Recently replaced the engine mounts in my 48k-mile 2009 E63 and the improvement that made is amazing. However one thing is different/wrong now: I had the battery disconnected for 24 hours while replacing the mounts. Now the hot idle speed runs at 900-1100 in neutral (and hunts in RPM a bit) where before it was 600-700 and probably because of that, city MPG is down about 10%. Cold startup RPM, warmup RPM are all normal. It's only once the oil reaches about 80C that I notice the high idle speed. I inspected underhood for vacuum leaks etc but everything looks/sounds normal. Power delivery is normal.

Is there a specific procedure to be performed if the battery is disconnected for a day? I replaced the battery mid last year and other than reprogramming the windows and pano roof, nothing changed engine-wise.

 

I have a 2007 E63, and am having the same issue although it just started and was not after another repair, I have tried throttle adaptation and idle reset with no success, exhaust smells rich and terrible, and after a minute of driving when first started, goes into limp mode with 0 throttle response and esp light on.

 

did you diagnose with Xentry ?

 

No, but I did use BlueDriver. Checked lambda trims, which were within 1%; no faults; coolant and inlet air temps seemed reasonable so those sensors should be OK. One thing I found odd but probably normal for these engines: hot ignition timing at idle is 9 deg ATDC. Never seen timing that late in other engines.
Another strange thing was that while the bluetooth dongle was attached, hot idle speed was actually pretty normal.

 

Finally decided to remove the intake manifold to at least rule that out as the cause of high idle speed when hot. Instead of ruling that out, found serious amount of the typical throttle body support plate corrosion, and could even see light through the corrosion, so I ordered an RMT throttle body plate. Strange thing is startup/cold idle speed was always normal, which threw me off with this diagnosis.
Question for you guys who've had these manifolds apart: do you use anti-seize on bolt threads? I found corrosion in the magnesium threads so something ought to be applied here. STAR Tekinfo does not say anything about this.


11 years old with 50k miles

 

Yup! I bought my 2007 E63 in 17' and after picking it up from the body shop, I noticed the same as you only worse! My RPM's were hitting 15-1800 causing aweful downshifts on my first drive home! Next day I removed the Intake and over the course of the following 7-8 months I ended up taking out the Heads to be rebuilt by XTreme Heads (8 of 16 Intake Valves Bent) And I installed the SLS Valve Tappets, had my Intake itself rebuilt by RMT who installed one of their beefy Throttle Body Plenum's, which was also riddled with holes like yours only worse ( you can buy the direct on eBay), rebuilt the entire front suspension with rebuilt (RMT) air Struts, F1 Fab Adjustable Front Camber Arms, OEM Crash Bolts to correct a pull to the right, new BJ's, costume built HP PS Hose w/New reservoir, UPD Billet Pulleys, New Head Bolts of course!, along with spark plugs and injectors, Catch can, Racing Brake Rotors/Pads and their Hub bolt kit!!

Got to drive it maybe 6000mi before the Rear Main started leaking! So in May of 2020 during the coved scare I put her up on stands as high as I could get it to clear the Transmission, I installed the Rear Main using new flywheel cap bolts, cleaned the TCU, added new trans shifter Bushings I hadn't realized were shot, removed the whole rear Subframe and rebuilt it with K-Mac Bushings for the control Arms, new OEM Subframe Bushings, new Torque Arms along w/OEM Bushing in the Carrier, UPD Rear Toe Arm's, new disc's on drive shaft, while Iwas at it I made sure to remove as much surface rust on the Trans and Diff flanges and treated them with Permetex anti-rust and the Spray painted them as well as parts of the drive shaft and Subframe that were dinged up, Plasti-dipped the E-brake Cables as they were cracking on the surface, Changed the Gearing from 2.82 to 3.06 in the Rear Diff, new Rotors/pads/Hubs/flanges, rebuilt Rear Air Springs (RMT) and new rear shocks, cleaned the Oil laden Exhaust w/WD40 and a scuff pad (one that plumbers use to scuff copper pipe that resembles a window Screen only much beefier) connected to VRP shorty manifolds. I days away from finishing up as I need to install new headlights and swap out the outer lenses and Install new D1S Osram HID's and new inner lenses! That requires removal of the front bumper. Also have speakers, Audison DSP and Amps to install as well as fix the vacuume hoses behind the driver seat and fans!!! Can't wait to hit the road for a big road trip!!!