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    Thread: Bad gas mileage... why?? Audi 3.2L 6 speed

    1. 01-30-2020 02:37 PM #1
      What's up ladies and gents,

      I've run into an issue. I used to get around 20 mpg on streets and 26-28 on long highway commutes.

      Now I get 15-17 mpg on streets and 22-23 on highway. My driving habits haven't changed so why such a big drop in MPG?

      All I've done since this happened was change the the upper chain guides and spark plugs since I had the intake off.

      I checked all my vaccum lines. No leaks.

      I'm using NGK spark plugs I bought off ecs tuning. Which stated "OEM replacement". I did notice the original ones I took out had the audi logo instead of "NGK" on the side of the plug.

      Intake gasket air leak? Valve cover gasket leak? I see no oil leaks from the valve cover so I really doubt it. Anybody have any experience with an issue like this?

      Thank you.




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      Last edited by Reesescupsftw; 01-30-2020 at 02:41 PM.

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    3. Geriatric Member need_a_VR6's Avatar
      Join Date
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      15 Jetta 92 Corrado VR6
      01-30-2020 02:59 PM #2
      It is cold out and you are doing more short trips during warmup?
      -Paul
      1992 Corrado - ALL MOTOR Drag Project [email protected] and falling
      KPTuned - Official MegaSquirt: Sales - Repair - Installation - Tuning

    4. 01-30-2020 03:10 PM #3
      Yes I only work about 10 mins away from my house. So 80% of my trips are short.

      I let the car warm up about 2 mins before I drive off every morning.

      I'd usually read at least 19 by the time I get to work before I swapped the plugs and guides.

      I filled up the tank this morning so I'm going to try and get a exact MPG reading instead of trusting the cars average reading. But I do fill up more than I used to so I know im getting worse mpg. I usually fill up with mobil with the occasional Chevron.

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    6. 02-12-2020 03:32 AM #4
      So I ran the car until the fuel light came on.

      208 miles + "30 miles" left in tank= 238/ 14.5 gallons= 16.4 mpg.

      This was with about 80 miles highway and the rest street.

      Still less than the EPA rating and I shift around 2k rpm consistently unless I'm getting on the freeway.

      Last year I was getting 240 miles or so until the fuel light would go on. Something changed :/.

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    7. Junior Member
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      '06 VW Touran being R32'd, '72 VW 1200 Beetle
      02-13-2020 02:25 PM #5
      You probably want to shift a little higher - torque peak starts at about 2500 I think? I find mine pulls timing at low RPM which lowers power for the amount of fuel used. I never let mine below 2000, so shift about 2500 if I'm on the go-slow.

      I also fitted a electronic pedal controller, which I have a custom curve on, so the throttle is way less touchy down low. It made quite a difference - the car feels way less "jumpy" and more luxury like.

      I'd start monitoring your coolant temp too - either in VCDS, or on the climate panel, if the Audi one works like the MK% one, there is a secret menu. The gauge lies! It reads 90C from just 75C, and you may be staying in the slightly cool range, if the thermostat is very slightly faulty.

      Another thing you can do, that REALLY helps mine on short trips - retrofit the intelligent version of the PTC heater from a diesel MK5. This morning, I turned the heat up to MAX, but the fan speeds about 1/2 or 2/3rds. The PTC heater starts heating the car instantly, and after about 5 minutes the temp in the car gets unbearable! Because the PTC is heating the air, the engine can warm much faster. Once the engine is at 75C, the PTC heater turns off, and the coolant heater takes over, but the coolant should heat up faster - There is an obvious difference on mine.

      I only warm up until the SAI turns off - maybe 20 seconds??? Then drive off gently.

      I have a 6 mile trip to work, half country back roads. Before the PTC, I would average about 17.5 US MPG on the trip in winter (our winter is not cold though), with the PTC running for the first 3 to 5 minutes, I averaged 20 US MPG in winter and it warms up to "90C" on the gauge in about 2/3rds the distance, and the car was warmer inside! Longer trips, it becomes irrelevant.

      Switching off the heat entirely can make a huge difference.

    8. Member kgw's Avatar
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      2006 A3 S-Line 3.2 ........................................ Schricked
      02-13-2020 05:46 PM #6
      The VR6 takes a long time to come to operating temp...Somewhere around 12 miles. How often are you changing your oil? Dirty oil is definitely a bad idea in these engines! Bad idea in any engine, of course, but can lead to real difficulties with VVT/variable valve timing engines.

    9. 02-14-2020 06:52 PM #7
      I'll use VCDS to monitor the coolant then, bc I did replace the thermostat before. It gave me the CEL for that I want to say May of last year replaced it with a MAHLE thermostat. And I'll look into your PTC mod.

      And to answer the other question. I change my oil with Castrol 5w40 every 3k-5K. I just recently changed it about 500 miles ago.

