HELP:E34 High Fuel Consumption

[wan520i]

Dear guys, Need your inputs & suggestions to improve my car's fuel consumption, currently is running RM 0.33 per km, I filled up RM50.00 of Shell unleaded petrol lasted for 150km only, small city drive, hardly got traffic jammed, and not much waitng/idling time. Car: E34-M50 vanos, 2.5, automatic trans-5 speed. (converted from 520). Original exhaust system with cat. convertor. Tire: 235/45/17 all round. Full time luggage: 2 pcs 10 inch woofer in sealed box (about 35kg). Parts: -Already replaced fuel regulator few months back, -just clean my fuel injectors, - checked CO % = 0.00.- Spark plugs: bosch platinum changed last year.- Original paper air filter.- Fuel filter change annually.- O2 sensor from half-cut during engine conversion.- Rear axle: 3.91 non-LSD.- Engine oil: mobil semi-syn 10w/40. Your inputs please....THANKS! :rock:

 

[june_yap]

me also facing about same problem, some said install NGV system....

 

[anaksarawak]

NGV may be the soution... But the followings are my personal advice

1. Change to a new O2 sensor as your may be also faulty (2 units)
2. Change to original spark plugs from BMW (Auto Bavaria or Sapura Auto)
3. Service your air-con, espcially your compressor
4. Check your alternator as if its old it cause drag
5. Cluch fan.. replace with electric fan
6. Change to 16" alloy rims with standard tyres
7. Your gearbox may be on the correct gear (slow change)


Good luck bro... Anyway, I always support NGV

 

[leforte]

it would help if you can provide us the "normal" fuel consumption prior to the 0.33cents/km consumption you are currently experiencing.

a before and after fuel economy status as well as a timeline for modification/changes done to the car may very well help us narrow things down.

 

[june_yap]

NGV may be the soution... But the followings are my personal advice

1. Change to a new O2 sensor as your may be also faulty (2 units)
2. Change to original spark plugs from BMW (Auto Bavaria or Sapura Auto)
3. Service your air-con, espcially your compressor
4. Check your alternator as if its old it cause drag
5. Cluch fan.. replace with electric fan
6. Change to 16" alloy rims with standard tyres
7. Your gearbox may be on the correct gear (slow change)


Good luck bro... Anyway, I always support NGV

my previous e30 m20b20 did the electric fan conversion, engine feels lighter, but have to use mercedes electric fan and did a bit of modification.

 

[ehoe]

me also facing about same problem, some said install NGV system....

Err June yr car a little different ya. Don't forget its got a SuperChip installed so consumption will definately be a little higher compared to stock ya. You want better FC, you can consider changing rear diff ratio to higher gear ratio, that should improve FC a bit and you get a higher top speed. But of course then your pickup not as good lor.

 

[keray]

Try checking your alternator.

 

[june_yap]

Err June yr car a little different ya. Don't forget its got a SuperChip installed so consumption will definately be a little higher compared to stock ya. You want better FC, you can consider changing rear diff ratio to higher gear ratio, that should improve FC a bit and you get a higher top speed. But of course then your pickup not as good lor.

oic... no wonder i went 180km/h only... :listen:

 

[wan520i]

me also facing about same problem, some said install NGV system....

june, NGV system impossible for me lah, cause no NGV station here...Thanks.

NGV may be the soution... But the followings are my personal advice

1. Change to a new O2 sensor as your may be also faulty (2 units)
2. Change to original spark plugs from BMW (Auto Bavaria or Sapura Auto)
3. Service your air-con, espcially your compressor
4. Check your alternator as if its old it cause drag
5. Cluch fan.. replace with electric fan
6. Change to 16" alloy rims with standard tyres
7. Your gearbox may be on the correct gear (slow change)

Good luck bro... Anyway, I always support NGV

Geoffrey, thanks for your tips, my car has 1 unit of O2 sensor only & i will check on it. also will check on a/c compressor & alternator. I bought bosch platinum spark plugs from bavarian-auto, believe they are original & suit M50 engine. Can you pls tell me more about your tip#7. Thanks.

it would help if you can provide us the "normal" fuel consumption prior to the 0.33cents/km consumption you are currently experiencing.

a before and after fuel economy status as well as a timeline for modification/changes done to the car may very well help us narrow things down.

lefrote, sorry I can't remember when this "makan minyak" happen, but i guess it happen ever since my engine conversion..., i tot is was normal for 2.5 liter, but after knowing you guys are running about average of 0.25 cents/km, i realized that my car is not normal...pls help. Thanks.

Try checking your alternator.

keray, shall I check on the alternator dragging engine or to check on voltage produced? Thanks.


And also need more inputs from others please....THANKS!

 

[anaksarawak]

june, NGV system impossible for me lah, cause no NGV station here...Thanks.



Geoffrey, thanks for your tips, my car has 1 unit of O2 sensor only & i will check on it. also will check on a/c compressor & alternator. I bought bosch platinum spark plugs from bavarian-auto, believe they are original & suit M50 engine. Can you pls tell me more about your tip#7. Thanks.



lefrote, sorry I can't remember when this "makan minyak" happen, but i guess it happen ever since my engine conversion..., i tot is was normal for 2.5 liter, but after knowing you guys are running about average of 0.25 cents/km, i realized that my car is not normal...pls help. Thanks.



keray, shall I check on the alternator dragging engine or to check on voltage produced? Thanks.


And also need more inputs from others please....THANKS!

Hi bro..

The gear ECU might not communicate with your engine's ECU therefore the gear may not downshift properly.. "high gear on low speed consume the most petrol"

Try change back to original spark plugs also have your AFM checked as wrong indicator of air can cause high consumtion of fuel..

If you smell strong odor from the exhause it can be the engine is running rich and if this happen. you need to have your car re-tune.

Hope it help...

 

[freti]

My friend introduce me to do a special service for my BMW. but when i went to the shop where my friend told me , ( somewhere near to melaka perdana ) the shop was always closed.

Then I phone to the person who leave then number on the shop door, then they come to take my car for service. Actually it was a scary experience, it is my new car, i just bought my new BMW, i am so worry that they will just "killed"my beloved car.

after 40 minutes, they finished the service and at the moment i started my car, i felt something strange, and when i started to drive, i couldn't believe it is my car!! it is so smooth in driving and powerful!

i am driving it already 10 days , just empty my petrol tank and refuel to full tank. ( my goodness, petrol price increased !! )

I am not very good in calculation ,but i used to reset my km meter to 0 after every refuel . I found that my km increased !! it means my comsumption decreased!!!

That service gave my car more power, and even save my car comsumption!

I am not trying to sell , just simply let you guys know such service exist and it is really helpful.

here is their website address which i see writen on the name card :

Link to the service center

 

[laneza]

what i can suggest here TUNE back your ECU...check ur injector+ service/change air filter..make sure u use bosch fuel pump :top:

 

[viewfinder]

Possibility that some sensors were not plugged in correctly during the conversion?

Have you checked the air flow mass sensor also?

 

[flash]

Well, wan520i, at least yours is not as high as mine, with the new fuel prices, I am now hitting 42 cents per km. Tried everything, changed injectors, MAF, ECU, plugs, coils, fuel pump, fuel regulator... except changing the engine.... Now strictly my weekend car.:smokin:

 

[tkk]

a friend of mine using 540i V8 auto. The FC is about 0.50 per-km now.