M20b25 mpg?

[Hayden0]

What mpg are you guys getting? I'm averaging 16.5mpg? I've no idea if this is right or not? Just seems abit rubbish to me?

[popey7676]

I would expect between 270 and 330 miles to a tank, depending on how you drive it! So 16 is very low

[Morat]

I can easily see 18 on the OBC doing short hard runs - and 25 on the motorway.

[suchy]

14.9mpg on Tesco fuel
17.5mpg on Asda fuel
both combined

on a run 20mpg.

I have problems, sounds like you do too I'm afraid...

[suchy]

Never going to be high with an M20 engine though! But the sound...oh the sound

[Tom_Maverick]

well, I've been doing a bit of testing and I seem to be averaging about 22mpg! (and that's a mix between town and motorway, averaging 120 miles a week )

[Hayden0]

14.9mpg on Tesco fuel
17.5mpg on Asda fuel
both combined

on a run 20mpg.

I have problems, sounds like you do too I'm afraid...

What sort of problems do you have? I'm using shell fuel aswell.

Thanks for feed back guys!

[Jhonno]

What type of driving do you do?

Used to get 30+MPG on the daily mostly dual carriageway commute..

[suchy]

14.9mpg on Tesco fuel
17.5mpg on Asda fuel
both combined

on a run 20mpg.

I have problems, sounds like you do too I'm afraid...

What sort of problems do you have?

Overfuelling problems!!! Same as you!!

I have a thread in Tech you may wish to read;

http://www.e30zone.net/modules.php?name ... c&t=208867

I'm hoping to get a couple of days next week to have a play and check out all the helpfull advice offered

[Hayden0]

What type of driving do you do?

Used to get 30+MPG on the daily mostly dual carriageway commute..

Round town and b roads, I live in West Yorkshire so it's quite hilly. I drive slow most of time then I just open it up in second and let off now and again nothing stupid.

[Hayden0]

14.9mpg on Tesco fuel
17.5mpg on Asda fuel
both combined

on a run 20mpg.

I have problems, sounds like you do too I'm afraid...

What sort of problems do you have?

Overfuelling problems!!! Same as you!!

I have a thread in Tech you may wish to read;

http://www.e30zone.net/modules.php?name ... c&t=208867

I'm hoping to get a couple of days next week to have a play and check out all the helpfull advice offered

Oh cheers I'll take a look tonight on computer.
I have noticed when holding the rev around 2k I get a jerk from engine like kangarooing but if I give it more gas it stops? I've been thinking about a dodgy injector?

[suchy]

Mine is jerky low down on light throttle because of overfuelling. Can't use light throttle in 5th anything below 40mph without similar kangerooing feel- more revs cure it. Bogs down easily without heavy foot application. Loves to rev and burn the fuel though!

[Hayden0]

Just sounds like mine, have to do 80 on motorway so it doesn't get on my nerves lol. What are you thinking the problem is with yours? I'm a mechanic myself but I've learnt on the new cars as I'm only 20 so with the car being older than me I'm struggling to get my head round it haha

[suchy]

I'm really leaning toward the blue sender (engine temp) not comunicating with the ECU either at the plug conector or at the ECU end. It's very similar to driving with cold start (full choke for the oldies) on permanently. Also I think my throttle position switch (TPS) needs looking at and also throttle adjustment as light throttle really doesn't do anything, peddle needs to be at least half-way pressed to make a difference. If you read my thread you see I have other issues compounding the problem which may differ from your if standard, but the solution is the same! Very helpful info from Zoners on my thread so worth a read

[Grrrmachine]

Anything below 20mpg on these engines means there's something wrong, unless you drive with your foot to the floor at all times.

Have a read of this:

http://www.e30zone.net/e30zonewiki/inde ... ch_Running

[Jhonno]

OP.

I'd be looking at AFM and blue temp sensor to start.

[suchy]

Just sounds like mine, have to do 80 on motorway so it doesn't get on my nerves lol. What are you thinking the problem is with yours? I'm a mechanic myself but I've learnt on the new cars as I'm only 20 so with the car being older than me I'm struggling to get my head round it haha

Mine runs best at speed also and is actually more fuel efficient at 90 as it is at 60 (tested!!)

[popey7676]

I'd take the throttle body to pieces and give it a good clean out, that would probably cure the kangaroo effect.

[Tom_Maverick]

What type of driving do you do?

Used to get 30+MPG on the daily mostly dual carriageway commute..

if I just do the dual carriageway jaunt to work then I get similar to this.. it's the stop start 5mph into Brighton of a weekend that ruins those figures!

clearly some of the cars on here need attention!

[popey7676]

My old m20 high comp used to average 30 mpg and that was running at 189bhp.

