E300 td mpg - help!!

[Dieselman]

I'm going to try changing the gearbox oil next month (it jerks a bit between 3rd and 2nd gear on the downshift anyway) and also have the badly repaired serpentine belt tensioning pulley fixed (it squeals a bit when cold). I don't see how either of these could improve the consumption but I'll let you know if it does!

The gearbox shift quality could be as a result of a tired MAF, this would also affect consumption.

Your consumption doesn't actually sound bad and is hugely influenced by driving style.

I only got 24mpg after the car hadn't been used for two months and only doing local journeys.
After two tanks life was back to normal 32~33.

 

[ticex]

The gearbox shift quality could be as a result of a tired MAF, this would also affect consumption.

Interesting point about the MAF. I remember on a Golf TDI I had a while back the car was flat as a pancake when the MAF went but perhaps the Mercs react differently. However, the gearshifts are perfect for all other shift combinations - it's just the one from 3rd to 2nd when driving around down that jerks the car. Could this be the MAF? I think I'll get the oil changed anyway and if it doesn't get better start looking at the MAF. Does anybody have an idea of how much the MAF costs on the E300 turbo-diesel?

 

[Shude]

Does anybody have an idea of how much the MAF costs on the E300 turbo-diesel?

If you get it from the stealership you're looking at about £250ish. Other solutions are available, that's pretty much the easiest but most expensive way of doing it.

 

[DrNick]

Changed the MAF on mine recently. It only affected the higher end of the rev range in that it pulls like a train past 3500rpm now, whereas before it pulled like an overloaded train!
Consumption was not affected in any measureable way with the sort of driving I do (motorway on cruise control). My MAF problem was identified by measuring the output and comparing to Dieselmans graph (posted months ago). Mine read very low. I'm not convinced the MAF has much to do in most driving conditions for this diesel. Only when you welly it.

Consumption on mine is about 30-31, which is lower than it was a year ago when it was 33-34. Doesn't seem like much difference but when you are used to getting consistent numbers to within 1 mpg, a drop of 2 or 3 mpg is significant of something changing. Nothing seems to make much difference (AC, tyre pressures- within reason) although changing the air filter helped for a couple of tanks..

No idea what caused the drop - seemed to happen when the glowplugs were changed, so I'm wondering if something hasn't been done up correctly on the inlet side especially as the manifold was loose at one point!

 

[Dieselman]

Does anybody have an idea of how much the MAF costs on the E300 turbo-diesel?

The genuine Bosch Maf is about £200 but use the Pierburg one for the 320 CDi and it's about £44.

 

[230K]

Hi

Picture of 300 Turbodiesel with half a tank.

230K

 

[Dieselman]

Ah, a safety shot this time, not moving.

I saw 400 mls to 1/2 tank once when coming home from Fort William..Happy..You bet.

 

[230K]

Hi

Checking back through my little blue book best ever was actually 577miles on 67.13litres which worked out at 39.07mpg, if you have got 80 litres into the car then 600+ miles to your tank should be easily achievable. When i ran out in France 72.75litres filled it to the brim.

How often are fuel pumps on the forecourt tested or calibrated, i sometime wonder are they really that accurate.

What speed would you have been travelling at to get 400 to half a tank?

230K

 

[Dieselman]

Hi

Checking back through my little blue book best ever was actually 577miles on 67.13litres which worked out at 39.07mpg, if you have got 80 litres into the car then 600+ miles to your tank should be easily achievable. When i ran out in France 72.75litres filled it to the brim.

How often are fuel pumps on the forecourt tested or calibrated, i sometime wonder are they really that accurate.

What speed would you have been travelling at to get 400 to half a tank?

230K

Best ever is 655 miles. 74.7L, 39.9 mpg.
Best ever consumption is 40.04 mpg.

 

[C240Sport97]

average is 21 mpg
town is 15 mpg
motorway at 90mph is 25/26 mpg

moral of the story? faster is better for the environment and my wallet!!

 

[fwb44]

We had the MAF sensor changed on our '98 E300 TD estate 220,000 miler last week and saw the fuel consumption improve by 25% immediately, back to around 400 miles per tank. Only symptom of the problem was high fuel consumption - no loss of performance, no black smoke, nothing. £190 for the part tho'! And the 3rd time it's had to be changed in 140K miles ...

 

[ticex]

Hi there,

Just thought I'd let you all know, further to my rather poor fuel consumption mentioned before (~28MPG on the motorway) I took my MAF out tonight and gave it a clean with brake cleaner. I just sprayed it on the wire you can see through the hole at the bottom, on the litle fork shaped contacts on the back of it and on the connector terminals at the top for good measure.

Well, what a pleasant surprise....the fuel consumption has now jumped up to 36mpg instantly with exactly the same driving and my sloppy 3rd to 2nd gear change has become a whole lot better too! I think the brake cleaner hasn't completely fixed the problem so I'm going to fit a new MAF on Monday. I think I'll go with the Pierburg CDI MAF's which I've been told work perfectly well with the 300TD and they cost about £50 instead of over £100 for the Bosch one. I know the Pierburg MAF is much better from experience as I fitted this identical Merc one into my old Golf TDI and it lasted for all the 40k miles I had the car for without a fault whereas the Bosch one only lasted 15k miles!

I'll let you all know if the new MAF makes any further improvements.

Greetings,
Michael

 

[Branko]

I changed just the MAF (the bit that screws into the housing) about 6 months ago and got a pierburg (?) unit from Eurocarparts (less than £50). I do a lot of in town driving and find economy quite bad 22 to 25 mpg. The best I have ever achieved on a tank full is 420 miles which is no more than 30 mpg. I have a green cotton air filter and always use Millers diesel additive. All 6 glow plugs were changed in November 2004. Tyres are 235/45s and are at 30 psi front and 35 psi at the back. Mileage is 104,500 on my E300TD.

Any ideas?

 

[Paul64]

I run a '92 500E down here in France and recently had a business trip from Nice to the East Coast of Italy, just over 1600km round trip.
I have to admit, we didn't hang around once in Italy and when I got back, the average for the 3 fill-ups was just over 22mpg...
That's cruising often between 100 and 120 for most of the journey with only a couple of slow-downs for roadwork contra-flows.
I am amazed how poor the 300 Diesels seem to be on fuel -I seem to remember reading the 320CDi's are a whole lot better.
Perhaps they should have kept on with the W124's a bit longer...?
Is the 300 turbodiesel engine the same as the W124's straight 6??