Rough idle when cold...smooth when warm..?
03-05-2014, 05:32 PM
#26
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Join Date: Jul 2012
Location: Canada
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07 E63 + 07 CLK63CAB
You are quite welcome Ken, glad it worked out for you. Have seen many on these sites that show black filters when replacing their tired fuel pumps, which makes me wonder just where they buy their fuel. Stick to a reputable gas station that has updated tanks, not just going to the nearest station or for 3 cents cheaper. Have pulled fuel filters out of tanks with 85k miles and the prefilter is a golden yellow, the colour of gas in a bottle, not sure where the black gas comes from
Again Glad it worked for you.
Again Glad it worked for you.
09-23-2016, 04:34 PM
#27
Super Member
Zombiecustoms, what exactly were your symptoms? Shaky idle all the time or only when cold then it smooths out?
09-26-2016, 02:03 PM
#28
MBWorld Fanatic!
When was the last time the fuel filter was changed?
It's required service around 60K miles.... expensive, yes but important. A lot of guys seem to miss this service item either because they think it's too expensive (~$600) or they just never realized it was supposed to get swapped out.
Clogged filter = low fuel pressure & flow. At WOT, you could end up starving the motor for fuel... and that's when the REALLY expensive problems happen.
I don't know if there is a way to read fuel pressure through the OBDII port or not, that would a convenient way to do a quick "sanity check" on the condition of your fuel filter/pump....
-G
It's required service around 60K miles.... expensive, yes but important. A lot of guys seem to miss this service item either because they think it's too expensive (~$600) or they just never realized it was supposed to get swapped out.
Clogged filter = low fuel pressure & flow. At WOT, you could end up starving the motor for fuel... and that's when the REALLY expensive problems happen.
I don't know if there is a way to read fuel pressure through the OBDII port or not, that would a convenient way to do a quick "sanity check" on the condition of your fuel filter/pump....
-G
Good idea. But, obd2 does not give fuel pressure readings from what I can see. What about AFR guage to see if its going lean? Think that would give same sanity results?
09-26-2016, 02:06 PM
#29
MBWorld Fanatic!
Nice
09-26-2016, 02:13 PM
#30
Super Member
Which has opened up a whole new can of worms for me. I am noticing consistently high +5% to +7% LTFTs. I know thats within the acceptable range but how come i am never seeing below +3% and Ive been monitoring for months. From what i understand, they should be bouncing between slightly positive then slightly negative.
And now that its getting cooler out, they are creeping up to no lower than +5% no matter what. Im at 75,000 miles and dont believe i have any air leaks but im very concerned that I have a lean condition according to these LTFTs. My tank and pumps are new so i cant imagine thats it.
During this whole time, I had a EuroCharged tune but now I also have an 83mm SC pulley on the car ...if that matters...
Last edited by V-AMG; 09-26-2016 at 02:16 PM.
06-19-2017, 12:08 PM
#31
Member
Now you have cleaned the throttle body, next clean the injectors, in a half tank of good fuel put 2 bottles of techron fuel injector cleaner, drive until below 1/4 tank then refill to half tank. This should help, at the mileage you have the injectors become gummed up and the atomization of the fuel is not perfect and will sometimes produce drops of fuel not a good spray pattern. This is more prominent when the engine is cold and could been seen as rough idle and shacking. Worth a try is it not.
Good luck
Good luck
Thanks,
