Gas mileage sucks, Need tips to lean this 535 out a bit.

[Jeff in MN]

Around town I have been driving like and old lady and only getting 15.5 mpg with some freeway driving included. Everything seems to be working ok, so I want to start tinkering.
Running 89 octane
Running EAT chip

Any ideas would be appreciated.

Thanks,
Jeff in Minnesota.
(Not ready for winter)

[e34m30SF]

That's about average. M30s are not known for great mileage. Right now I'm getting 8.6 b/c of the darn San Francisco hills.

[mamilapon]

When was the last time you changed your O2 sensor?

[Omega]

That's about average. M30s are not known for great mileage. Right now I'm getting 8.6 b/c of the darn San Francisco hills.

8.6? That's MPG????

Damn......:(

[Ferret]

When was the last time you changed your O2 sensor?

Yeah with highway mixed in you should at least see 17-19 out of it :(

[Ferret]

8.6? That's MPG????

Damn......:(

GPM!

If I tried I used to be able to get ~9 MPG out of my old M50 525i... though it was quite hard to keep it that low, coasting would make it shoot up to 13 :D

[Dave M]

GPM!

If I tried I used to be able to get ~9 MPG out of my old M50 525i... though it was quite hard to keep it that low, coasting would make it shoot up to 13 :D

Wow. I'm pissed if I get > 10 L / 100km (low to mid 20s MPG), over the long-term in mixed driving. I do a lot of coasting ;)

Road trips see b/w 29-32 MPG.

Dave

[e34.535i.sport]

Have you changed the fuel filter? WHen i done mine a couple of months back i found it hadn't been changed since 1993! Easy to do and car felt better for it. Think i done a write up on it... do a search...

[Jeff in MN]

When was the last time you changed your O2 sensor?

At the begining of the summer I put the multimeter on it and it was fluctuating as it should and reading about .445 volts (Average)

[J.DeFeo]

What kind of gas are you using? I found that I got much worse gas mileage using no-name gas, especially with the EAT chip. I started using Shell and my mileage went back up to normal. No change in driving habits, 80% highway, 20% normal roads and I get about 24.5MPG combined. I was getting 22MMPG with the cheap crappy gas.

[Jeff in MN]

:)
Have you changed the fuel filter? WHen i done mine a couple of months back i found it hadn't been changed since 1993! Easy to do and car felt better for it. Think i done a write up on it... do a search...

[Jeff N.]

Jeff - I don't think you'll get much better than what you're already getting. Check your tune but what you report is pretty typical for mixed driving with the bulk of it in the city.

Best thing you can do is softpedal the car.

Sucks (gas) huh?

[Sam-Son]

I can't believe the 3.5 sucks down so much gas. My 525 with a TMS chip running on 93 gets 20-21 city and 35 highway. And I drive everywhere like my hair's on fire

[Torque]

Sounds about right.

Surely though, you didn't buy a 535 for economy ... I was well aware what I was getting into, selling my 30mpg car to own a 535. :D

edit: why are you only running 89 on a EAT chip?

[Omega]

GPM!
If I tried I used to be able to get ~9 MPG out of my old M50 525i... though it was quite hard to keep it that low, coasting would make it shoot up to 13 :D


9 MPG is very impressive! You are a God. :D My M52 523 usually hovers around 19-22 MPG and for that matter so did the M50 525. Driven in real anger I got the 525 down to 12 MPG a few times.



What kind of gas are you using? I found that I got much worse gas mileage using no-name gas, especially with the EAT chip. I started using Shell and my mileage went back up to normal. No change in driving habits, 80% highway, 20% normal roads and I get about 24.5MPG combined. I was getting 22MMPG with the cheap crappy gas.


A good idea, but you have to do a cost analysis of the gas price to see if it really is beneficial. In the UK premium gas like Shell is very very (very) expensive, compared to the cheap supermarket gas; which is just expensive.... A nominal increase in mileage (cf 2mpg) might not be worth the difference in the pump price of the gas!

