where you live, that will eat up your gas too. The engine is moving a 3500 lbs car, coasting vs braking for stop lights can make a difference too!

3500 i wish! And yeah philly traffic can cut any readings in half..’i wish they all city testing in nyc or LA plus a smaller city, and combine the averages. But 250 miles out of barely a full tank sucks


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[jibo1971]

Hello have you fixed it?

[15 Phantom S6]

I've had a running rich issue on another platform, maybe this can help..

If there is a vacuum leak somewhere allowing fresh un-metered air into the stream, the primary O2 sensor will see the additional air and dump extra fuel to compensate. In my case there was nothing wrong with any parts, so replacing things didn't do anything other than bleed my wallet.

Do a full vacuum and boost leak test, it may lead you to the source of the problem...

Also, a leak around the down pipe area can let in fresh air to the O2 sensor causing a rich condition..

[jibo1971]

Mine has no problem too only sometimes it rich sometimes lean i tested millions of times about vacuum leak car goes good boost is good but dont know what to change

[Darknesssuper]

My gas mileage has gone down hill after test pipe install , and now I have an exhaust leak car get about 14mpg long term mpg . Going to install o2 spacers and fix exhaust leak see if that helps. Any els experiences this before ??