CEL Funny Idle???

[BMW G]

did a little bit of spirited driving today until the CEL went on. drove fine like nothing happened. i go tit home and noticed the idle dipped up and down but nothign drastic.

any ideas?

thanks

[wolfgangstbd]

idle control valve? i had a massive vacum leak and the cel came on so i sealed it (hose fell off haha) then taped the icv with a metal stick and a hammer cel went away. icv can get stuck because all the oil from you crankcase vent runs through there and gets it really dirty

[BMW G]

idle control valve? i had a massive vacum leak and the cel came on so i sealed it (hose fell off haha) then taped the icv with a metal stick and a hammer cel went away. icv can get stuck because all the oil from you crankcase vent runs through there and gets it really dirty

thanks for the feedback! i checked all the vacuum hoses and they all seem to be fine and new. the idle has been slowly getting worse which leads me to believe its the ICV. anyway to properly clean these? how much does a new one cost?

[wolfgangstbd]

you just take it off spray brake clean in it and wd40 if you want to lube it then put it back

[sector6]

did a little bit of spirited driving today until the CEL went on. drove fine like nothing happened. i go tit home and noticed the idle dipped up and down but nothign drastic.

any ideas?

thanks

Mine is doing the same thing at idle. Fluctuates one or two hundred rpms from the norm.
When you were driving, did the CEL go on and off? When mine comes on, I noticed if I let off the gas the light goes off but always comes back on shortly after.

Haven't had too much time to investigate yet.

thanks!

[BMW G]

you just take it off spray brake clean in it and wd40 if you want to lube it then put it back

i'll try this out thursday and post results

sector6

i just happened to look down and saw it on. its at a constant on and didn't intermittently (sp) go on or off. i'll keep this updated until i solve the problem...hopefully

-G

[BMW G]

just took the ICV off and cleaned it with brake parts cleaner as suggested and wd40. it made teh idle higher and now it stays at a constant 1k RPM.

i wa looking at the intake boot and its ripped but nothing too too bad that would of affected the idle since it has been this way for quite some time

as a recaution i ordered a new boot from the dealership and hope for the best.

[wolfgangstbd]

any small holes in any vacumm line or intake boot will affect your idle

[BMW G]

any small holes in any vacumm line or intake boot will affect your idle

hopefully this is the problem. we'll find out tuesday

[Cobra Jet]

instead of guessing what *might* be wrong, do this...


turn the key to "on" without starting the vehicle, stomp the gas pedal 5x consecutively in an even fashion. The next thing you know, your CEL will start blinking - COUNT the number of flashes. Each stored code is (4) digits long, so it will blink the code as such:

1-4-4-4 = no stored codes, so the "flash count" for this will look like:
flash-pause-flash-flash-flash-flash-pause-flash-flash-flash-flash-pause-flash-flash-flash-flash-pause-end.

IF more than 1 error code is stored, the NEXT code would proceed the longer pause after the 4th digit flash and again, you would need to count the next set of flashes and look up the code. After the DME has flashed all of the stored codes, it will repeat the first code and those after it over again.

IF there is only (1) error code stored, the flash sequence would then repeat only that error code over and over until you turn off the car/key.


You will get error codes for nearly every sensor or issue that can be recorded into or by the DME.



The ONLY error code that never seems to be stored or registered in an E30 M42 DME is the failure of the CPS sensor (crank positioning sensor). When the CPS fails, for whatever unknown reason, the error code never registers and is never stored/picked up by the DME, even though an actual code exists. This has been a topic of discussion on multiple BMW sites regarding this type of problem w/ the E30 M42's. So, if your car will never start one day and you've diagnosed every other possible non-start issue and all of those other components are working properly based on specs & procedures, consider the fact that your CPS is indeed dead. When you go to do the code extraction as shown above (and no other codes exist), the DME will just spit out a 1-4-4-4 and the final conclusion is the CPS has crapped out so it will need to be replaced. Do not buy another used one, just buy it new.

:)

[wolfgangstbd]

i just use a diagnostics computer haha. its something bigger than a vacum leak if the cel is on imo

[BMW G]

i just use a diagnostics computer haha. its something bigger than a vacum leak if the cel is on imo

What scanner do you use and where did you get it?

jet, I've tried the stomp test several times and at different stomping patterns and speeds. It does not want to work for me.

[wolfgangstbd]

my school has a modus

[BMW G]

Thanks

Well I installed the new intake boot and the idle straightened out and the car runs and drives much smoother. Anyway to clear out the CEL? I know how to rese the service lights.

[Garageaholic]

Anybody know how to reset the CEL? I have one in my 540i