alex88
Guest
just noticed over the weekend that drivinfg motorway speeds on cruise control returns about 42-43mpg ish where as using my foot i i get 47ish mpg. Is this normal?
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Jonboy582
Guest
Not sure if it can be called factual. But Jeremy Clarkson said he got more MPG when he turned the cruise control off in that audi A6 he drove to Scotland and Back. I guess as you can tell what the road is doing ahead you can adjust your driving style accordingly.
RobTheHood
Guest
Fuel cleaner worth a try?? worked for me (+4mpg or thereabouts) And use decent fuel, i've switched to shell from tesco for example
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I have a pd 100 and i was getting roughly 44mpg, but now since the cold weather im getting 35mpg......its just had its 1st service as some people told me it cuda been that, but my suggestion would be cuz of the weather....not sure tho
RobTheHood
Guest
Wow I'm amazed at how many people have viewed this thread!
A question really, if you use your trip computer how accurate is it? I sort of rely on mine but I know it lies slightly. If my trip com says 65mpg for example the fuel left message doesn't correspond exactly. Its fairly accurate towards the end of a tank but at first it adjusts like crazy!
I'm unsure how to score an accurate result apart from fill the tank and reset the trip clock. Doing that my trip clock over estimates all the time. Obviously its how you drive ur car which decides its efficiency
Rule of thumb i'd say is record the fuel you put in and miles done but allow for jams and such, I get a (worked out) figure of 54mpg average. Computer says 57mpg overall average so actually not that different but is that based on 3000miles or somthing?
A question really, if you use your trip computer how accurate is it? I sort of rely on mine but I know it lies slightly. If my trip com says 65mpg for example the fuel left message doesn't correspond exactly. Its fairly accurate towards the end of a tank but at first it adjusts like crazy!
I'm unsure how to score an accurate result apart from fill the tank and reset the trip clock. Doing that my trip clock over estimates all the time. Obviously its how you drive ur car which decides its efficiency
Rule of thumb i'd say is record the fuel you put in and miles done but allow for jams and such, I get a (worked out) figure of 54mpg average. Computer says 57mpg overall average so actually not that different but is that based on 3000miles or somthing?
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I find the trip computer overestimates, but only by 3 mpg at worst (according to my logs). I record fill quantity and odometer mileage at each fill
Deleted member 28319
Guest
Mpg on my car's taken a nose dive since the cold weather. My trip to work is 9 miles and i take 2 routes, 1 heavy stop start traffic and then 6 miles of motor way at about 55-65 mph and for this the trip shows about 47-48mpg which i know is about really 44 mpg.
The other route is light back road traffic which my trip show 43-44 mpg. My temp gauge at the moment does'nt hit 90 till i'm half way to work on either route, and after changing all the usual low mpg consumables and regularly using millers SP4 i've just come to the conclusion that my car isn't as economical as i thought it would be when i bought it in Feb, and that in the cold weather i can expect to loose about 7-8 mpg.....
The other route is light back road traffic which my trip show 43-44 mpg. My temp gauge at the moment does'nt hit 90 till i'm half way to work on either route, and after changing all the usual low mpg consumables and regularly using millers SP4 i've just come to the conclusion that my car isn't as economical as i thought it would be when i bought it in Feb, and that in the cold weather i can expect to loose about 7-8 mpg.....
chapelhill
Guest
In my experience of te older tdi's the maf sensor can increase your consumtion. If the maf sensor is underestimating the air into the engine then the ecu will request more boost to get to the right amount of air under light throttle conditions. The maf can fail on its own, or by the connector which I presume is why some people use the dialectric for the contacts.
Creating more boost than neccessary wastes energy and hence increase fuel consumtion. In my experience this was causing approximately 4mpg at motorway cruising speeds.
Under inflated tyres can have 1-2mpg impact and tired thermostats can also have an effect especialy on the shorter journeys.
On the TDI club forums there were repated cases of maf sensors failing when used with K&N filters, but how much of that was due to over oiling I cannot say. I have seen plenty of people using the green pannel filters are these oiled? My old passat had an oild film on the MAF through 130k miles, cleaned it off (not recommended) and improved mileage.
I would guess cruis control will give slightly worse economy than using the right foot as it is better at maintaining the speed and will probably do the journey slightly faster, I can see no reason if all other parameters are equal at a typical 70mph.
How much impact does the air conditioning have at 70mph speeds?
Regards
Chapelhill
Creating more boost than neccessary wastes energy and hence increase fuel consumtion. In my experience this was causing approximately 4mpg at motorway cruising speeds.
Under inflated tyres can have 1-2mpg impact and tired thermostats can also have an effect especialy on the shorter journeys.
On the TDI club forums there were repated cases of maf sensors failing when used with K&N filters, but how much of that was due to over oiling I cannot say. I have seen plenty of people using the green pannel filters are these oiled? My old passat had an oild film on the MAF through 130k miles, cleaned it off (not recommended) and improved mileage.
I would guess cruis control will give slightly worse economy than using the right foot as it is better at maintaining the speed and will probably do the journey slightly faster, I can see no reason if all other parameters are equal at a typical 70mph.
How much impact does the air conditioning have at 70mph speeds?
Regards
Chapelhill
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I've owned my Leon PD150 for 3 years and in that time have never returned over 50mpg, ever!
It's re-mappped, has a Green panel filter and I have always used BP Ultimate Diesel, tyre pressures are checked at least weekly, my daily commute to work is 23 miles each way, if the traffic is kind in warmer months I may return high forties (sorry my numeric number four button on the laptop is fudged due to a tea spillage by small child!)
