TDI 130 Poor MPG

[skymaster]

I drive a 2003 TDI 130 A4. I have owned is about a month or so and I was expecting better MPG than I am getting at present. I have been very light on the right foot, very gentle with it when cold and rarely rev about 3.5k on the rev counter.

It's just had full service with longlife oil, fuel filter, oil and air filter. I cant seem to get any better than 38 mpg. I took it for a 35 mile run at the weekend and expected to get better.

Any thoughts or ideas?

[andyroo]

Hi
I've got a similar Avant with Multitronic and average 36mpg the gearbox is not to blame as Audi quote very similar figures for both.
Just changed the air filter to a K&N panel replacement. This has reduced the smoke output to zero and so far looking at at the mileage used versus the mileage left (I dont have one of them computer thingys) it's looking promising for a reduction in fuel consumption I'll repost when I fill up and calculate properly brim to brim.

Andy

[vaslam1986]

I had the same problem....when i bought the car i would average around 45mpg but recently I get on average somewhere in the 30's and if i throttle it i get mid 20's maybe less. I got told it can be a couple of things firstly the your temp sensor can be on the blink. This is cheap to replace the other problem that I know of is the more dearer one...one of your injectors mayb on the blink...you can try a injector cleaner when u next tank your car and see if it improves the mpg or one or all of them may need replacing.

[skymaster]

Would either of these manifest themselves in any other way? A lack of power or lumpy idle? Mine seems to be OK in terms of power. Although without driving an identical car back to back how is one meant to know what is 'right'

If I wanted to ckeck to see if these things were at fault how would I go about it?

[vaslam1986]

Would either of these manifest themselves in any other way? A lack of power or lumpy idle? Mine seems to be OK in terms of power. Although without driving an identical car back to back how is one meant to know what is 'right'

If I wanted to ckeck to see if these things were at fault how would I go about it?

In terms to power you should be ok...but im pretty sure both problems will show up as being lumpy on cold and idle. your best bet would be to get it on the VAG-COM and get the fault codes. I'm sure someone on here would be more than happy to help you.

Sorry I couldn't be of any further help.

[skymaster]

Could thermostat be playing up? Does anyone think?

How long should it take for this engine to warm up to normal operating temperature? I find I have to drive for at least 20 mins before the needle is central in the temp gauge..

[andyroo]

Well i've filled up now and low and behold MPG is the usual 36:( What next i've run the vag on it and there are no faults showing but as I keep pointing out this is a normal run of the mill car not an F1 so no where near all parameters are monitored. These so called"technicians" do not seem to able to think beyond "the computer says no".

[skymaster]

I think my problem could be a stuck open thermostat. My engine seems to take forever to get warm. I drove roughly 5 miles on thursday to my mates garage. He opened the bonnet and the coolant was stone cold, radiator stone cold and also a pipe he expected to get hot was also stone cold. He thinks problem could be due to this and has reccomended fitting a new thermostat.

[skymaster]

Roughly how long does it take for your TDI 130 engine to reach full running temperature?

[Teutonic_Tamer]

I think my problem could be a stuck open thermostat. My engine seems to take forever to get warm. I drove roughly 5 miles on thursday to my mates garage. He opened the bonnet and the coolant was stone cold, radiator stone cold and also a pipe he expected to get hot was also stone cold. He thinks problem could be due to this and has reccomended fitting a new thermostat.

Good heavens, a diesel could reasonably take longer than 5 miles to reach normal operating temperature in this weather!

The fact that the rad was stone cold actually proves the thermostat is OK. They are held closed by a hoofing great spring, and hot water causes a sealed wax pellet to expand, pushing the stat open beyond the spring pressure.

Simple test, but long winded, and DISCLAIMER - keep scarves, neck ties, animals and children away from moving engne parts. From a stone cold start, start the engine. Whilst it is ticking over, lift the bonnet, look for the large coolant hoses which go to the rad. One will be near the top of the rad on one side, the other will be near the bottom on the opposite side. Now look for two smaller diameter hoses headding into the bulkhead - these supply the interior heater. Carefully feel all hoses, they should all be cold. Sit in the car, watching the temperature gauge. As soon as you see it rise, check all 4 main hoses. The two smaller heater hoses should get warm first. The larger hoses to the rad will remain stone cold, until the temp gauge is very close to the normal temp. The heater hoses should get hotter and hotter. When the temp gauge does get near the norm, the top hose to the rad will suddenly get warm very quickly, as the thermostat reaches the required temperature, opens, and allows the now hot water to the radiator. The bottom radiator hose should soon get warm after this.

That is perfectly normal cooling system operation, and is perfectly common for the radiator to remain stone cold after relatively short journeys!

Sadly, if you want your interior to warm up quicker in the winter, get heated seats, or a petrol engine!

Rgds

[skymaster]

nicely explained, thanks!

Maybe my mechanic mate needs Some lessons from you! I am just guessing and taking his advice. This is the first TDI I have owned having been a petrol head for most of my driving career. I did just expect a bit more MPG from it.

[Teutonic_Tamer]

All engines take a dip in fuel consumption in this weather - petrol or diesel.

It takes longer for the car to reach normal operating temperature.
The wind chill through the radiator and engine compartment is more severe.
You will be taking more heat from the heater.
You will no doubt have your lights, heated rear screen, heated mirrors, heated seats, wipers, blower fan - all much more than the summer.

All these put extra demands on the engine, in more ways than one. :approve:

Rgds

[El Dingo]

I have a B7 A4 2.0TDI, and get no better than 40mpg with an egg under my right foot... Car is booked in, I'll let you know...

[Teutonic_Tamer]

Maybe my mechanic mate needs Some lessons from you!

