I have a T reg K11 1.3i which seldom gets more than 38MPG. Sometimes only 35. Is this unusual?
can anyone comment or suggest, please?
Here's the full story, if anyone is interested:-
I do a 10 mile run to work and back, on fairly empty A/B roads for 9 miles of the 10. There are a couple of steepish hills on the route, but otherwise not much need for wasting fuel on braking.
Checked so far (not in order) :-
Fresh oil and filter
Recent new front brake calipers, not dragging (and some brilliant slotted Brembo discs--recommended!)
Plug gaps are correct. Plugs about a year old, but changing them last year didn't change anything.
No misfires (it has never missed a beat hot or cold)
Performance is good--better than I expected, if you change down 2 or 3 gears
I try not to use the performance when I'm checking the MPG. Previous owner was a little old lady who drove at 30mph on fast roads (grrr!) and also straight past the gates of the primary school at 3:30pm (GGRRR!)
New NTK (same as NGK?) Lambda sensor fitted recently.
Always Shell unleaded fuel (also tried V-power--very smooth running, lots of go when i revved it but mpg was worse still). I had a bad experience with supermarket fuel, so I've used Shell unleaded for a year now.
I've run it up with Conzult software and the adaptor lead. It shows the Lambda sensor cycling. I also used an oscilloscope and it shows a nice healthy Lambda heartbeat as far as I can see. But I don't know how fast it should be cycling. (I know electronics and the theory, but I don't have experience of these systems, so I might as well be clueless:blush
Conzult shows water temp about 80C and there's a lean/rich indicator in the software which flickers but spends more time at 'rich' than 'lean'. There are various other indicators including injector cycle time in mS, which I don't know to judge.
The last Lambda sensor was a year old and it looked a bit sooty to me. And the excellent performance/response and exhaust smell suggest it's running a wee bit rich.
Both times when I changed the Lambda sensor, the throttle response was very good (too good, almost snappy) for the first bit when taking off, making it hard to get a smooth start. When I changed the sensor, the throttle response on part throttle calmed down a bit, which I took as a good sign of an economical fuel mixture. Was I wrong?
The car is standard, apart from 185-60/14 tyres on Passat wheels. It raises gearing slightly (just enough to correct the speedo, that's all). I only put the aircon on once a week for a minute, or when the windows steam up in bad weather.
I don't know what else to try. For 38MPG I might as well fit a Primera GT engine and have some extra fun
can anyone comment or suggest, please?
Here's the full story, if anyone is interested:-
I do a 10 mile run to work and back, on fairly empty A/B roads for 9 miles of the 10. There are a couple of steepish hills on the route, but otherwise not much need for wasting fuel on braking.
Checked so far (not in order) :-
Fresh oil and filter
Recent new front brake calipers, not dragging (and some brilliant slotted Brembo discs--recommended!)
Plug gaps are correct. Plugs about a year old, but changing them last year didn't change anything.
No misfires (it has never missed a beat hot or cold)
Performance is good--better than I expected, if you change down 2 or 3 gears
I try not to use the performance when I'm checking the MPG. Previous owner was a little old lady who drove at 30mph on fast roads (grrr!) and also straight past the gates of the primary school at 3:30pm (GGRRR!) New NTK (same as NGK?) Lambda sensor fitted recently.
Always Shell unleaded fuel (also tried V-power--very smooth running, lots of go when i revved it but mpg was worse still). I had a bad experience with supermarket fuel, so I've used Shell unleaded for a year now.
I've run it up with Conzult software and the adaptor lead. It shows the Lambda sensor cycling. I also used an oscilloscope and it shows a nice healthy Lambda heartbeat as far as I can see. But I don't know how fast it should be cycling. (I know electronics and the theory, but I don't have experience of these systems, so I might as well be clueless:blush
Conzult shows water temp about 80C and there's a lean/rich indicator in the software which flickers but spends more time at 'rich' than 'lean'. There are various other indicators including injector cycle time in mS, which I don't know to judge.
The last Lambda sensor was a year old and it looked a bit sooty to me. And the excellent performance/response and exhaust smell suggest it's running a wee bit rich.
Both times when I changed the Lambda sensor, the throttle response was very good (too good, almost snappy) for the first bit when taking off, making it hard to get a smooth start. When I changed the sensor, the throttle response on part throttle calmed down a bit, which I took as a good sign of an economical fuel mixture. Was I wrong?
The car is standard, apart from 185-60/14 tyres on Passat wheels. It raises gearing slightly (just enough to correct the speedo, that's all). I only put the aircon on once a week for a minute, or when the windows steam up in bad weather.
I don't know what else to try. For 38MPG I might as well fit a Primera GT engine and have some extra fun
