E30 Zone

happy owner of a 1987 325i cab. alrite lads heres the question? i get about 13-14mpg and about 28miles for 10pound on roads with very reasonable driving. im sure that even though petrol prices gone up i shudnt be getting that low consumption or maybe im wrong. what can affect fuel consumption?

im looking to do a proper service next weekend with the usual parts; plugs, oil/fuel/air filter,blue temp sensor. have already had a recent thermostat. just wondering what else do buy to improve my fuel consumption? do fuel lines affect consumption? and whats the best recommended oil to use.

Well fuel lines will affect fuel consumption if they are leaking. (Like mine did). But you the car will probably reek of fuel somewhere if this is the case.

Mine started to leak and I nearly gassed a rear seat pasenger!

nop no leaks what so ever on the fuel lines so will eliminate this out of possible reasons for poor consumption.

the parts you plan on fitting can't do any harm and hopefully may improve it. Have you had the car long? Has it always done poor mpg? Is there any chance some hooligan who had it before you has fitted a nasty ebay chip? (if it has always been doing similar figures)

28 miles for £10 and your a happy owner?

fuzzy wrote:28 miles for £10 and your a happy owner?

I think this is pretty much what I get! My car is running cold for most of my 4 odd mile journey on the way to/from work though.
How long are your journeys usually bmania?
At the moment i'm using our 4 door 325i and it runs perfectly as far as i'm aware. Economy is actually quite impressive on longer runs, I got 360 miles from a tank (it had just gone into the red when i filled up) on my trip to Croft a couple of weeks ago. Its just horrific when running cold or round town!
I use 5w/40 Comma fully synth. oil btw, aimed for track use really but should give pretty good economy and protection when running cold.

i get more than that from my cossie on hard driving thats surely really bad?

I can get 50 miles from a tenner in my Baur 325 if i drive sensibly and she warms up. But cold starts and never giving her a chance to warm up do have an effect

A 325i should give around 26mpg average, unless you're driving in central London traffic? Even my previous E34 535i would give between 22-30mpg.

Well if what I just read is to be believed in the US by 2020 all cars must acheve 35mpg, or they can't be sold.

In europe apparently plans are afoot to introduce a test for new cars to test the co2 per km which would be so strict no car currently on sale including the prius would pass.

Puts our e30's in the shade I think. I better think about a diesel conversion.

i mostly drive around town. it was not this bad since i had the car last year. is there a way to check if there is a chip on my car? also what is recommended to do to give me atleast over 20 mpg.

The worst I've ever got out of a 325 was 19 MPG, towing a large caravan into a strong headwind at illegal speeds.
Foot on the floor nearly all the time for three hours.
There is something very wrong with your car!
Where does the temp gauge sit on the dial?
How long does it take to get there?
What colour are the spark plugs?
What colour is the air filter?
Does it burn oil?
Compression test?

Just to let you know my story, filled up in Cornwall, drove to Hereford, A38,M5,M4 to chepstow then on to Monmouth then on to Hereford, done that at a steady 70mph mpg gauge reading above 30 or just below, turned round and folllowed same route home got down to Sedgemoor services on M5 with just over half a tank left was well impressed , then I came across a very heavy head wind and bang went the fuel economy used up half a tank in approx 70 miles what a bummer.

the temp guage sits in the middle, takes normal time to get there, after a cold start will take about 3 mins of idle to start moving from the cold zone, another 3-4 mins of driving and starts to go nearly to the middle of the temp dial. i used bosch spark plugs that were put in in august. The car runs very smooth though. will check the colour of the air filters and the tip of spark plugs later on in the day and get back to you. i think i may have used the wrong oil. 15x40. also as this is the first e30 ive owned, im still a newbie. so whats the best way to do a compression test?

btw my mpg dial started to play about a couple of months ago straight after the AA changed the crank sensor on mine which was attatched to the bell housing. it started working again for a day and then played up again. the mpg guage stays on 50 when the car is on idle and then as soon as i press the gas, even very slightly it goes all the way across to 0, so when im driving its always on 0. ecu maybe? could it be

bump

Try giving it a blast up a motorway to clear it out - big engines hate congested city driving.

yeah i might just have to do that. lol. aint given it a good bash for quite some time.

