Appalling fuel economy all of a sudden

[dusty23]

As above really.

Engine is 1.6 m40. Was running fine in terms of economy up until about 4 days ago. I say fine. About 120 miles for £20 with fuel at around £1.32.

I noticed it getting bad and then actually did a test. So £30 at £1.27 returned 96 miles!

Any suggestions. In my short ownership of this car it's never wanted for anything other than the weigh bridge! Serviced regularly etc etc..

Don't know about these engines really.

[jimbom30cab]

i'd check the resistance of the blue temp sender at the back of the ECU pins.

[dusty23]

i'd check the resistance of the blue temp sender at the back of the ECU pins.

How do go about that?

[rix313]

Out of interest did the fuel come from the same place? I notice that my range can”¦range”¦ from 380 to 420miles in my Clio if I buy from different places?

On the other hand my iS started to be a bit crap on petrol and I noticed that fuel was weeping around where the rubber pipe from the fuel tank joins the metal pipe which runs along the side of the car.

[Brianmoooore]

As rix313 is hinting at, the first thing to check is that you aren't leaving a trail of petrol!
Blue sensor test: wiki.

[dusty23]

As rix313 is hinting at, the first thing to check is that you aren't leaving a trail of petrol!
Blue sensor test: wiki.

no trail of petrol but will check for weaps,

Will check the blue temp sensor in the morning.

Could it be anything else while I'm tinkering?

Cheers

[Brianmoooore]

If the engine is operating way under its correct temperature, it will have the same effect as a failed 'blue' sensor.

[dusty23]

If the engine is operating way under its correct temperature, it will have the same effect as a failed 'blue' sensor.

It was, well at least it was indicating it, but I changed the viscous fan coupling a 6 or so thousand miles ago and that sorted that out.

[mattIS]

i know this is old thread but always check your o2 sensor.they can make a huge difference even tho they look fine.they help dictate air fuel mix by computer

[Brianmoooore]

Was going to post that this is probably irrelevant, since most UK E30s don't have lambda (o2) sensors, but if this is the 1993 316i lux touring lazur blue referred to in the OP's sig., then it will indeed have a lambda sensor.

[mattIS]

didnt know that being from oz,i thought we got euro spec cars here?anyway did this on missus nissan stagea and dropped consumption by 3l/100k's!