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Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: tungmeister on 13 August 2011, 11:20

Title: tdi 150 bad mpg?
Post by: tungmeister on 13 August 2011, 11:20

Hi guys, Picked up a gttdi 150 a couple of weeks ago, thrilled with it other than the MPG. Driving ridiculously conservatively as in constantly keeping the revs below 1500 and basically not accelerating atall i can see into the 40's but if I actually drive the car up to like 2000-2500 I'm struggling to see more than 35 MPG, on shorter runs and if I actually drive briskly it's sometimes as low as 25-30. Does this seem normal or does anyone think I've got an issue? I've had vcds on it and checked for boost leaks and everything looks ok if you do think there's an issue could you point out measuring blocks to look at etc.

Edit: I've already had my EGR valve off and given it a good clean.

Dan

Title: Re: tdi 150 bad mpg?
Post by: yourloveismydrug on 13 August 2011, 12:53

how are you working it out ?  are you taking the readings from the computer or working it out from fuel in and mileage done .

Title: Re: tdi 150 bad mpg?
Post by: yourloveismydrug on 13 August 2011, 12:53

Do Maf faults show on the vcds software

Title: Re: tdi 150 bad mpg?
Post by: Steve_PD on 13 August 2011, 13:00

sometimes, not all the time.
You can do data logging which will give you an idea of how its working.

Maf or split boost pipes

Title: Re: tdi 150 bad mpg?
Post by: tungmeister on 13 August 2011, 13:33

I'm leaning towards maf at the moment, I'm going on what the MFA is showing. If i'd got a boost leak wouldn't it have shown up from logging in vcds?

Title: Re: tdi 150 bad mpg?
Post by: RTechUK on 13 August 2011, 14:17

Could be sticky turbo vnt, lower boost pipes leaking or maf.

Title: Re: tdi 150 bad mpg?
Post by: tungmeister on 13 August 2011, 15:09

wouldn't a sticky vnt also show up from boost logging as over boost?

Title: Re: tdi 150 bad mpg?
Post by: Kerrse on 16 August 2011, 10:19

I've never had good mileage in my pd 150 in 5 years of owning it never got more than 450miles to a tank   :cry: i cant work out how people get 600miles to a tank   :undecided:

Title: Re: tdi 150 bad mpg?
Post by: RTechUK on 16 August 2011, 11:25

Quote from: tungmeister on 13 August 2011, 15:09

wouldn't a sticky vnt also show up from boost logging as over boost?

Not always, depends on ecu software and how long the ecu see the time of over boost at x amount

Title: Re: tdi 150 bad mpg?
Post by: tungmeister on 16 August 2011, 11:41

I think I'll do some more logging today and post up some graphs to see what people think.

Title: Re: tdi 150 bad mpg?
Post by: RTechUK on 16 August 2011, 12:30

Quote from: tungmeister on 16 August 2011, 11:41

I think I'll do some more logging today and post up some graphs to see what people think.

:smiley:

Title: Re: tdi 150 bad mpg?
Post by: scarr89 on 29 August 2011, 18:17

I think I maybe having a similar sort of thing - ever since I took an ebay 'chip' out of my car. Does this mean that I will have to take it to a garage and get them to do some tests? I am competent with tools but do not have (or even know) what data logging is. How tough is it to clean the EGR?

Title: Re: tdi 150 bad mpg?
Post by: bricey on 29 August 2011, 18:20

try owning my car.... :undecided:

Title: Re: tdi 150 bad mpg?
Post by: scarr89 on 29 August 2011, 18:53

http://www.golfgtiforum.co.uk/index.php?topic=94783.0

Would this topic also apply to a diesel engine? I have been getting a little bit of a rough idle, it suddenly leaping up from 800 to like 1100-1200 for a while then dropping back down. My car has 110k on it and I don't know if it has had the MAF replaced? How long would they normally last?

Title: Re: tdi 150 bad mpg?
Post by: scarr89 on 30 August 2011, 12:50

Any one  :smiley:

Title: Re: tdi 150 bad mpg?
Post by: tungmeister on 30 August 2011, 18:45

Does your temp gauge ever fluctuate at all? a faulty temp sender can cause the random rev fluctuation symptoms.

Title: Re: tdi 150 bad mpg?
Post by: scarr89 on 30 August 2011, 18:54

Temp is fine, never gone above the middle value (90 I think) just unplugged my MAF and took it for a spin and it was flippin dire, so it cannot be that can it? After plugging it back in I then noticed a bit of hesitation before the turbo kicked in, and then it seemed to almost continue making wooshing noises after I took my foot off the gas. Do you know what this could mean? I Then checked most of the pipes easily visible for loose connections splits and didn't find anything major...