[Hayden0]

Thanks for the help guys really appreciated. I've ordered a temp sensor while I'm at work, just short of £4.50 eliminates that sensor.

How do you find out if you have high comp engine or not?

[popey7676]

The earlier m20 2.5 pre facelift where high comp

[Morat]

Don't forget that tourings have a shorter diff so I'd expect them to return lower MPG overall.

[Hayden0]

So on an 89 I'm guessing mines not? I don't know the difference between pre-facelift and facelift? Sorry to be a pain

[HairyScreech]

Been done to death and a search would have given you about 4 threads at least.
a health m20 in good fettle should be between 25 and 30mpg combined.

[clipper]

Been done to death and a search would have given you about 4 threads at least.
a health m20 in good fettle should be between 25 and 30mpg combined.

I've gone from around 20 mpg to the average of about 27 - 28 on mixed driving.

Thing is it took a long time to get my car running "properly" and there wasn't one definite thing that made it change.

Firstly it appeared that someone had wound in the AFM mixture screw all the way to mask an air leak (this only showed up after H/G change), then I cleaned the injectors, changed the air filter, changed the fuel filter, found two minor leaks, adjusted the valve clearances a thousand times eventually changing the excentrics, discovered that my internal transfer pump was dead and out in a new one and a few more things too, all of which gradually improved the running of the car and at the same time improving consumption.

What I'm saying I suppose is what Brian always says, get the car to as close to tip top condition as you can and it'll run as BMW intended despite it's age!

[magpie]

you can service it till your blue in the face.

[HairyScreech]

Been done to death and a search would have given you about 4 threads at least.
a health m20 in good fettle should be between 25 and 30mpg combined.

I've gone from around 20 mpg to the average of about 27 - 28 on mixed driving.

Thing is it took a long time to get my car running "properly" and there wasn't one definite thing that made it change.

Firstly it appeared that someone had wound in the AFM mixture screw all the way to mask an air leak (this only showed up after H/G change), then I cleaned the injectors, changed the air filter, changed the fuel filter, found two minor leaks, adjusted the valve clearances a thousand times eventually changing the excentrics, discovered that my internal transfer pump was dead and out in a new one and a few more things too, all of which gradually improved the running of the car and at the same time improving consumption.

What I'm saying I suppose is what Brian always says, get the car to as close to tip top condition as you can and it'll run as BMW intended despite it's age!

this is always the case, of the ~ 7 m20 engines of several different displacements iv had near to have for any length of time all of them have been mid 20s to low 30s, the only reason i have seen for poor mpg is either: serious mechanical issues - air leaks, ring wear etc.
electrical issues or shady "tuning"/modification.

the benefit of the m50/52 in terms of mpg is its more advanced management, less pumping loss from a maf, it has much better fuel trim, better ignition and can advance the ignition right up to the knock threshold of the fuel in the car via the knock sensing system.
this means a bit more in terms of mpg.

[Speedtouch]

Thanks for the help guys really appreciated. I've ordered a temp sensor while I'm at work, just short of £4.50 eliminates that sensor.

How do you find out if you have high comp engine or not?

Look at the machined flat to the right of the inlet side engine mount, just above the block:sump interface. A high comp should be 25 6E, while later low comp is 25 6K.

You may need to use a wire brush and Jenolite rust remover and a bright torch to make out the markings.

Any M20 (B20 or B25) should return 25-26mpg average, if in a good state of tune - these were the official figures when new, and what I used to get out of my two L-Jet 320i and two 325i models, unless I caned them!

Poor economy may be caused by an aftermarket adjustable fuel pressure regulator (FPR) - ensure that you have the correct 3.5 bar regulator on the fuel rail.

[polsta]

if get in mine, do a 55 mile round trip to work, town-motorway-town, straight there, and straight back, driving with fuel in mind , i can do it twice on £20

but driving how you "want" to drive, is less

[hongkongfuey]

I did a run to rugby, i was getting 35 average motorway , round town im getting 20 mpg, mine is slightly modded

[spook]

And you dont drive like yer nan

[lukec88]

worked mine out at around 23mpg but i dont exactly drive it slowly and i like to have a little slide here and there too ;) its an 89 sport by the way if the diff is being considered in these readings?

[hongkongfuey]

The other thing i was going to say was, ive fitted an electric fan , ill probably be told that it has nothing to do with mpg, but it only comes on when its needed, doesnt put a strain on the water pump in any way. And in traffic you cant feel the effects unlike a viscous which can be heard and felt

[Kieran_n22]

The other thing i was going to say was, ive fitted an electric fan , ill probably be told that it has nothing to do with mpg, but it only comes on when its needed, doesnt put a strain on the water pump in any way. And in traffic you cant feel the effects unlike a viscous which can be heard and felt

How can you get rid of the viscous fan!?