Hi all, Jason here...new to the forum. Been reading some of your fine work and suggestions so far. Keep up the good work! So, I just bought a 2010 fully stacked with literally everything and in pristine condition appearance wise, along with brand new Pirelli 20's....for 10k. I figured that left a few K to play with to fix up whatever hopefully minor things needed to be updated/fixed/replaced. Also checking carfax recently it has had fuel filter, battery, alternator, oil/oil filter, front sway links and secondary fuel pump fixed/replaced. Car has 134k on it which is more than i wanted...but it just is so damn nice so i went for it based on how she looked and what's already been done. Test driving it it has a clunk in the front a bit....even after sway links done...i find that not a big deal as i can rent a lift and swap out some control arms myself for a reasonable cost. Same with squeaking break pads...easy stuff.

However, after a week of light driving it threw some codes....P0172 and P0175 (system too rich both banks)...and once it threw a P0140 (i think it was...forgot to screenshot that one..that one went away and hasn't been back yet though). So i called the place on the carfax who a month ago replaced the secondary air pump...cause of the P0140 or whatever it was. They said they'd have to check the secondary air control valve next.

So far I have changed dirty air filters, and cleaned the MAF sensor. It's been 38km and no codes yet...but the car seems like it is struggling for air and my guess is they will come back.

Symptoms include:
-Low Idle about 500rpm at idle and 600 in drive with foot on break
-Ticky engine noise when fully warm and at idle
-Seems to get a little hot...middle point is 80 on engine temp...it rides at 90 when warm

Gonna include some ODB live data...only thing that sticks out is Long Term Fuel Trim is high....but driving it today it got down to 3.5%.

I am going to replace MAP sensor and plugs and coils next as it likely needs the plug/coils anyway. Any thoughts or ideas on what to try or look at next? Or do any of these readings cause room for concern?

Thanks if anyone shares their expertise!

 

Actually it was P0410...got my stuff mixed up.

Code P0410 is the result of the Engine Control Module (ECM) indicating a malfunctioning Secondary Air Injection System. This happens when the O2 sensor does not accurately detect the changes in the O2 level of the exhaust while the air injection system is functioning.Oct 30, 2018

 

Welcome!

No worries on the engine temp. It's perfectly normal, which should be about 87*C when fully warmed up.

I don't know much about the gassers, but I would probably plan on doing spark plugs if they haven't been done. I hear it's a bit of a PITA on GLKs, but there are write-ups of folks who've done it before which should help.

As for the fuel trim being too rich: could be any number of things, from dirty injectors not spraying the correct pattern, questionable fuel, insufficient air (make sure MAF numbers align for requested vs actual).

I'd probably run some concentrated and quality fuel injector cleaner along with premium gas (always premium!) for at least a couple tanks and see how it goes.

Others with more experience on gassers will chime in. In the meantime, there's plenty of reading available if you look for it

 

My 2010 has 80K miles and ticks at idle. I assumed they all do it.
For injector/fuel system cleaner, I highly recommend Techron.

 

Thanks for taking the time to respond! Yeah I dumped some Lucas Fuel Injector Cleaner and filled with Premium for the 1st fill up since getting it. Since changing filters and cleaning MAF as well...oddly the codes aren't back after 40km yet. And the idle jumping around periodically I haven't noticed either. Seemingly these things alone have at least helped a little. I have plugs and coils ordered as who knows if those have ever been done at all. Do you know if it takes a bit of driving for the computer to sort of reset and adjust to the new norm after cleaning the MAF? Cause the LTFTrim readings went from 10 down to 3 after driving 20 or so KM after cleaning. Lastly, is 500rpm Normal at warmed idle? Cause the first 10-20 seconds upon start when the idle is at 1k there is no ticking...when it settles down to 500 (which seems low to me) it starts ticking...almost like it still is needing more air intake.

Thanks all you're great! What GLK's do you have?

 

Thanks for the reply Silver Shadow...nice you got same ride as me. 80k is super nice for a 2010. They really are sweet looking rides.

For 1st fillup, dumped in some Lucas Injector cleaner and premium....waiting on plugs and coils...looks pretty easy on our models but tough on the 2013-2015's. Have you done plugs on yours yet? Maybe the ticking at idle is normal on these, never owned one and was just nervous it was something serious.

 

I'm not exactly sure but I think normal idle is somewhere around 600-650 rpms in park/neutral (not in drive or any kind of load). It's good the fuel trim numbers are adjusting/correcting. They are supposed to be constantly adjusting ECU parameters for a smooth idle and power delivery on demand, so it seems they're working. Hopefully a few tanks of good fuel, fresh filters, and those new plugs will make a big difference.

I would suggest an oil change shortly, if you haven't done it or if it hasn't been done within the last few thousand miles. Look for oils that meet MB spec 229.5 (there's a sticky around here about which oils to use), stick to quality filters (Mann, Mahle, Hengst, etc.) instead of cheapo stuff and you should be OK.

At your mileage, I would also strongly suggest new transmission fluid and filter, along with rear diff fluid change. Cheap insurance for your entire driveline and hopefully gives you another 80-100k miles of service.

 

Isnt it normal for the direct injection fuel system to knock at idle ?

 

Mine idles at 650 rpm. The plugs were changed by the original owner about a year before I bought it. I'm planning on doing a tranny fluid change and diff soon.

 

I think "ticking" is an accurate description rather than knock or knocking. In any event, the O.P. has a 2010 with the first gen. engine that does not, I believe, have direct injection.

 

At that mileage it's time to start listening for the bearing failures in the transfer case.

 

As an FYI.....cleaning the MAF sensor vigorously and changing the air filters has helped. I'm at 100km and no codes for "running to rich" at this time. Also w/ the OBD reader the LT-Fuel Trim went from over 10 before doing so and now is sitting around 3. Just wanted to post this in case anyone else has similar symptoms or codes and want to try the easiest and cheapest thing possible as the 1st step! I am going to do plugs and coils next just cause at 134k miles who knows if they've EVER been done.

Thanks guys,
Jason