So I did an initial fact-finding on why I have a high Idle issue (830-850) RPM. It appears that I don't have a vacuum leak, but after I hooked up the Idle RPM with Xentry checked out, and set the throttle angle to 5.0 it would run at 530-550RPM adjusting it to 10.0 it would run at 630-650RPM for s short period of time and then go back to 830-850RPM.

I, therefore, think my throttle body needs cleaning or to be replaced in order to stabilize. I'll report back after I have had a chance to remove it from the engine for a good cleaning/inspection.

Best HK.

 

Throttle butterfly have enough ick on it to occlude airflow at small openings?

None of my bent-12 engines have ever collected any crud on them.

I’m betting on the throttle body for a failure assuming no vacuum leaks.

MB did better with vacuum lines for boost with the 279 then the 275 which was forever cooking the boost signals and solenoids.

 

Hendrick... Did you get this solved?

Wondering if a temperature sensor thinks the engine is cold.

I finally got fiber internet. Nice to have this webpage open quickly.

 

John,
Time permitting, so far, I found that the vacuum hose attached to the back of the PS intercooler was detached (no idea why). I re-attached it, but it didn't make any difference. The next step was to replace the throttle body with a (used) replacement unit.

It didn't make any difference either, so I will still have to investigate it further. Your hint about a temperature sensor is a timely input for me to consider!
What is the RPM on your car after it's warmed up?

Overall, the car is running fine. I have had it on the lift with the engine and gearbox covers removed, and it all looks good; no oil leaks or drips anywhere.
I looked into doing an ABC fluid flush/ filter change (I am used to doing this on all my ABC system cars). I now realize I must change the reservoir with a built-in filter, as the W222 does not have a separate replaceable filter. However, judging by the color of the system fluid (Pentosin), it is still clear and has the usual green tint, so that can wait.

Other than that, I plan to change out the transmission fluid and filter just need to check if the parts are the same as all other 7-speed boxes.

Thanks for chiming in, I appreciate the comments.

HK

 

I will plug it in and see what XENTRY says about idle speed.

 

One suggestion,
Have you looked into why Xentry is flagging a warning on the B37, accelerator pedal, value?
Yes, idle is 0%, but perhaps there are additional signals from B37, to indicate idle? (like that there are additional signal for kick-down).

br,
syljua

 

Thank you, I'll go and check this tomorrow, interesting!

HK

 

Based on the confirmation I got from John, I should be idling at a steady 600 RPM, so I'm now considering replacing the coolant temperature sensor, as it may not send the correct signal to the ECU.

Attached is the part number

 

An Ohm test of the sensor will tell you if it is alive or not. Preferably via the connector at the ECU to include all resistance in the circuit.

In most cases more resistance is colder.

 

John and others;

I appreciate all your comments. I was planning to get back to working on the high idle subject sometime this week as I had existing travel plans for 11/19-11/21, checking out a motor yacht for one of my clients in Florida. I got a sudden request on 11/17/23 to do the same for (3) other yachts in the Houston, TX area, so I decided to make a roundtrip from my Rockport, TX location (350 miles in one day) using the S65.

I left for Houston at 5 AM, got there around 9 AM, did all the boat work, and was ready to start my return to Rockport around 4 PM. Just about 20 minutes into this, the car broke down on me on the outskirts of Houston on a hectic 2-way state road. With the engine still running, I did get a 2-3 minute warning on the instrument panel that said to start the engine within xx minutes before the car would shut off before I could find a convenient spot to pull off the road. The car shut off and was utterly dead. Not a single electrical function or ability to restart was available to me.

I guessed that my "Lithium" start battery had failed to get me off this busy road and the car to a safe place to check the car out. I used my "AAA" (with 200 miles towing option) to have me and the car delivered back home that same evening around 9:30 PM.

So the following day (11/18/23), I removed the lithium battery and installed a new AGM battery instead (I had it reprogrammed to work with it). I decided to try to recharge the lithium battery I had removed from the car, and when I found it would recharge, I realized it wasn't the battery that had gone bad but that I must have an alternator (voltage regulator) failure.

After I return from Florida today, I will work on this when I get home. I haven't found any good write-up for this for the W222 S65, so I plan to make one once I get started.

I plan to do this in a new (separate thread) and return here when I am ready to resume working on my high idle issue.

Thanks for all the comments. I look forward to sharing my findings on the charge system (alternator) issue.

HK

 

Hendrick....

Bummer about your run of luck. My offer is $10,000 where she sits. LOL

I got to replace an alternator in my 221 S-65 when it gave me the red light in the cluster for charging.

Don’t know how similar the 221 car is to the 222 coming apart but if failing memory serves....

I got to pull the radiator fan and radiator to get it out through the top. If that is the way it comes apart for the 222 be sure to look closely at the radiator to verify that where engine intake air goes through it the plastic seam for the mold during manufacturing does not have a hairline crack as the radiator in the 221 car decided to leak there. If it has to come out anyway this is a convenient time to replace with fresh. Give it a fresh serpentine belt and idler pulleys while apart as well. Any leakage from a front crank seal? This is the time. Also very convenient time to give it a fresh water pump. Front crank pulley comes off to replace the water pump. No puller needed.

Best wishes.

John

 

John, Thanks for your notes. I'll have some time tomorrow to start on a plan of action for this and a new thread dedicated to it. I have removed (3) times the V12 out of a 2006 W220, so that experience will be helpful to this time.

Thanks for your input.

HK