Higher fuel consumption since an EGR valve replacement

argolis

I had a problem with an engine warning light last November or so. The garage said the EGR in my car (Focus mk2 1.6 diesel) needed to be replaced and did the job.

Before I got it done, my fuel consumption ranged from 4.9 to 5.3 l/100km, but taking it handy I was generally staying around the 4.9 mark. Since I got the EGR done, my consumption - still taking it fairly easy - won't go below 5.5 l/100km.

Is it possible for a crap EGR valve to increase fuel consumption? Could there be some other cause? Any thoughts appreciated

Thanks!

blackbox

Fuel consumption is usually worse in winter. Running cold for longer, rear window heater, more lights, etc.

biko

Are you reading from the dashboard computer?
Those numbers could as well be explained by cold or tyre pressure or other things.

Try this:
Fill up until the pumps clicks.
Set trip meter to zero
Drive until half tank is left, or less.
Then go fill up until pump clicks.
This time note down the amount of fuel used, and from trip meter note the distance driven.

This will give you real mixed fuel usage.
Check other cars of same model on fuelly and other sites and see how you compare.

argolis

Hey blackbox/biko,
Thanks for the responses!
That's a great idea biko, I'll do that, interesting website as well. I had toyed with the idea of something like in case the some fuel consumption sensor was wonky but I hadn't given any thought on how to go about it. 
Cheers!

George Dalton

Are you just going by the trip computer display?

The faulty EGR valve would have been affecting air flow readings which would mean that the trip computers calculations were based on incorrect information. So the fuel consumption most likely hasn’t changed. It’s just that the trip computer is now displaying the correct figure.

argolis

Yeah I was just going by the trip computer display on the dash. That's entirely possible, would have been nice to been able to do a "before" experiment :)
When I bought the car the previous owner had been averaging 4.9 l/100km (reportedly). I drove faster off the mark for a good while and it went up to 5.3l/100km, then when I started to take it easier it went back to 4.9 so I've just been assuming the readings worked correctly, as it was what I expected to see.
I'm going to measure the actual fuel consumption with biko's idea and see does it tally up with the dashboard display.
Thanks for the response!