Anything I have missed?

dirtdi

Member
Joined
Jun 6, 2006
Location
UK
TDI
pd 130, di 90
I am trying to improve the economy of my '01 PD 130hp Passat. I was getting mid 40's (imp.) which I don't consider adequate (I am used to mid 50's from non-PD 110hp). So far I have done the following:

New air filter
Pumped up the tyres (42F 36R)
Cleaned the intake
Blanked the EGR pipe
Blanked the vacuum line to the anti-shudder valve
Re-seated the MAF connector with electrical grease

I have noticed an improvement of about 5% from that lot. I am going to change the fuel filter (I don't know if that would help economy?) and do an oil service. I would really appreciate any advice on what else I could do to increase economy on my PD. I am considering a re-map and a cat removal. I have always found cats hit fuel economy in the past but I don't know about this engine.

I was just going to put in a good quality 10/40 but I am interested in what sort of gains you might get from thinner oil (110000 on the engine). I am not interested in changing driving style - just making the engine more efficient.

I was thinking about MAF or Temp. sender problems but the car drives very well and doesn't show any warning lights.

Many thanks for your help.
 
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daBooj

Veteran Member
Joined
Apr 8, 2005
Location
Chapel Hill, NC
TDI
Jetta GLS, 2004, could only find silver
Find a good oil that is rated 506.01. That will be a 0w30, and is great for your engine. The 506.01 is the VW rating, and covers all diesel engines sofar. The oil should give you about a 10% boost in economy. Here, most folks use Elf as that is most readily available. If I remember right, Ernie Rogers actually saw better economy using the Motul 506.01 oil. Both should be great.
 

aham_uk

Veteran Member
Joined
May 20, 2006
Location
Newcastle UK
TDI
VW BORA 115bhp 6 speed
My PD 115 bora improved from 48mpg (imp) to 60-64, All I have done is change the MAF (by design they will fail over time) and replaced the temperature sensor. My temperature sensor went cold when driving but it also sends readings to ECU for fueling levels.
Forte diesel treatment is the only fuel addative I have acutally seen work for me.

Where are you based in the UK? If near Newcastle you can swap out MAF with mine to see if it makes the differnce.

Fuel filter should not make any difference.
I would never run tyres at 42psi as I like my life more than a few MPG.
 

dirtdi

Member
Joined
Jun 6, 2006
Location
UK
TDI
pd 130, di 90
Hi Aham,
That is an astonishing coincidence - posting on an American site and getting a reply from the same town in England. I am having VW do an oil change service (just to keep the history) and have asked them to specifically check for fault codes related to MAF and temp. sensors. I have a horrible feeling these may not show up though - can anyone advise if a fault will be obvious on vag-com? The temp. gauge has never flickered - does this mean the sensor is OK?

I think 42 psi is a touch high as well. I find it handles best at about 38 front and 32 back. 34 front is slightly better for wet grip but 38 perks up the steering response a treat. Braking distances dont seem to change at all. I think I will settle for 36/32 as the best compromise.

Thanks
 
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aham_uk

Veteran Member
Joined
May 20, 2006
Location
Newcastle UK
TDI
VW BORA 115bhp 6 speed
Could be the 15W-40 churning around the inside of that engine.
Nice to meet you tonight and hope you get the most out of the your servicing.

If you need anything you have got my phone number
Andrew
 

dirtdi

Member
Joined
Jun 6, 2006
Location
UK
TDI
pd 130, di 90
A quick update:

New MAF and temperature sender - drives better cold but less perky hot. Fuel consumption improved by maybe 1-2mpg.

New VW oil rated as longlife 0W30 - maybe another 1 or 2 mpg tops.

All in I have got it from mid 40's to very high 40's, still not where I would like it but I have run out of ideas. Any other suugestions would be appreciated.

I would like to try the fuel temp sender resitor next (thanks for the offer aham - I will be in touch shortly).
 

aham_uk

Veteran Member
Joined
May 20, 2006
Location
Newcastle UK
TDI
VW BORA 115bhp 6 speed
Timing could be way too advanced, when cold it retards it's self and when it's hot it could advance not allowing the engine to get all the energy from the fuel.

Everything else has been done.
 
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