1.9 TDI (PD) High fuel consumption :(

[heaton]

Hi,

 

Just bought a Skoda Roomster 1.9tdi. The fuel consumption is very high. I drive like Miss Daisy and still the consumption is 6,5/litres per 100km (about 36mpg).

 

The service was made by the dealership and the airfilter was changed. 

 

What could it be? I used vag com to read codes and there is no codes. Also when i disconnect MAF the car is very weak... that means the MAF works? 

I have some values from VCDS, hope someone can look them over and see if there's something wrong. 

 

Thank you.

 

 

 

 

 

[Phil-E]

I would start simple.

 

Check all tyres are correct pressures and no signs of wear, check all wheels are moving freely (sticking brakes).

 

Any smoke out of the exhaust? Does it rev freely and feel strong when accelerating?

 

Phil

[heaton]

I would start simple.

 

Check all tyres are correct pressures and no signs of wear, check all wheels are moving freely (sticking brakes).

 

Any smoke out of the exhaust? Does it rev freely and feel strong when accelerating?

 

Phil

 

The tyres are correct pressure, and also looks fine ( no signs of wear). They also move freely. No smoke or strange smell from exhaust. Feels a bit "slow" when accelerating, i dont hear the standard "wistle sound" from turbo so much compared to my Octavia 2.0tdi. But its maybe because its a different engine. :(

Thanks,

Heaton

Edited 10 November, 2015 by heaton

[bigjohn]

The tyres are correct pressure, and also looks fine ( no signs of wear). They also move freely. No smoke or strange smell from exhaust. Feels a bit "slow" when accelerating, i dont hear the standard "wistle sound" from turbo so much compared to my Octavia 2.0tdi. But its maybe because its a different engine. :(

Thanks,

Heaton

 

6.5 l/100km is about 43.45 mpg (Imperial not US)  - calculation sum is 282.481/6.5 - so it's less than I'd expect for this engine in a smaller car (282.481 is a constant) although it's reasonable if just driven around town

 

Never  really heard the turbo my previous Superb 1.9pd 100 (same engine I think) but it pulled really well from low revs and always did 50mpg (big car!) 

 

I once had a problem with the vacuum system that operates egr, variable vane and anti shudder turn off - this really affected performance and eventually (after some weeks) it did put an engine management light on that reported and egr problem. It was a small bore hard plastic pipe that had worn through because of diesel vibration but the small flex hoses can fail - all are common faults. When fixed I thought wow - this thing goes well!

 

Another symptom for this after a while was a shudder on turn off as there was no vacuum to operate anti-shudder valve

 

Not sure where all of this is on a Roomster but follow vacuum pipes from the brake servo pipe where there is a T off from large pipe to small. On UK cars they usually cross over to the other side of the engine bay first but probably not in Sweden! 

 

Alternative potential issue 1) stuck turbo variable vanes - doesn't always throw a code

 

Alternative potential issue 2) Is it running of four cylinders? A known issue is the failure of the injector wiring loom that sits in hot oil

 

Alternative potential issue 3) Any noise from the camshaft - Cam lobes that operate pd pumps can wear especially if the wrong oil has been used in the past

 

Alternative potential issue 4) Diesel filter

 

 

 

Rather than driving like the pope - give it some beans too loosen things up - especially the turbo vanes

Edited 10 November, 2015 by bigjohn

[eccleshill]

Are you getting the fuel consumption from the trip computer?  Could be that it is inaccurate.  Fill the tank, drive a few hundred km and fill up again.  The amount of fuel for the 2nd fill is the amount you used for the few hundred km.  Calculate your consumption from that.

 

As someone else said 6.5km/100km is 43.5mpg (Imperial).  If you are doing short trips around town with a cold engine then that would be the low side of normal.  My old 1.9TDi Octavia would drop into the mid 40's around town from cold.

 

I have also found that driving turbo diesels like Miss Daisy is not good.  Drive it like you rented it for 5-10 miles at least once a week and give it full throttle acceleration a couple of times each journey once the engine is warm.  You will be repaid with a broad smile and improved long term fuel consumption.  Could be that the previous owner drove like a granny and the whole thing is bunged up.  Give it a good long thrash on the motorway - it will work wonders.

[Phil-E]

Well spotted on the MPG conversion.

 

So yeah 43mpg isn't uncommon on a cold engine on short trips or even spirited driving.

