E30 325 - Ultra bad gas milage -13 mpg Need assistance!

[mgromero]

I just bought a brand new white sensor here in Argentina, was the last one on the $tealer.
Thanks for your input jlevie.


In a glass of cold water is measuring 2900-3000 ohms
in a glass of hot water from the dispenser is measuring .67 and going down.

So i suppose that this one is working fine.
I would provide a new update today at night when the new sensor is fitted :P

[mgromero]

the sensor swapping will wait until tomorrow, I dont have the right tools to remove that little fu$12ck23r. the place and positions that this sensor have is a PITA.

But a new question: what is the thing circled in red in the attachment?
Next to the airbox. it have some kind of sensor with a plate, a spring and a circuit somewhat similar to the board in the AFM.
The carbon track of the board is totally scratched.

[paperplane94]

hmmm

That looks like an intake air pressure sensor.

http://www.ebay.com/itm/BMW-E30-Air-...809#vi-content

[mgromero]

Thanks to all.. new sensor fitted in with the help of one of my friends.
I unplugged the air pressure sensor since I live in the flattest part of my country near the sea.

As you can see the old sensor was rusted to hell... more updates in the next full tank fill :P

[Click]

I suspect that my car is getting rather horrid gas mileage but am not able to prove it due to a broken odometer. Very interested in seeing the results.

[mgromero]

updates:

The sensor change was an easy task, its giving me correct readings in ohms when hot and cold... but......

the milage plumetted!!!!!
now is doing 12MPG, or 5km/L or 20Km/L

This is pain in the a$$ to troubleshoot.
Does someone have the correct values that an AFM must have when operating?

I need more information or this car is going to eat my kidney, legs and all my hair..

[_r2h]

You get less mpg than my C5 corvette!

[paperplane94]

updates:

The sensor change was an easy task, its giving me correct readings in ohms when hot and cold... but......

the milage plumetted!!!!!
now is doing 12MPG, or 5km/L or 20Km/L

This is pain in the a$$ to troubleshoot.
Does someone have the correct values that an AFM must have when operating?

I need more information or this car is going to eat my kidney, legs and all my hair..

Not while its running, but you can bench test it.

If someone has, lets say, messed with the toothed cog in the AFM then it could lead to horrible gas mileage. So if you are not sure if it was tampered with, swap it!

Otherwise, go ahead and bench test the AFM to see if its putting out the correct resistance values as you open the flap.

Bench testing the AFM:
http://www.iprimus.ca/~trauttf/temp/AFM/

[mgromero]

Does someone have an AFM not tampered to sell?

[mgromero]

Quick questions:

- wich is the "correct" behaviour for an Eta engine regarding to RPMs going up and down, I mean, how fast goes up, how many time the engine take to go back to idle when releasing the throttle?

When I step on the gas to rev it .. is going up pretty quick, then I release the throttle and is going down rather slow, then it make a "step" going up and then again.. back to idle speed.

This is normal or the car is rich/lean?



Thanks to everyone!

[paperplane94]

HArd to tell just by a video.

You must take it someplace that has A/F ratio testing equipment.

[E30-325iS]

When checking the resistance of the Temp sensor measure it at the sensor and at the ECU, they should be close, if not look for a wiring problem.

[BrassDrummer]

Seriously, those sensors are like $7 a piece... Just replace them both.

[mgromero]

Seriously, those sensors are like $7 a piece... Just replace them both.

Wich 2 sensors are you referring to?
I just replaced the ECT, wich one Im missing?

Thanks!!

[MTechnikII]

I had the bad MPG problem with my 1991 325ic automatic here in Losangeles, I changed what ever was changeable, AFM, gas regulator, plugs, filters, sensors, O2 sensor and the MPG was about 10 to 11 MPG .
I did the service on my car based on bently's commendation, and did a valve adjustment, nothing changed
then I tried to go wider on the valve clearance by 10% , the gas milage improved imediatly
from 10 11 went up to 17 18 in the city
try wider clearance on the valves see what happens, I understand each engine is different but give it a try, at 5$ a gallon anything is worth the try
Good luck
Henry
and please keep us posted on the progress.