318iS Consumption

[satty]

Hi,

recently bought a 1990/G reg 318iS, and am finding it quite juicy.
On a full tank (£47), it just about manged 230 miles!
Is this normal, because compared to my previous H-reg model, its quite bad. It has the 16" alpina's on it, this can't be the cause can it?

Also could there be a problem with the engine fuelling?

Cheers all

[E30Mark]

Depends on how you drive it, do you live in a hilly area? lots of short trips? etc

I managed 420miles to a tank once in my 318iS, used to average 37mpg on mixed driving

[Kos]

that is pretty poor for averidge driving

i always used to get 300+

[billgatese30]

i can get 300 on mixed driving in the 325 with £47 quid via mixed driving, i would have thought a 318is should be able to get more

[mattG]

i get 98mls to 30quid in my 325iT

[Kos]

the IS is probably the most economical e30 available

my 316i , filled it up the other day a long run no norfolk and back took up 250 miles, i'm now on 330 and still got 1/4 tank, so pretty much a good mix of all types of driving

[Pal318is]

230 miles is quite poor as already said...I once have 420 miles out of a full tank too...sensible motorway driving, with some town driving too.

Ain't got fuel leak anywhere have you??

Pal

[Dave_M3]

I managed to get 450 miles on round 40 quid on the way back from the UK. And I wasn't really economical, Welch Twisties on the way to get a 2:30AM boat

At the moment I cant really be sure as my Speedo is gone abit funny anond I've been doin a good few short trips over the last week or so and there on country roads but I still reckon I'm getting around 50 miles to a tenner anyway.

250 miles to £40 sounds very wrong, reminds me of my old 316

[Ajay325]

Satty, i've had my iS for a month and depending on how i drive, I can usually get roughly 300 miles from my full tank. I'm looking to replace my fuel filter soon as it should improve my MPG, maybe you should try that too, it is a bit tricky as I believe the filter is located near the tank. If that doesn't work, you have a very heavy foot.

HTH
Ajay

[gra325i]

"If that doesn't work, you have a very heavy foot." who hasn't in an iS? Personaly, i can't help but drive the wifes iS hard (it's just so revvy compared with my 2.5) but i get about 250/60 miles, mixed driving

[anisotropy]

Always get over 300 to a tank even on lots of short trips. Fuel filter probably wouldn't make that much difference, if there's a fuel leak you can usually smell it, BTW on UK ISs fuel filter is in engine bay under PS resevoir, easy to get at.

[Ajay325]

Always get over 300 to a tank even on lots of short trips. Fuel filter probably wouldn't make that much difference, if there's a fuel leak you can usually smell it, BTW on UK ISs fuel filter is in engine bay under PS resevoir, easy to get at.

learn something new everyday! nice one mate i'll be changing that soon.

[darkchild]

Satty, i've had my iS for a month and depending on how i drive, I can usually get roughly 300 miles from my full tank. I'm looking to replace my fuel filter soon as it should improve my MPG, maybe you should try that too, it is a bit tricky as I believe the filter is located near the tank. If that doesn't work, you have a very heavy foot.

HTH
Ajay

Could be any number of things. Knackered air filter, faulty oxygen sensor causing rich running, coolant temperture sensor, incorrectly adjusted air flow meter, throttle position switch bodged by previous owner, leaky fuel tank....

[choppa7]

Check the spark plugs to see if its running rich, then jack it up and have a look at the petrol tank to check for leaks, I think the filler neck at the top seems to be a common place for holes to appear

[Frenchy]

Mine gets 30+ and even better on a run....Check for leaks!

[zimm_zimmer]

im getting like 310 miles outta a tank from my 325i sport lol

[Ajay325]

im getting like 310 miles outta a tank from my 325i sport lol

yeh mate, but i'm pretty sure your tank is larger than the iS, ours fills up in around £45

[darkchild]

im getting like 310 miles outta a tank from my 325i sport lol

yeh mate, but i'm pretty sure your tank is larger than the iS, ours fills up in around £45

IIRC the 318is tank is 55 litres and the Sport tank is 63 litres.

