1st proper run in my w124 - fuel consumption?

[mccrackenj]

Hi all

Well after over a month of ownership I've just had my 1st proper trip in the 300TE. A gentle 75 mile drive to a hotel (at a pretty steady 60mph, with a short stop in traffic of 5/6 mins) - followed by 2X gentle runs of 35 miles at 50-60 the next day, followed by a very steady 75 miles at 55-65 mph home today.

Average fuel consumption, calculated properly by brimming tank before and after - 26.0 mpg! Pretty disappointed by that. Previous to this trip, average consumption just pottering about on relatively short runs on suburban roads has been 15.5!

I don't expect much from a 3.0 6cyl of 1989 vintage and I can cope with high consumption given the relatively low mileage I do, but 15mpg around town and a best of 26 on a very gentle long run just isn't going to work.

Are these numbers completely out of line? Is this all I can expect?

[chazola]

Told you mpg was rubbish but yea, this sounds about right, I could only afford to run a 300E when I lived in the States. Is the engine in good tune? plugs, dizzy cap & rotor, air filter and fuel system etc in good order? I think it's r129sl who also has a 300TE, he should be able to tell you what his mpg figures are to compare.

[Johnboy Mac]

I'm presuming the car is a non CAT model, if so here's the offical figures.

City Cycle: 20.8 mpg
56 MPH: 31.3 mpg
75 MPH: 25.6 mpg


I ran a saloon which had hugh mileage on it and averaged about 22/23mpg mixed driving which I reckoned was reasonable for an old motor @ 1500kg, TE would be about 50kg more.

Edited by Johnboy Mac on Saturday 28th January 14:42

[Biglips]

That's about right. I get even less from my E36!!!

[bolide]

I've never know an 300TE to be anything other than thirsty. By contrast an E280 will do about 27 average and 31 mpg cruising at 75 mph

I drove a 320TE to Carlisle and back when my 33 mpg diesel was in the workshop. The 320TE gave 31 mpg average on that trip - but do the usual cold starts and stop-start in a six-cylinder petrol car and the mpg plummets

Nick Froome

[r129sl]

I get 23 to 24mpg out of my 320TE, a mix of a 30mile commute and long distance touring, generally driving far too fast (that engine begs to be thrashed).

[ClaphamGT3]

Sounds pretty good to me - what did you expect?

[mickyveloce]

26mpg on a run is as it should be .
It's a big heavy car with an old tech straight six ; mine varied between 18 and mid 20's .
I've subsequently had an E280 saloon which was tangibly better (27-29 average) and an E220 coupe which did nearly 40.
I'd swap my workhorse V70 for another nice condition TE anyday though

[mickyveloce]

26mpg on a run is as it should be .
It's a big heavy car with an old tech straight six ; mine varied between 18 and mid 20's .
I've subsequently had an E280 saloon which was tangibly better (27-29 average) and an E220 coupe which did nearly 40.
I'd swap my workhorse V70 for another nice condition TE anyday though

[mickyveloce]

26mpg on a run is as it should be .
It's a big heavy car with an old tech straight six ; mine varied between 18 and mid 20's .
I've subsequently had an E280 saloon which was tangibly better (27-29 average) and an E220 coupe which did nearly 40.
I'd swap my workhorse V70 for another nice condition TE anyday though

[mickyveloce]

26mpg on a run is as it should be .
It's a big heavy car with an old tech straight six ; mine varied between 18 and mid 20's .
I've subsequently had an E280 saloon which was tangibly better (27-29 average) and an E220 coupe which did nearly 40.
I'd swap my workhorse V70 for another nice condition TE anyday though

[mccrackenj]

Thanks for the responses chaps. It seems like the figures I'm getting are not wide of the mark then? The car certainly appears to be running perfectly so I assume nothing's amiss. It's had a new dizzy cap and rotor arm and I'll treat it to new plugs & air filter etc soon to see if it helps at all.

I expected fuel economy would be pretty poor, but I did expect more than 26.0 mpg on a long gentle drive, especially as I was making a special effort to drive as economically as possible. That's not too much of a problem though - it's the prospect of maybe 15mpg that I was getting overall before last week's trip that's a bit of a concern, especially as most of my journeys are in light traffic on suburban side-roads, i.e. without much waiting in queues or at lights etc - I really would have expected better than 15mpg there. That said, maybe a third of those journey are quite short (4 miles) so the car will be running cold for a fair proportion of the time.

Ah well, it's only money . . .

Edited by mccrackenj on Tuesday 24th April 12:43

[Johnboy Mac]

mccrackenj said:

Thanks for the responses chaps. It seems like the figures I'm getting are not wide of the mark then? The car certainly appears to be running perfectly so I assume nothing's amiss. It's had a new dizzy cap and rotor arm and I'll treat it to new plugs & air filter etc soon to see if it helps at all.

I expected fuel economy would be pretty poor, but I did expect more then 26.0 mpg on a long gentle drive, especially as I was making a special effort to drive as economically as possible. That's not too much of a problem though - it's the prospect of maybe 15mpg that I was getting overall before last week's trip that's a bit of a concern, especially as most of my journeys are in light traffic on suburban side-roads, i.e. without much waiting in queues or at lights etc - I really would have expected better than 15mpg there. That said, maybe a third of those journey are quite short (4 miles) so the car will be running cold for a fair proportion of the time.

Ah well, it's only money . . .

Dimiss the 15mpg, it's unimportant, actually it's a red herring. The only mpg that's relevant is the overall mpg.

[Gruber]

As others have said, that sounds about right.

My old w124 300E was doing circa 4000rpm at 75ish (if memory serves) which can't help. No idea why 4th ratio was so short.

[mccrackenj]

Johnboy Mac said:

mccrackenj said:

Thanks for the responses chaps. It seems like the figures I'm getting are not wide of the mark then? The car certainly appears to be running perfectly so I assume nothing's amiss. It's had a new dizzy cap and rotor arm and I'll treat it to new plugs & air filter etc soon to see if it helps at all.

I expected fuel economy would be pretty poor, but I did expect more then 26.0 mpg on a long gentle drive, especially as I was making a special effort to drive as economically as possible. That's not too much of a problem though - it's the prospect of maybe 15mpg that I was getting overall before last week's trip that's a bit of a concern, especially as most of my journeys are in light traffic on suburban side-roads, i.e. without much waiting in queues or at lights etc - I really would have expected better than 15mpg there. That said, maybe a third of those journey are quite short (4 miles) so the car will be running cold for a fair proportion of the time.

Ah well, it's only money . . .

Dimiss the 15mpg, it's unimportant, actually it's a red herring. The only mpg that's relevant is the overall mpg.

But that's the point though. The 15mpg is over a mix of usage that is much more representative of my overall usage than the longer run, so it suggests that my overall mpg will be much closer to 15mpg than anything 20+

Edited by mccrackenj on Tuesday 24th April 12:43

[r129sl]

To my everlasting surprise, I never do that well out of my Mercs when attempting an economy record. They seem to operate most efficiently not when pussyfooting around but when driven at 60 to 70%. The best I ever had out of my r129 was high speed cruising through Europe at 95mph all the way (28mpg). The best I got out of the 126 was hammering up the A1 then the A9 to Inverness and beyond, loaded to the gunwales with luggage, full bore overtakes all day long (24mpg). And the TE just dishes out 24mpg come what may.