[repenttokyo]

in canada, we don't really have premium gas and cheap gas,it's just sorted by octane.

[wjbell]

I just recently replaced my cap, rotor, wires, plugs, air and fuel filters and did an oil change. O2 was replaced about 6 months ago. I took it on a 3 hour round trip freeway drive and the OBC showed 21 MPG. City I probably get from 13-18.

[ThoreauHD]

Maybe I missed something, but doesn't the EAT chip require 91 or better octane. I know octane is lesser the older the car, but doesn't the EAT/Conforti chip change that timing? I use 93 octane shell in my V8. I'm at 26 mpg. It's not great but it's better than it was before, which I think was around 19-20 mpg. If that octane is proper and the spark plugs are new/02 sensors are functioning.. that does make one sad.

[Torque]

Maybe I missed something, but doesn't the EAT chip require 91 or better octane. I know octane is lesser the older the car, but doesn't the EAT/Conforti chip change that timing? I use 93 octane shell in my V8. I'm at 26 mpg. It's not great but it's better than it was before, which I think was around 19-20 mpg. If that octane is proper and the spark plugs are new/02 sensors are functioning.. that does make one sad.Is that 26mpg according to OBC or actual?

If it's actual, how do you do it. Do you not accelerate ... ever?

[bahnstormer]

city i get 12s and highway i get low 20s on my 91 with a 3.64 and eat

check tire pressure and go on a diet? =]

[Alexlind123]

I get 25.6 on the highway/curvy country roads when following someone driving a mustang 5.0 with a lead foot. I get 20 with my normal city/highway/country commute.

[632 Regal]

thats what im saying, i only get 20-23. never was better than that.


Is that 26mpg according to OBC or actual?

If it's actual, how do you do it. Do you not accelerate ... ever?

[Jeff in MN]

Maybe I missed something, but doesn't the EAT chip require 91 or better octane. I know octane is lesser the older the car, but doesn't the EAT/Conforti chip change that timing? I use 93 octane shell in my V8. I'm at 26 mpg. It's not great but it's better than it was before, which I think was around 19-20 mpg. If that octane is proper and the spark plugs are new/02 sensors are functioning.. that does make one sad.

Hopefully higher mpg will offset fuel costs. either way I'll report back the results.

[Jeff N.]

Changing your octane won't help your mileage. If you're not pinging with 89, I wouldn't up the octane.

You may need to run 91+ in hot weather.

Do you have ethanol gas blends in Minnesota? I seem to recall that lowering the effective mileage.

[Jeff in MN]

Sounds about right.

Surely though, you didn't buy a 535 for economy ... I was well aware what I was getting into, selling my 30mpg car to own a 535. :D

edit: why are you only running 89 on a EAT chip?

the mileage I get on the e28 535, but I keep forgetting stick vs. auto cuts into the economy. Good point on the 89, as mentioned below I am going to bump up to 91+ and see what happens.

[Jeff in MN]

Around town I have been driving like and old lady and only getting 15.5 mpg with some freeway driving included. Everything seems to be working ok, so I want to start tinkering.
Running 89 octane
Running EAT chip

Any ideas would be appreciated.

Thanks,
Jeff in Minnesota.
(Not ready for winter)

Stay warm.

[Paul in NZ]

my trip to work is 40 km.By far the majority is on flat highway,but every few kms there is a traffic light.( 9 sets) so you are cruisin at 60 mph then you have to stop and accellerate back up to 60.As i get near home i have to climb a steep hill.My average is 19-20 mpg and that imperial gallons.My car has no o2 sensor(never has) and i think i can get better mileage out of cars than the average joe....The fuel consumption is my single biggest beef about the 535.

[rob101]

might be worth pointing out americans and englishman have different sized gallons
1 UK Imperial Gallon = 4.55 litres
1 US Liquid Gallon = 3.79 litres
about 20% difference
so your MPG's will be diff also

[leicesterboy15]

I get about 15 (UK) mpg in heavy traffic in my 535i which has a superships chip. The consumption on my 540i is better than the 535i in town and on a run. Since I have owned the car (nearly 4 years) it has been around the same and it runs sweet so I have just learned to accept it!

