VR6 Accurate MPG Computer Shocker

[AlexDG 0]

Just thought I would share my astonishment at the accuracy of the mpg computer, never really checked it properly before, but after a pump to pump 300 odd mile trip the other day I checked what the computer was claiming...computer said 35.8mpg, real world figures said 35.4mpg!

 

Equally surprisingly was the computer showing 37.1mpg at the end of the return journey, mostly motorway, but also about 50 miles of A-roads generally all at about the speed limit and maintaining a stead speed, but including several foot to the floor overtakes...not bad for an 18 year old car.

 

(The car is bog stock and has recently had the majority of sensors replaced and new plugs, leads, dizzy cap & rotor arm, which probably explains the relatively good fuel economy.)

[Human Joist 10]

That and the fact it's a big engine in a light car so once your up to speed you won't use much to keep it going unless you press the loud pedal.

[Kevin Bacon 5]

Hmmm, they're not light cars for their size imo. I put mine on the weighbridge some years ago and it was 1320kg. At that time, the only mods were 17s and a Supercharger. The 1210kg handbook figure is complete cobblers!

[Human Joist 10]

Sorry Mr Bacon. I should have said in comparison to the cars we use at work. It's a BMW 5 series with 3.0 petrol and weighs in at 2.2 tonnes to me the raddo feels light like a go cart.

[Roger Blassberg 0]

Sir Isaac Newton tells us that the weight of the car doesn't matter much at constant speed, it's the shape, the frontal area and the speed that affect the fuel consumption.

 

I have similar experience of the accuracy of the MFAs having owned VWs with them for more than 25 years starting with a Mk2 Golf GTi and now with a B4 Passat and a VR6 Corrado. Checking over several weeks, the MFA is accurate to within 5%.

 

I recently saw 42.8 mpg over a 40 mile journey on A40/M40/M25 in the VR6, admittedly pussy-footing along at no more than 55-60. I have had the injectors cleaned andf refurbished and that makes a very substantial improvement.

 

Best wishes

 

RB

[AlexDG 0]

I was going to replace the injectors, but at £180...each! I will be waiting for a convenient time to have the existing ones cleaned.

[Human Joist 10]

Have you tried pricing them up at euro car parts. Theirs will be Bosch and may be much cheaper. I also have a trade account there so I could always get them cheaper and post to you.

[VW_chris 10]

i get an average of around 7-12 MPG on my display, im wondering if anyone could point in the direction of a faulty sensor or anything like that?

[Billzeebub 1]

Quite reassuring that MFA are reasonably accurate. I have never been that bothered to workout my fuel economy. The MFA shows an average of 25.8. Most of my driving recently has been around town so I'm well happy with that. On motorway/open road journeys it is usually hovering around 35mpg+

[AlexDG 0]

i get an average of around 7-12 MPG on my display, im wondering if anyone could point in the direction of a faulty sensor or anything like that?

 

How do you drive it? Using the loud pedal enthusiastically will reduce the MPG significantly.

 

Is it regularly serviced, has everything been changed iaw schedule?

 

Other than that being stuck on the cold running map this time of year will cause reduced MPG. Either faulty thermostat or temp sender can cause this (if thermostat the engine really will be 'cold' and will show as such on the gauge).

 

Binding or dragging brakes will also cause MPG to fall, especially if all corners are in need of a refurb.

 

Have you checked for any engine fault codes.

 

I dare say there are a multitude of other things it could be, but I think they are the main ones.

 

---------- Post added at 10:15 AM ---------- Previous post was at 10:14 AM ----------

 

Have you tried pricing them up at euro car parts. Theirs will be Bosch and may be much cheaper. I also have a trade account there so I could always get them cheaper and post to you.

 

Thanks for the offer, but I am in the 4x4 most of the time now that the winter weather is with us so it won't be a problem getting the existing injectors out and sent away.

[VW_chris 10]

there are days when i go out in the car to drive it, and i do give it some boot. but most days i just cruise around in 5th in low revs.

 

it has been serviced with OCD, and im not the first, ive got a service history for the car which fills a folder. ive had the car nearly 3 weeks now and ive allready given it a full service (2nd time in under 5k). i work in a garage and my other car a 1.6 mk4 golf, which ive maintained with the same level of care and thats just under 173k.

 

it warms up to the correct temperature and stays there, ive had the thermostat go on my golf and 2 coolant temp senders and i know the trouble they can cause, just with the mk4, the same sensor gave dodgy readings to the coolant temp on the clocks, which i dont get on the vr6, also, i had it on the scanner at work today which threw up a code for the engine speed sensor, however i went into live data and found there to be nothing wrong with the part and it looks fairly new, which tells me the code proberly hasnt been deleted.

 

ive had all the wheels off to remove and clean up the calipers, and i know that none of the calipers are binding on. it just seems odd to me that the faults which could cause a low mpg reading, arnt there :s which is why im lead to believe the readout on the clocks might be wrong, so im wondering what else could cause it

Edited December 7, 2012 by VW_chris