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    10. Member kgw's Avatar
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      2006 A3 S-Line 3.2 ........................................ Schricked
      02-15-2020 01:23 PM #8
      Here's some useful measuring blocks for the VR6 3.2l:

      Obtained from R32OC(British forum)...

      -----------------------------------------------------

      Timing Chain Values


      Just want to post up the following top help assist in any timing chain queries. I do a lot of trawling on the German VAG forums and finally got around to translating the information below that will no doubt be helpful to many.


      The information below has been part translated in google translate and then finished/validated by my Mrs. As such it is provided here as-is.




      To test the timing chains often only the values in VCDS blocks 208 & 209 are deemed relevant. However, this is misleading for correct diagnosis of guide/chain wear and possibly other components.


      Therefore, ALWAYS reference blocks 90 & 91 when checking blocks 208 & 209. This then basically references the cam to crank timing via the intermediate shaft by correlation of the crank sensor to the cam phase sensors.




      • The timing chains values in blocks 90,91, 208 & 209 must always be read when the engine is warm. Measurements must always be taken at a minimum of about 60°C operating/oil temperature or higher, otherwise the cam adjustment is not yet fully active.


      • Measurements are always taken at idle


      Valid for both MK4 and MK5 R32:
      • Blocks 208 & 209 should be as close as possible to 0°, the spread should not exceed 3°. The absolute wear limit is 8° spread whether + or minus. If the spread is well above 3° but under the limit, then chain & guide replacement should be considered.


      Cross examination of the intermediate shaft values of blocks 90 & 91:


      Golf 4 R32 only (intake adjustment range 52°/exhaust adjustment range 22°):
      • Block 90 (exhaust) set-point is 0°, no matter the values in blocks 208 & 209, at a duty ratio of about 15.3%. The actual value should not be more than 0.5° out (Valid for both OEM & aftermarket cams). If the values are way off from 0° the timing chain may be mistimed or skipped. Around 11.25° deviation corresponds to a skip of 1 tooth.
      • Block 91 (intake) set-point is 22° between idle to about 1200RPM, no matter what the values read in blocks 208 & 209, at a duty ratio of about 15.3%.
      The actual value should not be more than 0.5° out (valid for both OEM & aftermarket cams). If the value is not close to 22° the timing chain may be mistimed or skipped. Around 11.25 ° deviation corresponds to a skip of 1 tooth.


      Golf 5 R32 & Audi BUB only (intake adjustment range 52°/exhaust adjustment range 42°):
      • For both blocks 90 & 91 the set-point value at idle is 0°, no matter what the values in blocks 208 & 209, at a duty ratio of about 15.3%.
      The actual value should not be more than 0.5 ° (Valid for both OEM & aftermarket cams).
      If the values are way off from 0° the timing chain may be mistimed or skipped. Around 11.25° deviation corresponds to a skip of 1 tooth.


      You can for whatever reason also check the cam/crank timing manually by setting the timing to TDC via the timing mark on the crank pulley then pulling the cam phase sensors and checking where the centre parts of the cam variators sit with respect to the sensor hole. I’ll dig out a pic from somewhere and annotate it as it’s quite obvious once you see it. I guess this won’t be quite as accurate as checking blocks 90,91, 208 and 209 in VCDS but might prove helpful nonetheless.


      Again the info is provided as is as I’ve only translated it and as such I’ll reference the original page once I figure out its’ address.


      Additional for consideration:


      As is known faulty cam phase sensors cause spurious readings. However a surprising point to note is that high values are not always indicative of worn guides or a stretched chain! There have been instances in Germany whereby poor service intervals (Longlife) has gummed up the cam variators/VVT assemblies/solenoids resulting in high values that’s clearly appeared to be worn chains but after several oil flushes and filter changes returned to almost perfect ‘out the factory’ values. There appears to be some correlation between the intercam timing spread and the intermediate shaft values that points to this; if I can find the original page I’ll save it off and translate it. As best as I can tell a good way to help in diagnosing if the chains truly require replacing is to also log the requested vs actual cam timing in VCDS. One of the symptoms of sluggish cam timing is mild bucking/hesitancy similar to a faulty MAF. If the actual values values are slow to match the requested values then his points to a gummed up VVT system or the inlet gauze possibly being blocked.


      The snapped chain syndrome on the early MK4s was attributed to the Sachs stamping weakening the chain links and also related to chemical corrosion caused by the extended Longlife service intervals (A topic for a future post when I get around to translating it). Chain stretch was mainly attributed to buggy/poor implementation (in early software revisions) of the VVT causing cam kickback and resonance effects on the chains at particular RPMs; this also may attribute to guide wear (but the likely main culprit was still the extended Longlife -what an oxymoron- service intervals) and (I've not fully translated this yet) possibly linked to faulty pressure relief valves in some oil pumps although that again could simply be caused by the extended Longlife service intervals.

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