 

If we do just town trips our average MPG drops to around 40-44mpg. Throw in some longer journeys as well and we're averaging 49mpg. Then doing just long journeys we're over 50mpg.

 

This is on a Octavia with DSG gearbox a trip from York to Dover 302 miles driven with 455 remaining. Calibrated trip computer (it actually under-reads now by a very small amount - 0.5mpg by my last calcs). So yours should be able to get better. In the end we made it to Germany on one tank having driven 677 miles (1090 kms).

 

 

[philip2041675]

Hi Heaton

 

Just a thought when I read of your fuel consumption.  I had experience of a 1.9TDi engine in a VW which developed something uncannily similar- an unperky engine and high fuel consumption. It turned out to be the air mass meter or air flow meter. This sits in the engine after the air filter. It is very sensitive to particulates and can often fail if airfilter hasn't been changed as frequently as recommended. As you probably know the air mass meter very accurately mixes fuel and air to send into the engine- the consequence any amount of fuel gets burnt. It is fairly simple to remove.

 

With regards

 

Philip

[bigjohn]

Hi Heaton

 

Just a thought when I read of your fuel consumption.  I had experience of a 1.9TDi engine in a VW which developed something uncannily similar- an unperky engine and high fuel consumption. It turned out to be the air mass meter or air flow meter. This sits in the engine after the air filter. It is very sensitive to particulates and can often fail if airfilter hasn't been changed as frequently as recommended. As you probably know the air mass meter very accurately mixes fuel and air to send into the engine- the consequence any amount of fuel gets burnt. It is fairly simple to remove.

 

With regards

 

Philip

 

Mass Air Flow meter "usually" throws a code but plays havoc if broken as everything gets confused re air in & exhaust out including via EGR so engine management plays safe

 

If no codes showing at all (EGR, MAF usually throw one) the car simply may have been driven toooooo gently in the past and needs persuading back into life. If the turbo is partially gummed up a bit of italian tuning may save it (if totally gummed up it won't but it would also throw a code). 

 

The 1.9 pd should feel lively in this car especially from 1600rpm to 4000rpm

 

Few follow up questions:-

1) Does it smoke on full throttle?

2) If you floor throttle in lowish gear on clear road what rpm does it start really pulling

3) Does it shudder when turning the engine off?

Edited 12 November, 2015 by bigjohn

[KeithCheetham]

Has it ever had a cam-belt change, the reason for asking is that the torsion value, box 4 in group 4 which is showing -3.6 doesn't look correct (possibly retarded timing) based on the details contained in the following:-

http://www.myturbodiesel.com/wiki/camshaft-timing-torsion-value-adjustment-on-vw-and-audi-pd-tdi-engines/

This is mine pre and post setting.

Address 01: Engine (045 906 019 BR)

13:15:15 Group 004

903 /min RPM

2.2 °BTDC Ign. Timing

6.1°KW Idle Stabilization

3.9°KW Idle Stabilization

Address 01: Engine (045 906 019 BR)

13:21:04 Group 004

903 /min RPM

2.2 °BTDC Ign. Timing

6.1°KW Idle Stabilization

0.0°KW Idle Stabilization

Edited 13 November, 2015 by KeithCheetham

[bobspark]

When I first had my second-hand Scout 1.9,at 2.5 years old, it would do minimum 53mpg .Then I gave it its first major service at 4 years old which included a new air filter. The fuel consumption went down hill. Putting another air filter in did not improve things. Illness got in the way untill early last year I decided it must be the mass air flow meter, and mpg was poor at 46mpg.I thought maybe I may have disturbed a fine layer of dust when I lifted the air filter cover up? Even with a 60 bit set of adapters I couldn,t find one to fit the MAF star shaped screws, so took the complete tube out and gave it a blast of compressed air from a can I bought at a jumble sale.Mpg improved.

Mpg started to drop again recently ,so I removed the MAF screws using electrical pliers as a pair of grips on the sides of the screw heads. Gave the MAF a good clean with electrical contact cleaner which I bought at Halfords for about £4.

I then replaced the 2 screws with pozidrive self tappers I happened to have in the garage.

As I only fill up every 2 months its going to be a while till I find out if has improved things. 

 

The above I mentioned in another thread,and things did improve back to 53mpg,athough I had to give it another clean when mpg dropped again.