Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Auto Addict]

Mrs AA's Astra 1.8 automatic over a 384 mile round trip used 45.9 ltrs of fuel (10.0967 gals).

I make that 38.03 mpg.

Computer read 23.7 mpg.

Computer was reset before the round trip.

Obviously out of sync, can it be calibrated using a TechII?

[Taxi_Driver]

I dont know tbh, AA. I doubt it....

Fuel computers 'guess'. They certainly dont monitor the amount of fuel being used.

I believe they 'guess' by how often the injectors are being fired.

However ime if the engine isnt running 100% they get it wrong.......but usually the other way around.....ie claim more mpg than is actually the case.

edit....just to add...

I assume you brimmed it before the trip and did the same after the trip.....theres going to be inaccuracy in doing that.....i would get a reading after several thousand miles....be less of an 'error' then 

[TheBoy]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

[Taxi_Driver]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

Yes, as you guessed my comments where based on diesel experience....

They can also go inaccurate from not being thrashed.......

I kid you not.....try this one....

I borrowed a company VW Sharon a while back.......reset the fuel computer and the comp reckoned after a few days and several hundred miles it was doing circa 50mpg.....it wasnt....probably nearer 40mpg....few days later i was back in the garage having a bulb replaced....i mentioned this to the garage owner, that the fuel comp was miles out.

His remedy for this problem......started it up and revved it to the rev limiter for a good 2 to 3 mins.

He made comments about, some vehicles never go on a run, just driven in town....

Brave man! That engine had done 240k miles.....but it did the trick.....actual fuel comp went up to pretty much what the computer thought it was doing..... 

[Auto Addict]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

2005, 1.8 auto. 4 door hatchback, petrol.

[TheBoy]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

2005, 1.8 auto. 4 door hatchback, petrol.

Astra-H (the one that falls apart the more you stare at it)?  Hornby man has my CANdi, which the Astra-H needs, so try him

[mantahatch]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

2005, 1.8 auto. 4 door hatchback, petrol.

Astra-H (the one that falls apart the more you stare at it)?  Hornby man has my CANdi, which the Astra-H needs, so try him

Could not possibly fall apart quicker than a an Omega facelift interior soft feel trim 

[TheBoy]

Should be fairly accurate (computer gets injection duration signal from ECU). Petrols stay accurate, generally, even if buggering about with chav's wet dreams (FPRs, bigger injectors etc), as the ECU will trim back in response to lamdas.  Diesels can go inaccurate when messing with pump/pressures.

What version Astra?

2005, 1.8 auto. 4 door hatchback, petrol.

Astra-H (the one that falls apart the more you stare at it)?  Hornby man has my CANdi, which the Astra-H needs, so try him

Could not possibly fall apart quicker than a an Omega facelift interior soft feel trim 

Bits don't break or fall off the Omega. Wears badly, agreed, but not fall off

[zirk]

Some Volts fell off my battery the other morning on the mig.