Are you sure your mate is actually a qualified mechanic?? I ask, because the detail I posted in reply #10 is basic cooling system operation, applicable to any car (or van or truck or bus)! I'm sorry to say it, but it's people like that which give the garage trade a bad name!

Rgds

[skymaster]

Yea, he is qualified but what can I say..... He did his apprentiship in a main dealer so was fully trained to do a service in 30 seconds flat and not a lot else.

At the main dealer he came from they were trained as service technicians and fitters. Mechanics were a thing of the past in that workshop.

[Teutonic_Tamer]

Yea, he is qualified but what can I say..... He did his apprentiship in a main dealer so was fully trained to do a service in 30 seconds flat and not a lot else.

At the main dealer he came from they were trained as service technicians and fitters. Mechanics were a thing of the past in that workshop.

So he is basically a "one make, dealer service technician" - and if the "computer" doesn't tell him what is wrong, he is stuffed, and clutching at straws.

I had a big run-in with a so-called "workshop foreman" at one of my local franchised dealerships, which is yet to be resolved!

In another really notable incident many years back, we had a 1990 Cavalier with ABS - the ABS warning light came on, as I didn't have access to the proper diagnostic kit (GM Tech2), I took it to the local Vauxhall dealer to investigate whilst I waited. Ten minutes later, some cocky $h!te came back and said "Oi, your car ain't got ABS, what you wasting my time for?". A discussion developed, and er... elevated, disturbing other customers who were also waiting. A workshop foreman intervened, telling me I didn't know what I was talking about. At this stage, I was getting rather livid, and spitting blood. I invited them both to join me on a visual, under-bonnet inspection of our Cavalier - I pointed out to them the Bosch ABS modulator, clearly visible and bolted on a bracket near the battery, and said to them both, "tell me again it does not have ABS?" The cocky $h!t replied, "it aint on my computer, so I can't fix it" I turned to the "foreman", who just shrugged his shoulders, told the sprog to unplug it, park the Cav outside, and me to wait in the waiting area. A few minutes later, they had the cheek to present me with a bill - another argument developed, me refusing to pay. I got some of the other waiting customers involved, and the names and addresses of two of them. I walked out without paying, and a couple of the other customers followed before any work was carried out on their motors. The following day, their service manager phoned, threatening me for non payment, after another "discussion", I told him to issue a court summons, were I would call these witnesses, and would publish the results of my "victory" in the local and national press (the dealer was part of a national chain). Needless to say, they took no further action, I found an independent Bosch specialist, the problem was diagnosed in 15 minutes with a full printout, and yours truly fixed it the following day!

Now you need wonder no more why I have so little time for franchised dealer service departments, and the muppets they employ!

Rgds

[skymaster]

Tell me about it! I used to have the pleasure of being the poor guy that faced the customers while severe muppetry went on behind the workshop door! That was such a nightmare job. I was not from the old school 'main dealer' way of thiking and I found it very frustrating working with these guys.

Some of the rank incompetence of the guys on the tools was shocking. I think the characters in the Beano stood a better chance of fixing faults! Sometimes arguments with customers went on and on. The reason they were so keen to never admit defeat was because it would hit their time / efficency bonus figures for that month. If we were short of bonus near a month end every effort would be made to get the hours sold up. Inc charging to fit bulbs, upselling more brakes, cambelts, exhausts, bushes, etc etc.

Not good

[skymaster]

Oh yea, Just remembered why I cam on the forum. Going back to the original post. I took my car on a 100 mile trip yesterday, some motorway but also some a roads. Averaged 41 mpg (according to trip computer) with climate on econ and very light right foot.

Used cruise control on Mway set at about 75 mph. Drive was from Bath to Milton Keynes.

Being a TDI I did expect better but I am willing to accept my expectations could be too high???

[Teutonic_Tamer]

Tell me about it! I used to have the pleasure of being the poor guy that faced the customers while severe muppetry went on behind the workshop door! That was such a nightmare job. I was not from the old school 'main dealer' way of thiking and I found it very frustrating working with these guys.

Some of the rank incompetence of the guys on the tools was shocking. I think the characters in the Beano stood a better chance of fixing faults! Sometimes arguments with customers went on and on. The reason they were so keen to never admit defeat was because it would hit their time / efficency bonus figures for that month. If we were short of bonus near a month end every effort would be made to get the hours sold up. Inc charging to fit bulbs, upselling more brakes, cambelts, exhausts, bushes, etc etc.

Not good

Touché :D

It is for exactly those reasons why you should avoid main dealers, and national chains such as Halfraud$, and tyre places, and find a good reputable independent VAG (or Reno, Toyota, insert any other make here) specialist.

These independent specialists are often one or two man/men bands, or family businesses, with their personal reputations vital for their own livelyhoods. They are frequently factory trained former main dealer tecchys, who have "seen the light", and wish to concentrate on an honest, reliable, customer focussed, high quality service, where things like bonuses and targets are a foreign language!

[Teutonic_Tamer]

Oh yea, Just remembered why I cam on the forum. Going back to the original post. I took my car on a 100 mile trip yesterday, some motorway but also some a roads. Averaged 41 mpg (according to trip computer) with climate on econ and very light right foot.

Used cruise control on Mway set at about 75 mph. Drive was from Bath to Milton Keynes.

Being a TDI I did expect better but I am willing to accept my expectations could be too high???

I think that is quite reasonable for this time of year. Don't forget, winter diesel has additives, which may alter its' thermal efficiency (can't remember exactly ATM, I've got a barsteward of a headache! :( )

Dont forget (2), the A4 is quite a heavy beast - its' not like a Nissan Micra diesel, and aint gonna achieve the same economy figures! ;)