Stick some Redex or injector cleaner in the fuel tank before you do it, helps remove gummy deposits, etc.

no problem. before i stick some of that in the fuel tank, it gotta have a full tank rite? thanks

what is the norm tor a tank of petrol iv a 89 325 sport with 6branch, cat taken out and lamba sencer removedand put in a ecu for 325 with out cat, zone chip and gti filter alway service every 5000 miles i get round 260 to 270 miles to a tank, works out at 23miles per gallon have checked mpg a couple of times and it alway close to 23. i find if i drive my car on a bit i get a slightly better mpg if thats possible. is it a good idea to do a compression test?have changed the temp sencers

I'm currently crying about the fact my Sport (with a few mods) is only doing 16mpg on carefull driving!! BUT mine is seriously overfuelling and the timing is a bit off and needs a proper re-map!

You must have either lead feet or seriously out-of-tune M20s. All the E30s I've owned (2x 320i and 2x 325i) have always returned at least 25mpg average, and driving carefully I could squeeze 30mpg from the 325i and even an E34 535i on a motorway cruise. They've only ever dipped below 20mpg if I'm really caning them or stuck in heavy traffic, or once on a 325i where the fuel hoses split around the fuel filter, immediately noticeable by the odd handling created by petrol spraying over the back tyre and an accompanying stench of fuel.

what is the best way to do a compression test?

I do Manchester to Pompey on about 35 40 quid. Thats about 225 miles.

At average motorway speeds of 80 to 90 mph.

just a little 318 though.

I expect to fill my tank 3 or 4 times in 1200 miles back to England from the Balkans next week.

Damn good value IMO

u lot are rubbing ur petrol consumption in my face. lol. how can i make my consumption like yours that is the question

Cheapest way to do a compression test is buy a Gunson's pressure gauge from Halfords and have a go yourself!

http://www.halfords.com/webapp/wcs/stor ... &langId=-1

They're easy enough to do: whip out all spark plugs and jam the throttle wide open, screw the gauge into each cylinder's spark plug hole in turn and spin the engine for a few seconds on the starter motor until the gauge reading has settled, take a note of each cylinder's reading and compare them - on a healthy engine they should all be more or less equal.

If you have a low reading, to test if it's worn piston rings, squirt some oil into the cylinder and repeat the test: if compression goes up it's worn rings, otherwise it's worn valve seats/blown head gasket.

cheers mate youre a star. will do that 2moro and come back with results.

sorry last question. if i have to squirt some oil into the cylinder, do i do this through where the spark plug goes? im a newbie as you can tell

i also have a power boost valve fitted in the car, i presume this will make a difference on petrol consumption.

bmania wrote:i also have a power boost valve fitted in the car, i presume this will make a difference on petrol consumption.

And you're wondering why you get poor MPG???

lol. will remove it first thing tomorrow morning and see the difference. do i just replace it with a normal fuel control valve?

bmania wrote:what is the best way to do a compression test?

You need a compression tester,buy at Halfrauds or similar.Remove each plug in turn and place the comp.tester in it's place.Remove the H/T lead from the coil.Spin the engine over and record the result from each cylinder.Post up the result and we can give you an opinion....

I'd just add, you should also remove the Fuel Pump Relay (or fuse to it) while carrying out the compression test

FPR is the orange one in the middle of the relay block located under a black cover on the nearside inner wing (next to the radiator header tank).

Yes, if adding (engine) oil, apply it via the spark plug hole - you only need a teaspoon or two!

And wedge the throttle wide open!
You should remove the - connection from the coil, not the king pin. With the king pin disconnected, and the coil still being driven by the ECU, there's a good chance that the coil will arc over, and possibly spike the ECU.
Better way again, is to crank it from the diagnostic socket. That way, the ignition doesn't need to be on, so there won't be any sparks or fuel pressure.