groove66

yes, I would check the smooth running portion. if you see the misfire fault counter go up in number. move the injector to another cylinder and see if it follows..

I also work at a indy shop in Santa Monica and I have a e55. if you are interested we can take a look. I know my way around star/das.

Gadget

Just do a compression test. If it is shows low compression in a cylinder you have your answer.

If the compression test is good, then you know the engine is mechanically healthy and you can look at injectors, plugs and coils, you know, the easy stuff.

You can spend a lot of time playing with the other things, but if you have low compression you are just wasting your time.

G

06cls55amg

try getting your injectors rebuilt. thats what fixed my issue.

Ken311

Update -

Compression test was good. Hooked the car up to STAR and there were occassional misfires on all cylinders. We pulled the fuel rail off the car and flow tested the injectors, they were all fine. The culprit was found to be faulty plug wires, even though this set had only a thousand miles on them. With a new set installed, the misfires were gone according to STAR and driving around I could feel a noticeable improvement in smoothness.

However, the same symptoms persist both around idle and when the supercharger kicks in. Surging on deceleration is still present as well as jerkiness during on/off throttle.

I'm thinking the throttle body/actuator may be going, but can this be possible with no fault codes? Could a malfunctioning MAF/MAP sensor or CPS sensor be causing this without fault codes? Idle control valve?

Ken311

The car is at the shop today to diagnose any throttle actuator issues & replace the MAP sensor. Also checking fuel pressure. Hopefully some insight will be had...

groove66

It could possibly be your TCC lock up going bad. Also follow the hiccup thread

dmoney1009

Can you show where I can find this in DAS, I would like to run this on my injectors to see if they ****ing up.

Ken311

So...last trip to the shop showed fuel is good all around. MAP sensor was replaced but did not make a difference. I wanted to try swapping out the original throttle body for a new unit to see if it fixed anything, but we couldn't get a re-mani'ed piece and a new one can't be opened and returned. Decided I didn't want to spend $1k+ on a hunch that might not fix the issue.

In the meantime I've been looking for used throttle bodies as a "test" to see if it will help (or at least change in some way) the part-throttle and idle issues. I found a used one off of a '03 SL55. I'm assuming the motors are identical so would a direct swap work here? I believe they are both 74mm.

Thanks

Quadcammer

Ken,
any updates on this?

to update on mine, I bought a star DAS and looked at everything. No engine or tranny codes...in fact no drivetrain codes at all.

I looked at smooth running and the fault counter. Zero faults in all holes and only cylinder 7 had a smooth running variance of .63 which appears to be well within spec.

so pretty plain the engine is running ok. Gotta be tranny or possible a cv joint as shown here:

https://mbworld.org/forums/c-class-w...ping-halt.html