2.2 hdi MPG improvement

[Monkeyfeet]

During last weekend I replaced the swirl valve actuator on the C5. This job involves taking off /moving hoses, wires, airbox etc to get at the mounting bolts for the little blighter so whilst there I cleaned the carbon bunging up the manifold end of the s/s exhaust gas recirc pipe and sealed the flange jobby with exhaust paste (oily grease has been slowly dripping out onto the starter motor).
So, first time out was yesterday, a run up to Lincoln from home (nr Luton), a 240 mile trip including a detour into Milton Keynes. now thanks for bearing with me here, 'cos I'm very happy but slightly bewildered to report 54.4mpg - my personal record for that kind of trip. ok alot was on a the M1/ a46 with c/control set to 67mph but even so?
It was about 43mpg before! I know I really need about a 1000 mile of mixed driving to prove anything, it's just that it's never got quite that high before. Had to hold 55 constant.
So did I tighten down a loose hose or something? Especially since I'm sure I unticked EGR option in Ecusafe when removing the DPF. Prior to this average mpg had been slowly falling.....
ps swirl valve lever was held closed prior to this. (for about 3 years!) 2100rpm / 65 in top it they opens.

[Peter.N.]

I have had a similar experience, the best consumption on mine was 49.6 at a steady 60mph on the motorway, II recently cleaned the MAF which seemed to give a slight improvement but a week or so ago I put a can of EGR cleaner through it, the next journey I made to Axminster it showed over 60 mpg! it is mostly down hill though, by the time I got home it was showing mid '40s but I had done a lot of stop start work. We are going to Yorkshire in it next month so will be able to give it a proper test, because of the poor consumption I was going to change it for a 2.0L but if it gives something in the '50s I will probably keep it.

Peter

[Monkeyfeet]

Hi Peter,
I remember reading your post before re mpg for the 2.2 when my highest ever was 50.5 on a Luton - Durham round trip last year so thought that you must be even more careful than me on an extra-careful day! After yesterday I can now certainly see where you're coming from on this subject. One thing that does make the mpg suffer hugely are the shopping trips into MK and Luton that 'er indoors uses it for sometimes. Not that she's a heavy footed driver, the engine really does not seem to appreciate stop/start slow traffic one little bit. It's certainly made for eating comfy distances though.

[Peter.N.]

I have the same problem, when my wife has been driving the 406 the mpg tumbles, its not just that she doesn't have my 'light touch' but she usually uses it fairly locally and for shopping, stop start driving takes a heavy toll. At least you can park relatively easily in MK or at least you could last time I was there. We have only been using the 406 locally for the last couple of months and the average is down to around 50mpg but it will allways do 60+ on a longish journey (at least when I'm driving it) but yes, I do drive painfully carefully, my brakes and tyres last a long time too.

Peter

[jgra1]

get them into online shopping and also hide the keys

[Peter.N.]

You haven't seen where we live