AWX Poor fuel economy

[S4_dan]

Did that. With the engine warmed up it was bang on 0.0

Didn't check with the engine cold.

 

[Darran]

0.0 does not mean its right, you really should have checked value BEFORE belt chain but not to worry, just move +.5 and then see if there's a difference if its better try going to 1.0 if its worse then go -.5 etc. Trial and error now!

 

[S4_dan]

Will try at the weekend. I take it after undoing the3 bolts slightly, I turn the 18mm cam bolt clockwise slightly to get a + reading?

Cheers.

 

[desertstorm]

If you are going to start tweaking the timing it is a very small amount you have to move it. Knock it too far and it will struggle to start. small changes to the timing can help mpg a little but don't expect a lot of difference.

 

[Darran]

As Ds says move very very small amounts.

 

[S4_dan]

Ok, what a pain of a job! lol. Closest to 1.0 I can get it 1.1, even then it fluctuates about every 3 seconds to 1.7 then back to 1.1. I'll give that a whirl for tomorrow.

Checked the ECU for dtc's and I've got this;

17571/P1163/004451 - Fuel Temp Sensor (G81): Open or Short to Plus - Intermittent
Possible Symptoms

• Fuel consumption higher then normal
• Starting the engine is not as easy as normal
• Emission Levels not met

Sometimes the engine when cold catches but struggles to idle straight away, after a second or so, it's sorted.
Also, press throttle hard at idle and the revs slowly pick up until about 2200rpm then revs quicker. It's always done this and I remember it when the MOT tester was revving it for the emissions that it was doing this. Hence me thinking along the lines of the pump.....

Cheers.

 

[desertstorm]

Did you disconnect the fuel temp sensor plug or disturb it . You can see the fuel temp measurement on the measuring blocks on VCDS. normally around 10 degrees less than the engine operating temperature.

 

[S4_dan]

No. I wasn't anywhere near the fuel temp sensor. In the measuring blocks the other day it was at 68 degrees with engine at 87 degrees. Wonder if the connectors is loose? Will have a look later on.

Got to fight through this snow to work now.

 

[S4_dan]

Tried various settings with the torsion. Seems to be slightly better at 1.0. However, I'm only getting 40.6mpg still.

Is there a filter on the lift pump? How easily accessible is the lift pump to remove and clean?

I may try that first then look to have my tandem pump pressure tested. Really doing my nut in now.

Cheers.

Dan

 

[matt66604]

I would be looking down fuel side of things. Checking MVB for every possible fuel related reading and checked its plausibility. Also checking all the ancillaries... I.e alternator isn't starting to seize, AC and vac/tandem pump also.. I've seen tandem pumps start to seize and cause this issue.

 

[S4_dan]

I have given up on the old Passat. I checked everything except the fuel pump pressure.

Someone offered £550 for it and I sold her.

I then went straight out an bought a Saab 95 Estate 2.0T. Love the car. I've already remapped it to 220bhp from 150bhp.

Still have the Wifes Audi. And I have a new career change coming up in July, so once qualified and the real money starts to roll in, I'll be back in a nice Audi. But until then, this is my hack.

Dan