Can anyone help?

 

I usually have the "average" consumption displayed but yesterday I switched to "Consumption".

 

The display varies from say 55mpg to 200mpg to blank and other values in between and never settles on a steady value.

 

Is this a fault or do I need to reset something.

 

Any advice

It's what the car is actually using (with a time lag of about 3 or 4 seconds)
No problem at all if average consumption is about right.

Edited 24 July, 20169 yr by Urrell

It will also show --- when on the over run as no fuel is injected and you can't divide by 0.

You can 'make' petrol going down a mountain if you want to believe it.

The measurement has a very short sampling cycle, maybe two seconds or so, so the values are very erratic (not erroneous!). This is the nature of the beast, and not a fault. It also makes the indication almost useless. It would be nice to have the ability to lengthen this cycle to maybe a minute or so, which would make it much more useful.

When driving in constant conditions, Cruise Control on and same gradient the real-time consumption is really fixed. When driving in town it goes up and down like crazy so it's useless. 

This is the nature of the beast, and not a fault. It also makes the indication almost useless.

 

 

When driving in town it goes up and down like crazy so it's useless. 

It's not useless it tells you what is happening at the time, full throttle, less throttle, uphill, downhill, headwind, tailwind etc  it tells you what is happening. It's only useless if you don't understand what causes it to read what it does. It can help economy by seeing what gives better mph like what gear to run in etc.

It's not useless it tells you what is happening at the time, full throttle, less throttle, uphill, downhill, headwind, tailwind etc  it tells you what is happening. It's only useless if you don't understand what causes it to read what it does. It can help economy by seeing what gives better mph like what gear to run in etc.

 

Quite, but it appears a lot of people don't understand that.

Anyone else remember the old vacuum gauges, working off the inlet manifold? 

Anyone else remember the old vacuum gauges, working off the inlet manifold?

Yes

Essential on some piston engine aircraft but other than a short term fascination, not much use on a car.

It was claimed you could diagnose a burnt valve I seem to recall.

Anyone else remember the old vacuum gauges, working off the inlet manifold? 

 

What about the vacuum wipers working off inlet vacuum, especially when going at speed in the rain with little vacuum and then when stopped and the wipers not really needed going 10 to the dozen

What about the vacuum wipers working off inlet vacuum, especially when going at speed in the rain with little vacuum and then when stopped and the wipers not really needed going 10 to the dozen

You controlled their speed with the go pedal.......bad luck if you were overtaking though.

The measurement has a very short sampling cycle, maybe two seconds or so, so the values are very erratic

 

Not "erratic", merely variable - as it should be.

 

It's not useless it tells you what is happening at the time, full throttle, less throttle, uphill, downhill, headwind, tailwind etc  it tells you what is happening.

 

Quite so.  A number of instruments on the vehicle do this.  For example, there are two speedometer displays which tell you what is happening at the time ie how fast you are going.  For those who find this concept difficult to grasp, I would recommend selecting the average speed display on the Maxidot...and explaining that to the magistrate when you try to challenge your SP30.

^^^^comparing average speeds would be interesting.

In Melbourne mine was ~ 45 kph but in the country it's high 60s.

Thanks for making it clear to me!

 

Paul

Anyone else remember the old vacuum gauges, working off the inlet manifold? 

 

Got one on the Lomax..........................

 

 

 

 

 

 

 

 

 

It doesn't work!

.....It doesn't work!

 

Did they ever?!