Heavy Fuel Consumption Joke?

[haffeel]

My ride E30 325i Auto normally does Kms 400 on a full tank when the needle just about touches the RESERVE orange lamp comes on. Which means I could do Kms 450 on a full tank thearotically.

But lately I am getting lesser and lesser mileage. Now when I hit the Reserve Lamp On I have done less than Kms 300. I am really depressed with this new development now that Fuel prices are sky rocketting and this is my daily drive car which I use for work as well.

Ah haa today I caught the culprit broad day light. I noticed my odometer is doing much less mileage than what it should.

For a distance that should show me Kms 35 it was reading less than Kms 20 that is Kms 15 discrepency.

So gentemans, my car ODOMETER DIGITS COUNTERS are actually running too slow.

How can I fix them to run normal or accurate?

I dont see any discrepency in the speedometer reading.

thank you,

haffeel

[TheDutch]

Ah haa today I caught the culprit broad day light. I noticed my odometer is doing much less mileage than what it should.

Excellent words.

Anyway - is the speedo reading correctly, or have you been going 50% quicker everywhere too?

[haffeel]

Hi dutch,

Simply put, the ODOMETER is faulty, it reads slow. what confuses me is that I dont see the SPEEDOMETER behaving funny. I know the speed information coming from the differential. The SPEEDOMETER is responsible to give correct reading for the ODOMETER.

How come here the SPEEDOMETER behaving ok when the ODOMETER is not.

I suppose those tiny plastic gears some where must be jammed. It was working OK until last couple of days.

Has any one come across this problem?

TQ

[haffeel]

OK I found the answer from this forum

ros
E30 Zone Newbie


Joined: Jan 10, 2005
Posts: 245


PostPosted: Thu Mar 24, 2005 9:00 am Post subject: Reply with quote
Ahem.

The speedo unit has 4 pins: +12, gnd, diff pulse in and cleaned up diff pulse out. A single chip drives the odo via a stepper motor & gearbox and the speedo via a current sink through the galvanometer.

If the speedo works, then the problem is either a broken/ceased gear or a dry joint on the speedo sub module (most likely the pins going up to the stepper coil).

[haffeel]

OK today I timed my ride going on the highway while passing each mileage blocks on the road.

My speedometer is reading exactly ONE KM for every TWO KM ride.

which means the meter is running exactly 100% slow.

Do you guys think this is a mechanica problem or electrical?

If it is mechanical then I might as well buy another unit from the chop shop.

Has anyone successfully fixed a problem like this if it a mechanical problem?

TQ

[Mops]

so your speedo reads speed ok, but the odo reads 50% of actual distance ?

[haffeel]

Mops, yes you are right! the ODO is running at half speed.

when I find the time, I am going to open it up and do some maintenance, or may be even change the whole cluster if I can get it for reasonable price.

Add to this pain, I also found my fuel hose at the injection rail has hardened and cracked. When under pressure I was loosing fuel heavily

I changed the fuel lines both incoming and return. So I see more mileage now.

One more item I got to check and change is the Fuel Filler neck. Looks like there is a leak in that section as well. As I pump full tank, after a drive when I get down from the car and come towards passenger side I smell fuel. Yuks

I suppose these are the challenges we got to face for having such an old car

thats the fun part in some strange ways !!

[Gwynleym10]

surely thats a good thing that your not cranking up the mileage???!!!

[haffeel]

I found the problem, One tiny gear has lost all its teeth in the ODO meter trip counter. It cost me 29 Pounds to fix 3 tiny plastic gears. Rediculars

Anyway now every thing is normal.

I think now that all the counters working time to change Engine Oil, I have overshot the change duration limit.

cheers