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Discussion Starter #1
mk3 tdi golf 1997 ahu. i seem to be getting very poor fuel economy from my golf, last calculation of 35ish mpg (petrol car figures). recent all filters service, recent headgasket and timing belt (checked and timed proffesionally) no black smoke on acceleration and does not get raced or thrashed all the time, (in comparison my old audi 80 1993 1z tdi i used to get 55ish mpg with the same driving style) any suggestions as to why this is so poor would be greatly recieved. this car is my first golf so im learning all the time, many thanks
 

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This is a tough one - check parking brake or the brakes - it could be sticking - lift each wheel and it should move easily and there should just be very light resistance at the wheel. Check for proper engine timing. Look through the FAQ, 1000Q: mk3 section and you'll find the timing belt writeup. Use this to check the engine timing. Poor timing can equal poor economy. Also check the fuel injection quantity. If this is incorrect it can also result in poor fuel economy.

Direct links here:
http://www.myturbodiesel.com/1000q_how_to/multi/IQadjusthammermod.htm

http://myturbodiesel.com/1000q_how_to/a3b4/TDI_timingbelt_remove_mk3.htm

Let us know if it makes a difference or if a sensor is off! Also check the engine temp sensor. Use VCDS to see what the value the engine sees. It's not common in mk3 but low engine temp can mess with timing.
 

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Check the compression, if the engine is worn out it won't make ggood power or mileage. No black smoke doesn't sound like low compression but maybe the nozzles are worn out? Any code?
 

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Discussion Starter #4
no brake bind found,low milage engine compressions good injectors recently re-furbed, no codes, would a faulty maf sensor cause high consumption??????
 

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Get a vag com and test the MAF sensor. Log MAF actual vs. MAF requested and it will quickly show if the MAF is bad. Make sure to do some highway runs too.
 
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