Horrendous fuel economy

[MATHOMAS32]

Hi I have a 1987 325i and recently the fuel economy has gone bananas. I used to get rouhly 50 miles from £10 of fuel now im getting about 25. I have replaced the air flow meter & the idle control valve and still no joy. Sometimes (not always) there is a strong smell of petrol when i start up but there does not seem to be any leaks. Also is there a standard setting (ie number of turns out) for the idle screw. Any help much appreciated cheers.
Mark

[Globulator]

Maybe check the mixture at an MOT station - if it's fine check brakes binding etc, otherwise proceed with engine fuelling.

Check spark plug colour - grey is OK, black and sooty means it's too rich.

Possibly the fuel pressure regulator - make sure the vacuum pipe is sound (i.e. fit a new one). Also check the tube from the filter to the injector rail for perishing.
If a lambda sensor is fitted then see if it works/replace.

[e30-320i]

when i had the same problem it turned out to be a perished fuel pipe from filter to fuel rail it was quite hard to spot as the fuel evaporates so fast the garage i took it too to sort out the overfueling missed it

[gcorky]

tried replacing ecu temp sensor....blue one?

[GDBN]

I'd do the blue temp sensor too. Just done mine and the fuel economy is much better. Old one was I presume 19 1/2 years old so was time for a new one.

G

[Rich25i]

Hi I have a 1987 325i

Thats the problem

Check all the fuel lines. i had a few tiny leaks that were very hard to spot. also the blue temp plug-mine ran much better with a mates one and better feul economy

Rich

[wildeian]

How much are them blue sensors??

[Simon13]

also check your throttle position switch. This makes for a strong smell of fuel on idle. My alpina is doing this

[MATHOMAS32]

Where is this blue sensor?

[Geoff]

Simon13 Posted: Mon Apr 10, 2006 9:08 pm Post subject:

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also check your throttle position switch. This makes for a strong smell of fuel on idle. My alpina is doing this

Yeah i was gona say the same thing. Changed mine and am now getting 28mpg on a run.

[gcorky]

its on the thermostat housing under front of inlet manifold

[MATHOMAS32]

Sorry to be thick guys but how do i adjust the throttle position switch?

[e30-320i]

it says how to do it in this guide somewhere mate
http://www.e30zone.co.uk/modules.php?na ... tbconv.htm