MPG just dropped

[NikTheGeek]

CDT 2001. Normally get low mpg as I commute to work. Typically 30mpg but have had 50ish on a long motorway trip.

Anyway, I brim it every fill up and note the odometer reading, but these last 3 weeks its dropped off to 27mpg. However, performance seems ok, it doesn't ride any differently, acceleration is ok. The only thing I can think of is 4 new tyres at Kwik Fit at xmas when it had its mot. Would that account for a loss of 3mpg? Surely they wouldn't sell tyres that were *that* bad would they? I went for "midrange" ones, not the cheapest.

Anything else you can think of?

tnx

Nick

[Villa Villan]

Have you been using A/C in the mornings when demisting?, lights on more often, more use of heater recently, changed where you purchace your fuel or have you been watching The God Father?, if so check your boot ;) :shrug:. I am sure an oil burner expert will have an answer for you soon fella.

Cheers
Tony

[tvpcop]

Failing thermostat?

[8511swann]

Next time you go for a drive, when you stop, put the back of your hand against the wheels and see if any are hot. Maybe your brakes are binding.

[NikTheGeek]

Oh yes, forgot to add

I had the brakes replaced at xmas, but they'd be bedded in by now
I have the aircon on all the time always! :)
Probably have the heating set lower than normal, just 26'c as its not as cold as it has been.

I'll check the stat by putting the engine temp on the diagnostics but it is running up to temp as before and the cabin is warm enough.

Nick

[chris75]

26 deg ?:eek:
20 is hot for me ..........:}
How about the rest of you ?

[NikTheGeek]

Its been on 28 during December and occasionally on High. Normally on 25. I mean when it gets to summer, I might drop it to 23 or 22 on a really really hot day. And then I'll take my coat off too :)

[MalteseMarc]

[QUOTE=chris75;661810]26 deg ?:eek:
20 is hot for me ..........:}
How about the rest of you ?[/QUOTE

I have to say that is a very high temp, never have it higher than 21C myself, must be the warm mediterranean blood in me!:D

[rossocorsa]

do you have a fbh? nice way to eat diesel if you only do short runs

[Duotone]

If you have to set the temp to 26C [78.8F] its possibly your thermostat that's faulty.

Normally 21C [70.0F] is quite comfortable in a 75..

Dave T

[NikTheGeek]

If you have to set the temp to 26C [78.8F] its possibly your thermostat that's faulty.

Normally 21C [70.0F] is quite comfortable in a 75..

Dave T

Possibly, but it blows out nice and warm. I do have the FBH on twice a day at the moment, but I have since October so there shouldn't be a sudden change in the mpg.

One thing I haven't checked is if the new tyres are actually at the right pressure. They don't look under inflated, but I haven't checked.

Anyway, the car's done 58k and never had its maf changed or thermostat changed. Its an auto box, so I'm not sure if I'd notice a deteriorating maf as any poor acceleration when I plant my foot I'd put down to lag in the auto box. I've never driven another 75 so I have nothing to compare too...

Nick

[Dragrad]

Thread moved to correct forum. Re-direct left in old.

[rossocorsa]

as any poor acceleration when I plant my foot I'd put down to lag in the auto box. I've never driven another 75 so I have nothing to compare too...

Nick
that's almost certainly MAF I've still got the original bosch MAF on ours but with a synergy 2 with MAF compensation on and it'll spin it wheels from a stand still quite easily if you are harsh without it's quite flat. I agree the auto box masks the MAF issue you'll not believe the difference when sorted

[NikTheGeek]

that's almost certainly MAF I've still got the original bosch MAF on ours but with a synergy 2 with MAF compensation on and it'll spin it wheels from a stand still quite easily if you are harsh without it's quite flat. I agree the auto box masks the MAF issue you'll not believe the difference when sorted

Trouble is, real Bosch MAF's are expensive. Would any forum members care to comment on the ebay £30-£40 ones? I realise they may not last as long, but as long as they work as well for testing, I don't really care. If it makes a huge difference and it fails after 6 months then I'll know to buy a real one!

Has anyone tried the copy ones? (I don't want a pierburg and mafam).


tnx

Nick

[rossocorsa]

copy one may not be right from day one, I have two new copy ones that I was given (I sold some spares on ebay for a friend and he let me keep what i wanted from the box of stuff) but haven't tried them yet both mapco branded they look OK I might try one out at the weekend just to see