W124 230E poor MPG

[chocolateobrian]

Or at least I hope it's poor. Last week I did 120 miles in my 1992 W124 230E auto. It took 27.25 litres to brim the tank today, and I've worked that out as pretty crap MPG even for an old girl like this, i.e. 20.01 MPG.

The car did do mainly short journeys admittedly but seems to warm up fine with the thermostat kicking in and keeping her between the 80deg mark and the next up (not numbered).

The MPG was better when I bought her and did 225 miles back up from Surrey to Scunthorpe but as the tank was filled with £20 here and £30 there I could only estimate at around 28-30 over about 367 miles over a few days.

I apologise if it's been done to death (bit like "what dump valve" or "which oil" threads on Scoobynet ) but I would appreciate to know if there is something not right with my car and if it is optimistic to expect a better return MPG wise?

She's got 142k miles on the clock and has the 4sp auto if it helps.

Cheers

Andy

 

[grober]

There are so many things that can affect MPG its almost impossible to give you an answer.
The obvious one is petrol leaks/ stolen . Second are increased rolling resistance- binding brakes, slipping transmission, under inflated tyres etc Third is a less than optimally tuned engine--ignition timing off, bad plugs, running rich due to incorrect fuel injection fault- blocked/collapsed catalytic convertor.
You just have to work your way through all these. However the most common fault is heavy right foot.

 

[markjay]

As grober said...

Also, is the car generally well-maintained? Things such as clogged air-filter could affect MPG. And, short journeys usually imply carbon build-up, a few tankfulls of Shell V-Power or BP Ultimate (or just a some Redex or Forte fuel treatment) might not be a bad idea. There is also this: http://www.ecotekplc.com/PowerBoost.htm but it's controversial and the jury is still out... or if you suspect the cat worth trying this: http://www.systemproducts.com/

But as grober said, it could be anything... so work your way slowly and check the basics first.

 

[chocolateobrian]

Ok thanks guys. The car could probably do with a check over so I'll change the plugs and air filter, and give her a change of oil. I assume a good semi synth 10w-40 is suitable for a 19 year old engine? Hopefully not a cat going bit can get the fueling checked at a indie.

Also when bought a couple weeks back I ran her on normal unleaded. But put V-power in today so see how that goes.

 

[219]

As with the others , the cause could be just about anything , but normal MPG for that car should be high 20's to low 30's .

 

[chocolateobrian]

Well I've not had chance or the money to service her yet but a new air/oil filter, an oil and plug change and the sorting of my knocking front suspension before MOT time will be top of my list when I'm paid this month.

Couple tanks of V-power saw my round town MPG be about 21.5 so an improvement there. Did a trip from Scunthorpe to Liverpool and back. Over 250 miles @ 70-75 on the motorway she did 32MPG which is much more like it.

I'm still kinda stumped to point the finger at one thing. As said I will try a service first and then look at getting the fueling checked. Suppose then it's looking at replacing the lambda sensor and cat?

Cheers

Andy

 

[Sp!ke]

Sounds to me like your fuel consumption is now roughly what it should be.

I used to average 26mpg in my 230.