REALLY bad gas mileage... What do you get for mileage?
04-15-2011, 09:04 AM
#21
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Not sure if a traditional $50 OBD scan tool will pick up the soft codes or not. I have the EBAY autonostics OBD cable and I use Ross-Tech's free software. (Ross Tech makes vag-com) This functions enough to pull codes and clear codes on most of the modules in the car. I think the cable is like $20-30 dollars. Just bought and am waiting for the real deal Ross-Tech cable. I went in on a group buy over at audizine. What part of MA are you in? I'm in West Springfield.
04-15-2011, 10:40 AM
#22
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Not sure if a traditional $50 OBD scan tool will pick up the soft codes or not. I have the EBAY autonostics OBD cable and I use Ross-Tech's free software. (Ross Tech makes vag-com) This functions enough to pull codes and clear codes on most of the modules in the car. I think the cable is like $20-30 dollars. Just bought and am waiting for the real deal Ross-Tech cable. I went in on a group buy over at audizine. What part of MA are you in? I'm in West Springfield.
04-15-2011, 11:04 AM
#23
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Even though I had to put it on the CC the Ross Tech cable is like the one MUST HAVE "tool" for VW/AUDI people. You can do so much with it. Frankly had I bought mine a while ago it would have paid for itself already because I've replaced other parts which I thought were bad and they turned out to be fine. Vag-Com allows you to datalog sensors so you can see what's acting up and when. (I.E. EGTS's, Mass Air Flow sensor, fuel trims, O2 sensors etc.)
EGT sensors are expensive and on the S4 / Allroad, the driversside EGT sensor is a GIGANTIC PITA to replace. I've been wrenching for 15 years and I got extremely frustrated when I did mine. The cheapest place I found that sells new sensors is here:
http://www.ecstuning.com/Audi-B5_S4-...sor/ES2063767/
You should replace them in pairs but if you were really strapped for cash and knew you had a bad one you could replace just one. There are some places that sell them individually and still others that sell them rebuilt. They can't be cleaned because getting "dirty" isn't usually what causes them to fail. They just have a simple metal probe that sticks down in the exhaust flow. The "body" of the EGTS is a smart device, it has a full circuit board inside that takes the variable resistance reading from the exhaust probe and converts it into a Pulse Width Modulation signal (PWM) which is then fed to the ECU.
PWM is just a square wave signal and the length of the "square" or "tooth" increases or decreases based on the temperature of the sensor/exhaust. The ECU measures the period of the square wave and through some table/algorithim equates that to exhaust temperature. You don't technically have to use VAG-COM to monitor this signal, you could hook up a oscilloscope and watch the square wave for inconsistencies etc. You can get a 2 channel USB/PC based oscilloscope device for $100-150. Frankly at that point though I'd just put that money toward the Vag-Com.
My code was "SHORT TO PLUS" which I took to mean the signal was stuck HIGH.
You can have those sensors coded out of the system by a shop, however they are actually there for a reason, to help keep exhaust temps down. If exhaust temps get too hot the turbo's can be damaged.....
EGT sensors are expensive and on the S4 / Allroad, the driversside EGT sensor is a GIGANTIC PITA to replace. I've been wrenching for 15 years and I got extremely frustrated when I did mine. The cheapest place I found that sells new sensors is here:
http://www.ecstuning.com/Audi-B5_S4-...sor/ES2063767/
You should replace them in pairs but if you were really strapped for cash and knew you had a bad one you could replace just one. There are some places that sell them individually and still others that sell them rebuilt. They can't be cleaned because getting "dirty" isn't usually what causes them to fail. They just have a simple metal probe that sticks down in the exhaust flow. The "body" of the EGTS is a smart device, it has a full circuit board inside that takes the variable resistance reading from the exhaust probe and converts it into a Pulse Width Modulation signal (PWM) which is then fed to the ECU.
PWM is just a square wave signal and the length of the "square" or "tooth" increases or decreases based on the temperature of the sensor/exhaust. The ECU measures the period of the square wave and through some table/algorithim equates that to exhaust temperature. You don't technically have to use VAG-COM to monitor this signal, you could hook up a oscilloscope and watch the square wave for inconsistencies etc. You can get a 2 channel USB/PC based oscilloscope device for $100-150. Frankly at that point though I'd just put that money toward the Vag-Com.
My code was "SHORT TO PLUS" which I took to mean the signal was stuck HIGH.
You can have those sensors coded out of the system by a shop, however they are actually there for a reason, to help keep exhaust temps down. If exhaust temps get too hot the turbo's can be damaged.....
04-15-2011, 04:59 PM
#24
just went on a trip in my m3 (414 hp V8) in hilly areas, hit some stop and go traffic. about 60 miles there and back. drove about 75. got 24.5 mpg. not bad for a V8.
I assume the 4,2 allroad gets less thant the 2.7 ?
I assume the 4,2 allroad gets less thant the 2.7 ?
Last edited by sayemthree; 04-15-2011 at 05:05 PM.
04-15-2011, 05:19 PM
#25
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Slightly, but not by much. The rated numbers only differ by 1 mpg, but it seems as though in real world use the 4.2 is worse. I have never got better than 20mpg highway with mine, and generally average 14 in city driving. I usually calculate my mileage at each fill-up, and my record best was 20 mpg and my record low was 12 mpg for a tank of gas.
04-16-2011, 03:52 PM
#26
Just got back from a 280 mile round trip with my '03 2.7t Tip AR. Averaged 21.3 mpg running 74 mph and 98% highway. Suspension was level 1, premium fuel, and 32 psi in tires. Not great mileage, but not awful either. Think it would have been higher, but on my way home I ran into a pretty stiff headwind from a approaching storm. Maybe would have got 22 mpg average if not for that.
04-18-2011, 08:28 PM
#27
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Part of the problem with Allroad MPG is due to its gearing. I don't know of a single other car that spins engine in 6th gear at 3.5k rpms while driving 80mph... which is why it eats so much fuel. Almost like there was a code in its computer which says "If rpm> 3000 then punish driver".
It'd be interesting to see if it would really help. From what I understand, a couple people have done it on the 4.2, but it didn't make much difference. I think the 2.7 would benefit, maybe put it at a better place on the BSFC map for highway cruising.
04-19-2011, 06:09 AM
#28
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Swap in a taller 6th gear.
It'd be interesting to see if it would really help. From what I understand, a couple people have done it on the 4.2, but it didn't make much difference. I think the 2.7 would benefit, maybe put it at a better place on the BSFC map for highway cruising.
It'd be interesting to see if it would really help. From what I understand, a couple people have done it on the 4.2, but it didn't make much difference. I think the 2.7 would benefit, maybe put it at a better place on the BSFC map for highway cruising.
04-19-2011, 06:36 AM
#29
I average about 300 miles/tank, that's about 90% hwy/10% city. Stock levels/TIP.
PS: 2.7T
PS: 2.7T