Over here I believe our standard fuel is 95 octane (96.9 pence per litre) and the super stuff is 98 octane (about 103 pence per litre).

[Derek A.]

my trip to work is 40 km.By far the majority is on flat highway,but every few kms there is a traffic light.( 9 sets) so you are cruisin at 60 mph then you have to stop and accellerate back up to 60.As i get near home i have to climb a steep hill.My average is 19-20 mpg and that imperial gallons.My car has no o2 sensor(never has) and i think i can get better mileage out of cars than the average joe....The fuel consumption is my single biggest beef about the 535.

What fuel injection system are you running - that doesn't have an o2 sensor ?

[Ferret]

I get about 15 (UK) mpg in heavy traffic in my 535i which has a superships chip. The consumption on my 540i is better than the 535i in town and on a run. Since I have owned the car (nearly 4 years) it has been around the same and it runs sweet so I have just learned to accept it!

Over here I believe our standard fuel is 95 octane (96.9 pence per litre) and the super stuff is 98 octane (about 103 pence per litre).

Iirc the US has a different method of measuring octane - hence their figures are always about 5 lowers than ours for the same fuel...

[Macv]

I changed my plugs, coil packs, and coil boots and saw +3 mpg increase. And it's stuck at that level ever since.

Id say, plugs, coil packs, boots, injectors ($$), eat chip, new job

[ILoveMPower]

Aren't you supposed to use 91+ octane only with the EAT chip..?

My chip is stock and I still run 93 all the time

[Robin-535im]

Yeah with highway mixed in you should at least see 17-19 out of it :(
I got 18 pretty steady in mixed driving until rebuilding the head, now I get 20 mixed with a peak of 23 or so at 100% highway driving. 8 sounds pretty low! IIRC, Martin in Sacramento put on an adjustable O2 sensor and is able to get much better MPG by setting the Air/Fuel ratio at a different operating point.

[e34.535i.sport]

My fuel economy according to the OBC averages around 18-19mpg around town if i drive like an old lady. I'm not sure this is totally accurate however... If i get stuck in heavy traffic its about 13mpg.

On a long motorway run the OBC told me i averaged 30mpg but when i worked it out it was 27(point something)mpg, but i was still pleased! That was a while back and i was trying hard, my fuel economy has took a turn for the worse lately.

[Tiger]

EAT Chip has a mandatory 93 octane fuel requirement... Have you tried that to see if fuel mileage increase?

[ILoveMPower]

EAT Chip has a mandatory 93 octane fuel requirement... Have you tried that to see if fuel mileage increase?

Thank you, I could've sworn it called for high octane

[John B.]

EAT Chip has a mandatory 93 octane fuel requirement... Have you tried that to see if fuel mileage increase?


I run an Eat chip in my 90 535i & have no problems running 91 octane. In fact I notice no difference at all between the 91 & 93 octane gas. As far as fuel mileage goes I've never seen less then 18mpg (U.S.) around town & on highway trips I average 24-25mpg cruising at 80mph. Before the Eat chip I got as high as 27 mpg on one trip & this is real world mileage not by the OBC.

[BFEINZIMER]

12-13

it sucks

[Robin-535im]

My fuel economy according to the OBC averages around 18-19mpg around town if i drive like an old lady. I'm not sure this is totally accurate however... If i get stuck in heavy traffic its about 13mpg.
18 is about the lowest I can get, and it's not for lack of trying... :)

[Jeff N.]

18 is about the lowest I can get, and it's not for lack of trying... :)

I think you better check that gas pedal - sounds like you have the floor mat jammed underneath it.

Dude - how the hell are you getting 18 MPG with 3.91 rear end and a lead foot? Something's not right! Did they get rid of all the stop lights in NM?

