Fuel economy tanked

[sacha35]

Hi guys hope you can help.
Have an Audi A4 TDI CAGA with 135,000 miles. Over the last few weeks the fuel economy has dropped out where I'm getting no more than 20/25mpg around town, on long runs its acting as should with a return of about 54mpg.
The car starts perfect and has no misfires at all, but does seem to be getting hotter more quickly than it used to and down a bit on power. But it's not over heating and theres no water or oil loss. There is no smoke from the exhaust its absolutely clean as, but even the shortest run I can see the fuel gauge drop.
I have hooked up VCDS and run some tests, apart from the DPF pressure being up slightly and the normed load value,, but what does stand out is the Fuel consumption 0.72 l/h. I cannot see anything untoward. Hoping you can have a look over the results and give you insight as to what's going on or any further tests I should carry out.
Many Thanks

Address 01: Engine (03L 906 022 B)
09:10:28
IDE00025 Coolant temperature 84 °C
IDE00085 Normed load value 21.6 %
IDE00351 Main injection: start of activation -4.00 °
IDE00352 Main injection: duration of activation 540.8 µs
IDE00365 Injection quantity deviation cylinder 1 0.16 mg/stroke
IDE00366 Injection quantity deviation cylinder 2 -0.04 mg/stroke
IDE00367 Injection quantity deviation cylinder 3 0.22 mg/stroke
IDE00368 Injection quantity deviation cylinder 4 -0.34 mg/stroke
ENG106252 Synchronous angle 0.20 °


09:11:16
IDE00025 Coolant temperature 85 °C
IDE00085 Normed load value 21.2 %
IDE00383 Pre-injection 1: activation start 1.71 °
IDE00384 Pre-injection 1: activation duration 335.2 µs
IDE00385 Pre-injection 2: activation start 7.58 °
IDE00386 Pre-injection 2: activation duration 269.2 µs
IDE00387 Post-injection 1: activation start 0.00 °
IDE00388 Post-injection 1: activation duration 0.0 µs
IDE00389 Post-injection 2: activation start 0.00 °
IDE00390 Post-injection 2: activation duration 0.0 µs
IDE00472 Mean injection quantity 6.26 mg/stroke
ENG106252 Synchronous angle 0.15 °


09:11:44
IDE00025 Coolant temperature 84 °C
IDE00085 Normed load value 23.5 %
IDE01380 Pre-injection 3: activation start 0.00 °
IDE01381 Pre-injection 3: activation duration 0.0 µs
IDE01382 Post-injection 3: activation start 0.00 °
IDE01383 Post-injection 3: activation duration 0.0 µs
ENG106252 Synchronous angle 0.18 °


09:12:57
IDE00025 Coolant temperature 86 °C
IDE00085 Normed load value 20.0 %
IDE00427 Particle filter: difference pressure 11 hPa
IDE00433 Particle filter: oil ash volume 0.16 l
IDE00434 Particle filter: soot mass calculated 8.61 g
IDE00435 Particle filter: soot mass measured 7.54 g
ENG105211 Exhaust gas vol.flow particulate filter 60.4 m³/h
ENG106252 Synchronous angle 0.22 °


09:15:57
IDE00025 Coolant temperature 89 °C
IDE00085 Normed load value 25.1 %
IDE00201 High fuel pressure: specified value 250000 hPa
IDE00371 Fuel consumption 0.72 l/h
IDE00475 Fuel Pressure Regulator Valve 21.18 %
IDE00476 Fuel Metering Valve 35.17 %
IDE00589 Fuel pressure 23620 kPa rel
ENG105211 Exhaust gas vol.flow particulate filter 60.1 m³/h
ENG108386 Fuel high pressure: actual 236200 hPa
ENG108385 Fuel high pressure: control difference 11300 hPa
ENG106252 Synchronous angle 0.29 °

[Crasher]

Nothing jumps out at me, do a service regen when standing and see if that helps.

[sacha35]

Thanks Crasher.

[sacha35]

Thanks, Crasher. I forgot to mention that I did a forced regen when it first started. I also did a compression check on all cylinders at the weekend, and they all measured 400 psi. I took off the rocker cover, inspected the cams whileinjectorswereout, and they look like new, and couldn't see anything untoward with the followers.

The number two injector has a very slight tap, but it's nothing too concerning. However, I'm wondering if, even though the injectors are well within range, there might be something related to overfueling due to them being the original injectors that have coveredsomemileage. Can you advise?

[Crasher]

I was thinking more restricted DPF, the sensor can lie.

[sacha35]

Thanks Crasher. Will do another regen, if still the same will send away to be cleaned and tested.

[swalker]

Are forced regens not sore on the engine?
I got my Q5 (CJCA) from mid 30s to low 40s by doing the following:-
Secured the under tray with the proper fixings to stop it flapping about on cable ties, made a difference of 2 MPG!
Replaced the 285 tryes with what was on the sticker 255, and made sure the profile corrected the gearing as the wheels are 21s not 20s.
Carbon clean - marmite I know, but has worked for me, with 135K I think you will see a difference.
Ran a batch of fuel treatment (archoil DMax)
Service

It does sound like something more is going on with the overheating, hopefully you get sorted easy enough.

[Crasher]

Not a forced regen whilst driving, a service regen whilst standing

[mickeybo]

A faulty maf signal will cause the computer to give too much
or too little fuel

disconnet maf sensor and drive your vehicle for a few days with maf disconnected