[cheesebox]

Ajay[/quote]

Could be any number of things. Knackered air filter, faulty oxygen sensor causing rich running, coolant temperture sensor, incorrectly adjusted air flow meter, throttle position switch bodged by previous owner, leaky fuel tank....[/quote]

Just reading this thread now as I can't get the same mpg out of my current iS as I did from my previous one (300 vs 350 for same type of driving and journeys), and would like to fix this!

Can anyone advise please:

- Where's the coolant temp sensor and can it be tested?
- How do you check the AFM is correctly adjusted?
- How can I check the throttle position switch?

Has anyone succesfully improved the fuel economy of a 318is?

Cheers

[Alfa_Delta]

I'd start by servicing the car and checking everything. Something as simple as dragging brakes can cause a drop if MPG.

My E30 318iS used to be a bit jeckle and hyde when it came to fuel consumption. If you were really gently with it, didn't rev it and didn't use full throttle it was excellent on fuel. If youkept it in the "16v zone" it would drink like Oliver Reid!

Your fuel consumption does sound very bad though. My iS would do 350+ miles on a full tank and was very very good on a long motorway run (as long as you were the legal side of the tonne).

[jimthejunior]

Interesting reading. My 316i touring is lucky to pull 200 miles from a full tank. To says its killing me is an understatement. Although i have a heavy right foot, most of it is crusing on the motorway trying to keep it at about 20mpg. Gonna change the diff soon though as that should help a bit.

[tomtomtom]

mine used to be economical but its thirsty as at the moment, its leaking air in somewhere and i havent got round to fixing it but checking the CO at a garage the other day it wasnt burning half the fuel it was chucking in. i'd check your emissions and they'll prob tell a tale, if its putting loads of juice through it might be the ecu compensating for an air leak. saying that i drive it like a cooont, but went on a long trip to wales for new years and it went from brum to aberystwyth and back again with me, my mate and two dirty swedish birds in and only used 3/4's of a tank which i thought was quite good. better than my mates 57 reg 1.4 corsa sxi actually!

[cheesebox]

To start I'm going to fit a standard air box - the previous owner fitted a K&N cone filter. That may help.

I could do with knowing how to check the other things though, ie coolant temp sensor, AFM and TPS. Can anyone advise?

[Cook318IS]

i refitted my standard airboxthe other day on my iS after having a kn cone filter. just one word of warning - dont put a halfords air filter in, but a bmw one in. the halfords one doesn't sit properly in the air box, the orange gasket round the top of the filter is too big but it will still fit if you force it. you even get more performance outta the bmw filter than the halfords one too!

[cheesebox]

i refitted my standard airboxthe other day on my iS after having a kn cone filter. just one word of warning - dont put a halfords air filter in, but a bmw one in. the halfords one doesn't sit properly in the air box, the orange gasket round the top of the filter is too big but it will still fit if you force it. you even get more performance outta the bmw filter than the halfords one too!

Good tip, cheers. I don't have the threaded studs to re-fit the airbox - they were discarded by the previous owner, so I need to find some. I think I'll just "modify" some bolts.

[Cook318IS]

yea i put the kn filter on myself so i kept all the bits i took off in the box of the induction kit.

[jonboye30]

gd tips there, i also get bout 230miles 2 a full tank in my is, will need 2 try some o these sudjestions. Satty if u find out ur problem with it let us know and il try it on mine

[Dr Firefly]

My new answer for everything to do with idling, fuel economy etc is... take it to Ant. I'd spent 2 years and about £300 trying to get mine running better and not gobbling fuel. 2 hours and £100 with Ant and his little laptop - sorted. (Involved changing every component in the intake system except ICV and throttle body, because they'd all been bodged trying to get it fixed on the cheap by previous owners)

[Cook318IS]

i also get bout 230miles 2 a full tank in my is,

mines abit like that too but my exhaust has a small blow (but its still under warrenty if i can find the receipt for it!)and i think the spark plugs are due a change on the next service.