[Paul in NZ]

What fuel injection system are you running - that doesn't have an o2 sensor ?

std....when my car was sold new here we were still running leaded petrol.so no cats and no o2 sensor..

[Robin-535im]

I think you better check that gas pedal - sounds like you have the floor mat jammed underneath it.

Dude - how the hell are you getting 18 MPG with 3.91 rear end and a lead foot? Something's not right! Did they get rid of all the stop lights in NM?

Didn't Bill R post about some group that determined if you drove at 90% gas pedal you got the best economy?

Maybe the "1" in the OBC is stuck and it's really 8 MPG :)

Last I checked the OBC reading matched the manual math of odometer/gas receipt. Then again, we have less air up here, so maybe you guys flush with all that O2 get to burn more gas... we just suck vacuum up here.

Drove to Flagstaff and back last weekend, 350 miles each way, ~23 MPG at [----edited for legal reasons ---] "the exact speed limit and no higher"

[Paul in NZ]

the 535 certainly has a sweet spot way higher than our measly 100 kph speed limit

[rob101]

the 535 certainly has a sweet spot way higher than our measly 100 kph speed limit
525i m50 wants to cruise at about 120 kph. can't see the 535i being less than that.
http://www.e34.de/e34/unterhalt.htm
in the column entitled "Verbrauch" you can see the fuel economy highway/city for the various models in L/100kms
it says in the notes that the highway values its measured at a constant 120 kph speed.

[NovceGuru]

My 1993 525i (m50tu) gets 27mpg cruising at about 75 :( stupid 4.10 rear end automatic #@*&(*#@&$@#

[whiskychaser]

My 1993 525i (m50tu) gets 27mpg cruising at about 75 :( stupid 4.10 rear end automatic #@*&(*#@&$@#
I get about 30 UKmpg at 75. No cat. Not that excellium stuff (that's supposed to give you 30 miles more per tank or your money back)either

[Torque]

My 1993 525i (m50tu) gets 27mpg cruising at about 75 :( stupid 4.10 rear end automatic #@*&(*#@&$@#27 is exceptional.

[e34.535i.sport]

If you are doing long motorway journeys try this to up your fuel economy - Cruise at 70mph and then accelerate to 80mph (ish) and then let off the accelertor until you slow to 70mph again, then accelerate to 80 again and let off the accelerator again... Repeat... I don't know if this just tricks the OBC somehow but i've got some very good mileage figures doing this!

[e34.535i.sport]

Also, when your exit is coming up i normally cruise for the last half mile to and down the slip road, this helps!

I just got 22.2mpg on my way home from a relatives house about 6mile away (city driving)... quite impressed!

[Torque]

If you are doing long motorway journeys try this to up your fuel economy - Cruise at 70mph and then accelerate to 80mph (ish) and then let off the accelertor until you slow to 70mph again, then accelerate to 80 again and let off the accelerator again... Repeat... I don't know if this just tricks the OBC somehow but i've got some very good mileage figures doing this!It gives a good mpg according to the mpg ... but thats really wasting lots of gas.

It's because the OBC doesn't know **** other than the inputs it gets ... and when you let off the gas pedal it gets 99.9mpg as your current consumption.

[e34.535i.sport]

You're probably right, the OBC isn't fool proof! However, i done some math on a long run and got almost 28 (real life)mpg with this method out of a 3.5L - not bad!

[Torque]

I get 28 according to my obc with the max possible coefficient factor entered into it ... still about 8mpg high.

[MaloventEvil]

@ OP: why are you using 89 gas w/eat chip? doesn't it require 91 octane?

[Jehu]

I feel pretty good ,thanks. With the weather now getting much colder i saw my highway mileage jump to a pretty steady 25 average with 27 on the flats. Is it the Royal Purple? the Lubro Moly Ceratec? The Denso iridiums? the Clean Air Filter? The 93 octane? or is it just exactly perfect?

http://img84.imageshack.us/img84/5228/crane013yv8.jpg