1.9TDi 130 AVF mpg dropped

Jarre

Registered User
Hi,

since getting my '04 B6 Avant 1.9TDi 130 AVF i've tracked the real world mpg (not trip) and have been averaging between 40 and 42mpg. The last two tanks have been 37.8 and 37.3, thats quite a drop compared to any other tank (tracked over 4000 miles in total), so i'd like to try and find out whats caused this.

The car was remapped for the most recent tank, however the mpg dropped before the remap, so that cannot be to blame.

The fuel filter was replaced around 4000 miles ago, air filter was checked and was fine as it had had a service only 3000 miles before that.

Power doesn't seem to have dropped, even when standard i used a mobile phone dyno app and it quoted about 132bhp (very very very rough guide i know) but it doesn't feel down on power, and after the remap it does feel sprightly.

So I would appear to have dropped around 5mpg but without any power loss. My initial thinking was MAF but then whenever i've read about that people seem to have power losses too. The only other thing i can think of at the minute is the air conditioning being under a lot more load with the warmer weather more recently, but i don't think this would cause such a significant drop.

Any help is appreciated - i have my own genuine VCDS to use.

Thanks!
 

pauldazzle

Registered User
Check the temp the ECU is getting from the coolant temp sensor in VCDS. My mpg definitely drops a bit when the AC is on for sure.
 

Jarre

Registered User
I have replaced both the coolant temp sensor and thermostat since getting the car. VCDS displayed a coolant temp of around 91 degrees c when I was out earlier.
 

pauldazzle

Registered User
CTS isn't the problem then.
 

Ovid

Registered User
Are you filling up at same place as supermarket fuel always gives less mpg due to poor fuel grade and copious amounts of nasty additives which are cheap hence the reason they can sell it cheaper, i used to drive a fuel tanker and would not touch SM fuel with the proverbial pole!
 

Jarre

Registered User
The 37.8mpg tank was tesco no with a millers one shot treatment and the 37.3 tank was after remap and Jet diesel no additive
 
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