However, taking today as an example, traffic to work was pants and the temp wasn't too bad at about 3.5', I averaged 38.2, I never had the chance to drive enthusiastcally due to the volume of traffic, this is my "normal" return on a daily basis....
I do follow what many people post stating 50-60 mpg and have wondered if this was actually correct or, if my car was suffering issues???
It doesn't concern me too much though as it's a damn sight more than I used to get from my Jaaba'd 02 plate Cupra R I owned in time before kids! Four hundred quid a month on Optimax was painfull.
Now, even with my Cupra tdi averaging relatively low figure, I return Four50 (damn button!) mile per fill up which isn't too bad, and it's all relevant anyway.
One additional snippet maybe of note, is that in between my Cupra R and my current Leon Cupra pd150, I actually had ab Altea 2.0tdi sport (manual not dsg) now the fuel economy on this was truly pants, no re-map, just a standard car and the same journeys I still use today only gave me fourty 1 ish (need to sort this key out), motorway driving with cruise was awful, Weston S Mare to Taunton on M5 2 adults and 1 child, cruise set to 70 returned between 38 to fourty1 ish (I kept a log for a few weeks)
It's re-mappped, has a Green panel filter and I have always used BP Ultimate Diesel, tyre pressures are checked at least weekly, my daily commute to work is 23 miles each way, if the traffic is kind in warmer months I may return high forties (sorry my numeric number four button on the laptop is fudged due to a tea spillage by small child!)
However, taking today as an example, traffic to work was pants and the temp wasn't too bad at about 3.5', I averaged 38.2, I never had the chance to drive enthusiastcally due to the volume of traffic, this is my "normal" return on a daily basis....
I do follow what many people post stating 50-60 mpg and have wondered if this was actually correct or, if my car was suffering issues???
It doesn't concern me too much though as it's a damn sight more than I used to get from my Jaaba'd 02 plate Cupra R I owned in time before kids! Four hundred quid a month on Optimax was painfull.
Now, even with my Cupra tdi averaging relatively low figure, I return Four50 (damn button!) mile per fill up which isn't too bad, and it's all relevant anyway.
One additional snippet maybe of note, is that in between my Cupra R and my current Leon Cupra pd150, I actually had ab Altea 2.0tdi sport (manual not dsg) now the fuel economy on this was truly pants, no re-map, just a standard car and the same journeys I still use today only gave me fourty 1 ish (need to sort this key out), motorway driving with cruise was awful, Weston S Mare to Taunton on M5 2 adults and 1 child, cruise set to 70 returned between 38 to fourty1 ish (I kept a log for a few weeks)
alex88
Guest
Just tieing on sumthing from another thread about problems with ibiza cupra tdi's stalling extreamly easy when first sarted from cold. I have a problem with this as did a few other people. One guy mentioned he had his temp sensor changed which solved the problem. Could a problem with the temp sensor be causing low mpg. as im still acheiving around 40mpg doing mainly duel carrage way and a road driving even when trying to drive economicaly.
I am ao having similar problems.
At one point, I want managing high fifties, even 60.1MPG out of my Sport TDi (Ibiza), but now I haven't seen over 52 in a long long time.
Car has done 90k now, is it time for a MAF change?
The brakes will be getting done soon as well... does look like the pad is touching the disk at the moment...
Sat at 75 on the cruise control, I can't manage any more than 47MPG, now, IMO, thats piss poor?
At one point, I want managing high fifties, even 60.1MPG out of my Sport TDi (Ibiza), but now I haven't seen over 52 in a long long time.
Car has done 90k now, is it time for a MAF change?
The brakes will be getting done soon as well... does look like the pad is touching the disk at the moment...
Sat at 75 on the cruise control, I can't manage any more than 47MPG, now, IMO, thats piss poor?
chapelhill
Guest
A quick check for the temperature sensors is to use vag.com lead to check that all the sensors read ambient temperature when the engine is completely cold and then check temperatures when it is fully earm to see tht they are within specification.
The only real way to check the MAF sensor would be to either try somebody elses (how much are these new?) or to establish what the boost pressure should be for say cruise at 70mph on flat road. When I cleaned my passat MAF sensor I notices a drop in boost pressure of about 2-3 psi for 70mph cruise position. I don't have a boost gauge, but I will try to get some readings from VAG.com this weekend.
I have spent time fixing airbox as it was loose and dialetric for the connector to the MAF sensor, but I cannot determine any difference. I will try PD160 intake and new airfilter next.
I think I am getting about 52mpg actual 55mpg indicated when cruising at 70mph. I was hoping for closer to 60mpg as I used to get 47mpg from my Volvo 850tdi estate which is alot larger and heavier with older VP37 type of diesel injection.
Regards
Chapelhill
The only real way to check the MAF sensor would be to either try somebody elses (how much are these new?) or to establish what the boost pressure should be for say cruise at 70mph on flat road. When I cleaned my passat MAF sensor I notices a drop in boost pressure of about 2-3 psi for 70mph cruise position. I don't have a boost gauge, but I will try to get some readings from VAG.com this weekend.
I have spent time fixing airbox as it was loose and dialetric for the connector to the MAF sensor, but I cannot determine any difference. I will try PD160 intake and new airfilter next.
I think I am getting about 52mpg actual 55mpg indicated when cruising at 70mph. I was hoping for closer to 60mpg as I used to get 47mpg from my Volvo 850tdi estate which is alot larger and heavier with older VP37 type of diesel injection.
Regards
Chapelhill
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