Fuel filter...MPG?

[Tornado]

Most discussions of MPG suggest a dirty fuel filter can make the car use more petrol. How come?

 

[1275]

no idea, I keep forgetting all about changing mine, had the car 9 years now without changing it.

 

[plmval]

Dirty filter can restrict fuel supply, a lean air fuel mixture less than stoich fuel air ratio & thus inefficient running. Therefore to do the same amount of work, the vehicle uses more fuel.

 

[Tornado]

Of course we are all fans of a nice stoich ratio. But the lambda sensor should tell the ECU to make adjustment to keep the 14.7:1 ratio, no?
But I'm sure you are correct.

 

[fuzzy-hair-man]

Of course we are all fans of a nice stoich ratio. But the lambda sensor should tell the ECU to make adjustment to keep the 14.7:1 ratio, no?
But I'm sure you are correct.

Yes and no, the ecu can make adjustments in short and long term fuel trim (longer injector open or duty cycle) to get it right but there's a limit to those adjustments, at the extreme end if you just aren't able to get enough fuel through the filter it's not really going to matter how long you keep the injector open.

 

[DEdgeMac]

On my 300zx tt I had hesitation issues on/off boost. Tried all the usual and looked online and thought you know what the fuel filter looks a bit old and the lines are looking a bit hardened.

Changed the short length of lines and installed a new filter, ran beautifully and MPG went right up too.

Always worth checking- people don't usually consider them as possible issues and also forget to replace them at services.

 

[plmval]

Just common sense rational really, if it is starved of fuel it will not run at optimum efficiency & therefore to do the same amount of work, you will have to open the throttle wider to achieve the required work output, therefore increasing fuel consumption. You guys got the fuel flow drift.

 

[5949403030495959]

Where is the filter on a K11?

 

[Tornado]

On my 2002, it's on the right as you look in, between the engine and the firewall. I think...

 

[pollyp]

 

[1275]

a red cross marks the spot, can't see the photo myself for some reason

 

[pollyp]

a red cross marks the spot, can't see the photo myself for some reason

Damn msc app. Reupdated pic, try again

 

[Tornado]

Ah yes, there's that bad boy. Favourite brand/price?

 

[pollyp]

Ah yes, there's that bad boy. Favourite brand/price?

I just pop into motorfactors and ask for whatever generic fuel filter they have on system for a micra

 

[Tornado]

Gottcha. Thx.