jgsx

Quick background: My car was running fine until I had an intercooler leak. I replaced it, and at the same time noticed that my pulley damper was on the verge of giving out, so I replaced my pulley set. I have a EC 181 pulley.

After that repair, the car began disengaging the supercharger after a few moments of WOT. Eurocharged provided me a new flash with the torque limiter removed. After that, the car would stumble while under WOT, and give P0300 misfire and P0108 high map codes. Once I cleared those codes, the car would seem to pull back timing (although I didn't confirm this through logging) and would not have power under WOT. The SC didn't seem to be engaging. Resetting the ecu (battery disconnect) would repeat the cycle, where I'd get the P0300 and P0108, then the car would stop engaging the SC under WOT.

I use the car as a commute mule, so I continued driving, just without going full throttle. The car is a total slug under full throttle, but drives just fine part throttle.

Now the car doesn't seem to engage the SC at all under WOT. Even when I reset the ECU, it won't engage under full throttle. I don't get the P0300 or P0108 codes anymore.

What would cause my supercharger to disengage under boost / not engage? It's not my IC pump. The pump is fine and my IATs are low.

Here's a link to some logs. The SC did not engage in these. http://freepdfhosting.com/76434c52b9.pdf

Lenin

Are you using the OEM SC pulley? Is it gaped correctly? Is the wiring to the SC clutch in order?

jgsx

I am using the oem sc pulley. I assume the gap is OK but don't know how to check. What should I check for the wiring? You can see the car does engage to SC for a moment before disengaging, so I am assuming it is wired in.

Lenin

The gap between the clutch plate on the pulley and clutch should be 0.20-0.30mm. The simple way to check the wiring is to wiggle it. I would hold off on the more complicated check of the wiring. That would require connecting the harness to the electrical meter. One other thing to check is for any signs of belt slippage. Did you check for codes with the STAR system? Sometimes there are stored codes that need to be cleared.

Shamus964

I would go back and check everything disconnected for the IC swap including the MAP, IAT, vacuum lines, and the injector leads (esp since you're getting a misfire code). If you did spark plug wires while you were in there, check them also (they're a real bugger to seat).

Good luck!

jgsx

I did find a vacuum leak after I first saw misfires. I fixed that, and am not sure if that's the reason why they went away.

I reseated the SC wiring connector and made sure all the spark wires were snug. The SC still don't engage under WOT.

Is it normal to be able to "spin" the supercharger while the car is off, without the serpentine belt moving? Is this because the clutch isn't engaged while the car is off?

boohooramblers

Have you checked the fuse and relay modules?
Unlikely, but a possible cause.

jgsx

Where are the fuse/relay modules for this?

Pansu

Yes, its normal.

boohooramblers

I think there's one in each of the front and rear SAMs that are relevant to the supercharger and/or charge air cooler pump.

Here's a link with the relevant fuse and relay diagrams in pdf format.

I seem to remember some folks describing some variability in the location of some of their rear SAM fuses, so keep that in mind.

Also, I recall some users testing if their supercharger was working or not by applying an uninterrupted (bypass the relays) current to the supercharger (just something to keep in mind through the diagnostic process).

C32owner

Not sure if relevant to your case, and I am going back a few years now.. But I seem to remember having a similar issue as you with my car.. Turned out to be a water pump going bad if I recall correctly..

jgsx

boohoo - Thanks for the link. I checked all the relevant relays/fuses and they they were OK

c32owner - what was the water pump issue? Can you provide some more detail?


Thanks

vaiste001

Well known problem with C32. There is a water pump in the front passenger side that goes bad from time to time. Remove the passenger front wheel and the inside plastic fender and you will be able to see it. If you need a new one order using Bosch part number (0392022010) rather than OEM part. Much cheaper.

The pump circulates coolant underneath the supercharger and to the front heat exchanger. If the pump does not work no cooling takes place. IAT (intake air temperature) rises too fast and supercharger will not engage.

jgsx

Thanks Vaiste. I refer to to that as the supercharger intercooler pump. That's not the problem with my car. My IC pump is working, and my IATs are low. I attached that data in the PDF in my OP.

vaiste001

You checked the clutch gap with a feeler gauge?

Since you are getting codes the best solution could be to get a STAR connected to your car with a competent mechanic and using STAR to verify that all sensor readings are in acceptable ranges before randomly changing any parts. By this I mean connecting STAR to the car and driving along so that the mechanic can see all the sensor readings. Diagnostic devices are there for a purpose. Could be much cheaper than changing part randomly.

Newzchspy

Go see Marcin at Speedriven in Palatine, he'll cure what ails ya!!

Lenin

+1.

Velociabstract

I'm thinking it's something real simple like checking that the clutch's electrical connection is securely plugged in. Stranger things have happened.

Les

jgsx

I verified that the pulley gap is correct with a feeler gauge. I also disconnected and reconnected the clutch wire.

I asked my mechanic to look at it during my last normal maintenance. He says the car is overboosting. He though the car was getting too must boost, so it was disengaging the SC as soon as it saw that. It sounds feasible, but I have no idea why I'd be overboosting. I'm using a 181 pulley set. As a reminder, this problem started after changing a leaky intercooler and pulley set with a damper on its way out.

In the data logs that I posted (see my first post link), it doesn't look like I'm overboosting, but the sample rate on that CarChip logger is so low, it could be happening and the CarChip not recording it.

Any more ideas?

C3Duece

Im not buying the over boosting diagnosis being caused by the pulley. How many 181 pulleys have been sold with no mention of this problem? How would the vendors make any money selling kits that'd caused the SC to disengage.

If it is overboosting its probably due to a restriction somewhere...where did you get the I/C from? Maybe it's not allowing the air to flow?

Lenin

If your car was overboosting, you would get a P0238 code. I get it sometimes at the track, but only at the track. And maybe once out of 30 runs. Get a different mechanic. Take the car to Marcin.

jgsx

Thanks for the recommendations to see the guys at Speedriven. I wish I realized there was a pro shop in the area a long time ago. In short, my car had a handful of problems and Speedriven took care of all of them. My car is running like a champ again.

Just in case anyone is wondering, here's what happened:
-Problem started after replacing leaking IC and pulleys with bad damper
-Car wouldn't hold boost afterwards

I had my local Chicago Benz shop replace the IC and pulleys. They kinda screwed up. They aren't a speed shop, but I figured this was fairly stright forward work.

Problems were:
-Reused gaskets. Minor leaks
-Broken fuel injector. Bigger leak
-Silicon sealant used. Got into supercharger and added major resistance to moving elements
-Damaged super charger pulley/clutch. Probably from the added resistance

Replaced the injector, new gaskets, some TLC cleaning the supercharger and smoothing the clutch, and a new SC pulley did the trick.

Speedriven1

Lenin

Speedriven1

It was bad