Check Engine Light.... Regular Gas?


sgtbello
08-12-2006, 04:57 PM
Hello,

Recently my started wife driving the old 1998 740il when the check engine light came on.

She said that the last time she filled the car up she used Regular gasoline and shortly after the engine light came on.

I checked all the standard stuff like the gas cap but the light still remains on. I was wondering if putting in Regular unleaded gas might cause this issue.

Any help would be appreciated.

Thanks.

hwade
03-08-2007, 02:47 PM
Not really sure but ive been told that it could, my manuel says nothing less than 89 octaine, but the service dept said I should use high test. my 740il is a 97 and ii in the usa.

lincolnmaster80
03-09-2007, 11:10 AM
This happend to Marz740il...except when he got his OBD port scanned, it came back with fuel trim malfuntion and he filled up with 89.

http://www.automotiveforums.com/vbulletin/showthread.php?t=681184

I'm curious to know what your error codes are if you've scanned them yet...

hwade
03-09-2007, 01:11 PM
here are the codes ive gotten.
p0150:02 sensor circut, bank2-sensor1 malfunction
P0136:02 sensor circut, bank1-sensor2 malfunction
P0156:02 sensor circut, bank2-sensor2 malfunction
P0173:Fuel trim, Bank2 malfunction
P0308: Cylinder 8 Misfire detected
P0130:02 sensor circut, bank1-sensor1 malfucntion
P0100: not sure?

lincolnmaster80
03-10-2007, 01:19 PM
p0150:02 sensor circut, bank2-sensor1 malfunction
Test O2 sensor on Bank 2 before the cat. Replace if nessesary. Sensor 2 is after the cat (I think).

P0136:02 sensor circut, bank1-sensor2 malfunction
As above. Only on Bank one after the cat.

P0156:02 sensor circut, bank2-sensor2 malfunction
As above...again, except on bank 2 after the cat.

P0173:Fuel trim, Bank2 malfunction
Vacuum leak on bank 2. Might be MAF sensor as well.

P0308: Cylinder 8 Misfire detected
Check spark plug, ignition leads, distributor caps and distributor rotor. If those check out fine, post back here.

P0130:02 sensor circut, bank1-sensor1 malfucntion
As above except on bank 1 before the cat.

P0100: not sure?

P0100 115 Mass or Volume Air Flow Circuit. Make sure the contacts are clean and making contact. It is possible that the connector to the MAF has wriggled loose a bit. If that checks out fine, test the MAF circuits with a volt meter. I can't remember the pin outs or the voltage readings for each pin, I will try to find these. Once you check those and if they read fine, clean the MAF. If cleaning makes no difference, you might be looking at replacing a MAF.

lincolnmaster80
03-10-2007, 01:26 PM
Some incite to cylinder misfire:

http://bimmer.roadfly.com/bmw/forums/e38/5990147-1.html

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