22.5 mpg from my DHSE

Hi all,

I've had my 2001 DHSE for about two weeks now and love it. I was quite impressed that the message display told me i've been running at 26.4 mpg, not too bad I thought.

Anyway over the last tank full I went for the more acurate brim to brim method and calculated the mpg. The reality is that it's only doing 22.5 mpg ! Does that sound about right for a diesel commuting to work, 30 miles each way, mixture of fast a-roads lots of corners, and some villages ?

I'm in the process of renewing all of it's bodily fluids (as I like to start off with a clean sheet with a new 2nd hand motor) but I don't think even that and the new air filter will get me much more mpg.

I had wondered that if someone has fitted a crap hot start fix i.e. no timed relay, maybe that is burning some fuel as the engine thinks it's cold. I'm clutching at straws though. How can I tell, is it in the ecu box if it's fitted ?

Any other ideas to improve the economy, or is it actually about right ?

Thanks, Rick

Assuming your calculations are correct, then 22.5mpg is alright for the average P38 diesel auto, I'd be a bit disappointed that the trip computer was so far out though.

My diesel has been idling a bit rough lately, and whilst I wasn't trying to solve that problem by putting some Redex in the tank, I've just noticed this morning that it is running a bit smoother after I did. I personally rate the stuff for giving the injectors a bit of a spring clean.

Thanks for the info. I think it's strange that the car mpg reading is so far out as well. Will double check with the next tank full.

I did consider adding an injector cleaner. Wasn't sure which one to go for though, or whether to just fill up with a tank of BP Ultimate diesel - or both (maybe not at the same time, don't want to scare it !).

Might go for Redex then as they don't sell the Millers Diesel power sport 4 in Halfords, which is the one i've heard some people recommend previously.

Check the injector leak off pipes, if they are weeping it has a bad effect on consumption and will eventually give you other problems.

Similar mpg on a 20 miles/40 min each way commute along A and B roads. Probably never goes over 50mph.

im doing about a 35-40 mile commute some a and b roads a bit of country roads thrown in and im getting 21-23 mpg. i thought it wasnt that good and have since change all fluids and filter but with not much improvement. Maybe my driving style needs adjusting!

Thanks all, sounds like mine isn't too far away from what opthers are getting then.

Will deffo check the leak off pipes though just in case, thanks Datatek.

if the glow plug light comes on when starting it after the engines up to temp its either got a hot start fix box on or the temp sensor is unplugged.

i get just under 24mpg from my dse,mind you im a dead slow driver,32 on a run so its not too bad your figures,they,r only slow as you have found out+they will drink it if you push them hard.THE trip computers on p38 are effin usless mine says im getting 12.5 mpg ffs,its doing double that ,mind you i dont do many long runs cos it wont go that far without breaking down.........lol...dave

PS i can recomend F E D injector cleaner ,its the only one ive used so far (cos i get it for nowt hhhhrrrrm) it does work ,you put it in a fairly full tank you think effin usless ,forget about it then two days later you think the motors going well i wonder whats up wiv it then you realise its the cleaner it definitly works,,,,,dave