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View Full Version : Check Engine Light & 35+ MPG ???



zedtech2000
08-31-2005, 10:31 PM
Hello everyone! My Check Engine light has been going on and off quite frequently (every few minutes or so) on my '91 525i. I have tried the stomp test and I cannot get it to work. I have owned the car coming on 2 years in a couple of weeks and have never had the Check Engine light come on before.

There is also another weird phenomena... From around the time that the light started coming on (about a week and a half to two weeks ago) I have been consistently getting somewhere between 30 and 40 mpg while cruising the highway, at speeds from 40-60 mph. It is almost unreal, and the car has been abnormally smooth. I don't know what is going on, but I would like to know before it suddenly explodes on me. I just started using oil for high mileage cars (I am at 102,000) and I don't know if that has anything to do with it. Please help me!

Thanks a lot...
Andy

632 Regal
08-31-2005, 10:41 PM
wow...sounds like a cool problem to have!

The stomp test is hard to get right, first time I tried it took like a dozen times with an overnight break before I tried again and finally got it.

zedtech2000
08-31-2005, 10:43 PM
wow...sounds like a cool problem to have!

The stomp test is hard to get right, first time I tried it took like a dozen times with an overnight break before I tried again and finally got it.


I will go back and try again. Thanks!

632 Regal
08-31-2005, 10:46 PM
its like the first time you have to remove the rear seat...pull and pull and think that people were messing with you when they told you thats what you have to do.

You pretty much need a code if you dont have any symptoms. You could also try to reboot the computer andsee if the light goes away, this has worked a bunch of times.

theonew
08-31-2005, 10:50 PM
I often have trouble getting the stomp codes to display. Sometimes I have to try it four or five times. I've found that it seems to help if you have the fan in the off position when you turn the key as well as having any other electronic devices switched off. I've also had better luck not pressing the pedal down too quickly and making sure that I feel the click of the downshift button on each press.

zedtech2000
08-31-2005, 11:08 PM
I GOT IT!!! I think a note needs to be made saying that the 5 stomps need to be done within 5 seconds of the key being turned. When I was trying it for the second round it kind of clicked in my little head that maybe the 'within 5 seconds' meant not 5 seconds within the start of the stomping, but the turn of the key... : )

Anyway, the code was 1221, and it kept looping. It did not stop like the instructions said. As far as I gather it is the first oxygen sensor. Should I replace it? Look at it? Leave it? And where is it? (is it right after the filter box in the front?)

I thank both of you for your help thusfar... And I never could get those rear seats up. Maybe I should try that again too (any suggestions?).

Thanks again,
Andy

632 Regal
08-31-2005, 11:28 PM
pull hard and dont drop your sack to the floor.

I would reboot the computer first and see if the code goes away before messing with the sensor. Almost anything can trigger a false O2 code, if it returns after a reboot then look closely for vacumm leaks and as a final resort change the sensor out.

SRR2
08-31-2005, 11:36 PM
This was a favorite prank in my circle of friends when I was in college. Every so often an extra two gallons (any more and you might notice it on the gas gauge) was slipped into the target's car's tank. Then you sit back and wait for him to start raving about the great mileage his car was getting. Of course, in those days a gallon of gas was a bit less expensive. So do you have any comfortably well-off friends given to practical jokes?

uscharalph
09-01-2005, 12:12 AM
"And I never could get those rear seats up. Maybe I should try that again too (any suggestions?)."

I like to get the back seat out one side at a time. It's usually real hard the first time you do it if it hasn't been done in a long time. Get in the back and get both hands on the bottom lip and pull straight up a good jerk. Once that side has loosened, do the other side.

uscharalph
09-01-2005, 12:14 AM
This was a favorite prank in my circle of friends when I was in college. Every so often an extra two gallons (any more and you might notice it on the gas gauge) was slipped into the target's car's tank. Then you sit back and wait for him to start raving about the great mileage his car was getting. Of course, in those days a gallon of gas was a bit less expensive. So do you have any comfortably well-off friends given to practical jokes?
That prank wouldn't work in these cars with the OBC, which gives you a digital reading of your MPG.

zedtech2000
09-01-2005, 12:24 AM
This was a favorite prank in my circle of friends when I was in college. Every so often an extra two gallons (any more and you might notice it on the gas gauge) was slipped into the target's car's tank. Then you sit back and wait for him to start raving about the great mileage his car was getting. Of course, in those days a gallon of gas was a bit less expensive. So do you have any comfortably well-off friends given to practical jokes?


I don't think so. I am getting my mileage from both the computer and the gauge right under the Tach, and I would assume that they are accurate, but I honestly don't know. I also base by assumption on the fact that the car is running unbelievably smooth, and it feels like it is using very little fuel. Which is good, since here in the Chicago Suburbs, gas is $3.50 (for premium) and MANY STATIONS ARE OUT OF GAS (thanks to the panic over Hurricane Katrina)!!!!!

And is it possible that my seats do not come out? There is no strap that I can find to pull them out and they look pretty attached. There have been a few things different in my car, such as no cabin air filter when there is suppose to be one.

Oh, and while we are at it, any suggestions on new front struts? My desperately need replaced.

Thanks a lot!
Andy

uscharalph
09-01-2005, 12:39 AM
I don't think so. I am getting my mileage from both the computer and the gauge right under the Tach, and I would assume that they are accurate, but I honestly don't know. I also base by assumption on the fact that the car is running unbelievably smooth, and it feels like it is using very little fuel. Which is good, since here in the Chicago Suburbs, gas is $3.50 (for premium) and MANY STATIONS ARE OUT OF GAS (thanks to the panic over Hurricane Katrina)!!!!!

And is it possible that my seats do not come out? There is no strap that I can find to pull them out and they look pretty attached. There have been a few things different in my car, such as no cabin air filter when there is suppose to be one.

Oh, and while we are at it, any suggestions on new front struts? My desperately need replaced.

Thanks a lot!
Andy
There is no strap hanging. The handle you might be referring to is a hand hole cutout to allow you to carry the bottom of the back seat.