Kompressor problem.

[John Jones Jr.]

Suddenly Losing boost at high rev's (4000-4500), from then on at any rev's there's no boost. Switch the engine off & restart all o.k..


Any ideas?

[melk]

hmmm. yeah I seem to recall someone else having this problem. think it's a safety feature, the system is detecting something is wrong so it shuts it off to avoid any damage. wish I could remember more details. seems electrical though.

anny chance you are friendly with a repair garage that has one of the star scanners for the diagnostic port under the hood?

[KrumB]

Please describe exactly how this occurs.

I had a problem similar to what you describe. It occurred when the revs hit the limiter and then no throttle response at all. Engine working at idle. After restart everything back to normal.It turned out to be a throttle body issue. It had to be re-calibrated in a MB service station. Took 10 mins.

[John Jones Jr.]

Hello, Melk. Glad somebody has heard of a similar problem. Yes, I'll get STAR on it but can't do that for a couple of weeks between one thing & another. Thanks for your input.

[John Jones Jr.]

K-B, no need for me to hit rev limiter, all I got to do is hit somewhere around 4000-5000rpm and the S/charger shuts down and car drives like an N/A from there on. Switch the engine off & restart it, the S/charger is back working 100% until I hit high rev's again.

[KrumB]

What you describe is quite different from what I experianced. You need to check it with star diagnostic.
Keep us posted.

[John Jones Jr.]

K-B, do you know if low fuel pressure would send the ECU into a fail safe mode, i.e shutting down the s/charger?

[KrumB]

I've got no idea but I think if the fuel is insufficient the ECU should cut the sprk/ignition not the supercharger.
I've had lean mixtures like 18 (afr) and nothing like that happened.
When you go to the MB service station you can ask them to measure the fuel pressure just to be on the safe side. It takes 5 min.

[KrumB]

Look what I just found on BenzWorld:

http://www.benzworld.org/forums/w202-c-class/1517762-1999-c230-kompressor-supercharger-appears-cutting.html

[John Jones Jr.]

That's sounds like my problem, well done. But what's an 'oil seperator' and where is it located, any ideas?

[Mike51809]

Oil seperator is the same thing as a positive crankcase ventillation valve (PCV). When you look at your motor on top of the valve cover on the left there is a black box with a hose to the airbox and other tiny hoses on the bottom, thats the oil seperator. I think its about $40 over here

[John Jones Jr.]

Ah, the PCV, got it. Thanks Mike. I checked that sometime back & it's clean as whistle. But I have an update.

This morning I replaced the cam position sensor thinking this could be the problem, no cure - still losing boost at high rev's. Anyway, later on I decided to disconnect the battery just on the off chance. Left it for about an hour & reconnected. The car is driving like a different car, even the exhaust note is different - quieter too. Also, I did floor the throttle a few times and no loss of boost! Fingers crossed. But I know tomorrow as I'll be taking a 200+ mile trip.

[KrumB]

Fingers crossed J

[John Jones Jr.]

Any ideas K-B why the car is different?

[KrumB]

The ECU is self adjusting/adopting. It's starting from 0 now so it should be different. It'll come to it's sweet spot after 200 miles. :)

[John Jones Jr.]

260 mile trip completed, car back to normal & pulling like train. Now, I want more power! :D

[KrumB]

:) Good to hear car is OK!

About the power....stop right there!...... :) :)

[melk]

Smaller pulley is easiest way. Or port and polish the supercharger housing.

[John Jones Jr.]

:) Good to hear car is OK!

About the power....stop right there!...... :) :)

It's tempting! :D

[John Jones Jr.]

Smaller pulley is easiest way. Or port and polish the supercharger housing.

Indeed it would seem so, Melk. I've been doing a bit reading up on it and had the local machine guy inspect the S/charger pulley and he reckons it's a every easy job for him to turn down the pulley to 84mm. Worth considering if nothing else.

[KrumB]

84 mm is too small. Smallest you can go safely is 87 mm. Then you'll need a new belt, 4Bar fuel regulator and a ECU remap.
This done your intake air temp will skyrocket when in boost so a supercharger poring will be needed and a bigger intercoller.

Apart from that YES. It's quite tempting. You always want more and more. :) :) :)

[John Jones Jr.]

84 mm is too small. Smallest you can go safely is 87 mm. Then you'll need a new belt, 4Bar fuel regulator and a ECU remap.
This done your intake air temp will skyrocket when in boost so a supercharger poring will be needed and a bigger intercoller.

Apart from that YES. It's quite tempting. You always want more and more. :) :) :)

Correct K-B my mistake, I think it's 94mm standard and then down to 87mm. What I was really more interested in doing was getting a custom inter cooler, not necessarily bigger, just better.

[John Jones Jr.]

Double post.

[KrumB]

Have a look at this:

http://www.benzworld.org/forums/r170-slk-class/1393510-intercooler-install.html

You can check Steve's other threads. Very interesting. :)

[John Jones Jr.]

Double post again!

[John Jones Jr.]

Thanks K-B. That intercooler upgrade looks very interesting and great valve, now for sale @ $85 + shipping + import duty - still very good value. My only reservation is, there's NO improved BHP or temp figures give on the thread. So, I have to ask is it worth doing? I suspect it is but presuming it has helped say by 5% just for this excerise, that's on an M45, so it would be even less on the cooler running M65.

Have you changed your I.C.?

[KrumB]

No but I'm about to next month.
Now I'm installing this:
http://www.benzworld.org/forums/r170-slk-class/1691134-my-intercooler-spray-video.html
http://www.benzworld.org/forums/r170-slk-class/1417229-intercooler-spray-testing.html
:)

[John Jones Jr.]

Good one. I did a bit of research on this before and seems very effective system. Will be interesting to hear how you get on. If you can do a write that would be really great.

[KrumB]

Sure I will. :)