CLK320 M112 Idle Problem
02-20-2018, 01:27 AM
#1
MBWorld Fanatic!
Thread Starter
CLK320 M112 Idle Problem
Hello all,
For those of you who were not following my previous thread, about 2 months ago, I discovered coolant in the engine oil. The oil cooler was first replaced, but the problem remained. Then the head gaskets were replaced, but the problem remained. Then the timing cover and its 2 rubber o-rings were replaced and the problem was fixed.
However, after replacing the head gasket and putting everything back together, the car developed a rough idle where it shakes lightly when in Park and more roughly when in Drive. No errors appear when scanning with STAR/DAS. We tried all the following to fix the problem to no avail:
-Inspected all vacuum hoses and EGR valve and they are ok
-Inspected the spark plugs and they are fine
-Moved the coils and wires around
-Using STAR/DAS, disable circuit A and circuit B of the ignition coils and no errors were registered
-Replaced/swapped the camshafts
-Replaced/swapped the fuel injectors
-Finally, we disconnected the exhaust from the primary cats and downstream and the rough idle disappeared by 80%. When we reconnected everything, the rough idle was still gone by 80% but the 20% remained. We then replaced the O2 sensors, but without any luck.
When the initial rough idle was happening, I connected the STAR/DAS and ran the smooth engine test and faults would appear on Cylingers 4, 5, and 6 but Cylinder 5 mainly as per the screenshot below:
So now, with the "20%" of the rough idle remaining, I can feel it with the car in Park but way more while it's in Drive. I can feel how rough it is by the entire car shaking. Then, say after every 5 or 10 minutes with the car in Park, the engine would start shaking and the car would shake with it, the RPMs drop to the point it feels as if the car is about to shut down and then the RPMs rise above 1000 and it recovers. I have recorded that in a video which can be see here:
So with the above problem occuring every 5 or 10 minutes, I connected STAR/DAS and recorded a video while running the "Test values at idle speed" test. You can find below what is happening with the car as it nears shutting down and then recovering:
The only other thing I noticed is that while running these tests, it says that the Intake Air Temperature should be below 35C while my car is at 71C. Mind you the car is parked, but the outside air temperature is 13C.
I look forward to your expert opinions on trying to resolve this annoying problem.
Thank you in advance.
For those of you who were not following my previous thread, about 2 months ago, I discovered coolant in the engine oil. The oil cooler was first replaced, but the problem remained. Then the head gaskets were replaced, but the problem remained. Then the timing cover and its 2 rubber o-rings were replaced and the problem was fixed.
However, after replacing the head gasket and putting everything back together, the car developed a rough idle where it shakes lightly when in Park and more roughly when in Drive. No errors appear when scanning with STAR/DAS. We tried all the following to fix the problem to no avail:
-Inspected all vacuum hoses and EGR valve and they are ok
-Inspected the spark plugs and they are fine
-Moved the coils and wires around
-Using STAR/DAS, disable circuit A and circuit B of the ignition coils and no errors were registered
-Replaced/swapped the camshafts
-Replaced/swapped the fuel injectors
-Finally, we disconnected the exhaust from the primary cats and downstream and the rough idle disappeared by 80%. When we reconnected everything, the rough idle was still gone by 80% but the 20% remained. We then replaced the O2 sensors, but without any luck.
When the initial rough idle was happening, I connected the STAR/DAS and ran the smooth engine test and faults would appear on Cylingers 4, 5, and 6 but Cylinder 5 mainly as per the screenshot below:
So now, with the "20%" of the rough idle remaining, I can feel it with the car in Park but way more while it's in Drive. I can feel how rough it is by the entire car shaking. Then, say after every 5 or 10 minutes with the car in Park, the engine would start shaking and the car would shake with it, the RPMs drop to the point it feels as if the car is about to shut down and then the RPMs rise above 1000 and it recovers. I have recorded that in a video which can be see here:
So with the above problem occuring every 5 or 10 minutes, I connected STAR/DAS and recorded a video while running the "Test values at idle speed" test. You can find below what is happening with the car as it nears shutting down and then recovering:
The only other thing I noticed is that while running these tests, it says that the Intake Air Temperature should be below 35C while my car is at 71C. Mind you the car is parked, but the outside air temperature is 13C.
I look forward to your expert opinions on trying to resolve this annoying problem.
Thank you in advance.
Last edited by xsever; 02-20-2018 at 03:33 AM.
02-24-2018, 03:51 PM
#2
MBWorld Fanatic!
Thread Starter
UPDATE AND SOLUTION:
So after replacing the MAF seals, trying a new MAF and a new throttle body, the problem remained and the smooth engine running test on STAR kept showing cylinders 4,5,6 not so smooth so we elected to skip the timing chain one tooth on the driver side of the camshaft and voila! the car went back to being silk as smooth.
So after replacing the MAF seals, trying a new MAF and a new throttle body, the problem remained and the smooth engine running test on STAR kept showing cylinders 4,5,6 not so smooth so we elected to skip the timing chain one tooth on the driver side of the camshaft and voila! the car went back to being silk as smooth.
02-28-2018, 11:23 AM
#3
Senior Member
Hmm. I seem to have a similar issue with the rough idle. Is there any way to check this using a cheap ODBII scanner instead of STAR? Wondering if there are any parameters I can try to graph.
03-01-2018, 12:22 AM
#4
MBWorld Fanatic!
Thread Starter
I have a cheap ODBII scanner which I did use to graph many parameters in the hopes of finding what's wrong but with no luck. The parameters that you need to spot this problem are Injection Time Right and Injection Time Left which STAR can display. These times for me were off by 0.5 ms. When we skipped the timing chain a tooth, the times went back to be the same and the rough idle was fixed.
