Sudden fuel consumption increase on 8P 2.0 TFSI

[Nanz]

Hi all

I have an Audi 2006 TFSI 2.0 which I have owned for about 6 years or so. I haven't had any mechanical issues with the car, its in amazing condition considering how old it is.

This year however, I had the brakes (front and back) and shocks replaced, as well as the AC Compressor.

Since that work has been done, I have noticed that my car is drinking through the fuel. A tank of gas (55l) is getting me only about 150 - 170 miles when previously it was getting me at least 280+. The car is regularly serviced as well. The car has only done approx 50,000 miles as well.

There are no service lights on and no odd noises, I have even tried driving without the AC and its still going through the fuel at a ridiculous rate.

We only use the car for dropping off the kids to school and the odd errand here and there so there is no consistent motorway driving.

Has anyone experienced anything like this before? Any idea what it could be?

 

[nluk100]

More than likely a split dv - have you had it checked at all? It could also be a failed pcv but less likely to cause such a large increase in fuel consumption, just usually a lumpy tickover.

 

[Nanz]

I am sending it back to the garage next week to get them to check their work.

Is it possible that the AC compressor replacement caused the split DV? I don't think its the pcv as the tickover seems fine.

 

[SootySport]

Brakes sticking? Although you notice this by the car being sluggish or pads squeaking.

 

[Nanz]

Brakes sticking? Although you notice this by the car being sluggish or pads squeaking.

No I have checked that, they seem to be perfectly fine.

 

[prt57]

Does the temp gauge sit at 90 degrees or is it lower? If lower then the thermostat needs replacing as this can affect fuel consumption.

 

[Nanz]

Does the temp gauge sit at 90 degrees or is it lower? If lower then the thermostat needs replacing as this can affect fuel consumption.

Hmmm, as far as I can recall it sits fairly standard at around 90, but ill check that again tomorrow.

 

[Nanz]

Just an update, took it back to the garage and they ran diagnostics on the car. It came up with a Fault Code: 12600 (P3138) which is: intake manifold runner control regulation deviation.

The garage has cleared the code now and told me to see how it goes for a week. I've read a few things across forums that it could be the PCV.

There are no engine lights, no smoke, drives perfectly well, so just have to see how it goes. I really don't want to have to change the manifold.

 

[Sayam]

Just an update, took it back to the garage and they ran diagnostics on the car. It came up with a Fault Code: 12600 (P3138) which is: intake manifold runner control regulation deviation.

The garage has cleared the code now and told me to see how it goes for a week. I've read a few things across forums that it could be the PCV.

There are no engine lights, no smoke, drives perfectly well, so just have to see how it goes. I really don't want to have to change the manifold.

I was going to say the really cold weather (I'm in Yorkshire) has made a noticeable difference to the fuel economy of my car, but clearly based on the above there's more at play here.

 

[Nanz]

Just as an update, I changed the PCV this afternoon, fairly simple job. When I took the current one off, it was full of a yellow type gunk. Not quite sure what it is. I've attached a pic of it here, its a bit blurry cos its in a bag but you should get the idea.

Lets see if this improves the fuel consumption.

 

[Nanz]

Thought I would update this as the PCV update improved things, but I was still only managing 200 - 220 miles on a full tank.

I went and saw @DJAlix last week and he did a scan on the car and saw that the Intake Manifold Runner wasn't calibrated properly (P3137).

He calibrated it and since then, I have noticed a vast improvement in the MPG. I will report back again once I fill the tank and see what I can get out of it, but currently with city driving I'm getting about 23mpg, previously I was getting about 16mpg.

 

[Nanz]

Thought i'd update again here. It's been slow going trying to get this sorted for various reasons.

Since the last post I've done the following:

• Full Service
• Coolant Sensor
• Thermostat (Audi original)
• DV (rev G - Audi original)

For some reason, I didn't notice it earlier but the coolant temp in my car has been going up and down massively, from 90 to 60 when driving or the air con was on. It would never stick at 90.

Having had the thermostat changed today, I've noticed its staying at 93 consistently now, so I am hoping this helps the car run better and not so lean.

I'll report back once I drive it a bit and see how the MPG is tracking.

 

[Nanz]

So I think I might have finally solved the issue. I cleaned the MAF sensor today and took it for a test drive (from cold). I am now getting 25+ MGP driving local and went up the A1 and managed to get it up to around 34+ MPG.

Going to see how this behaves over the next couple of weeks, hopefully with the school runs it shows the same numbers.

I might buy a new MAF sensor to replace this one as I could see a bit of rust on it when i was cleaning it.