hergs7

So my car was hard shifting and kicked out to neutral a couple of times - bought a trans dipstick and topped off fluid with 1 qt. Went for a short test drive and the car felt 100% better after topping off.

Same day as topping off the transmission fluid, the car died rolling into a stop sign a few hours later. No sputtering and all electrics still working fine. Tried a new CPS with no luck (it had been replaced recently already but matched the symptoms) and eventually after testing fuel pump and checking fuses and relays found that a fuel line on top of the pump wasnt staying connected because the plastic clip had lost its springiness. Found a suspicious metal twist tie in the bottom of the tank and temporarily remedied the clip with a zip tie. Fuel pressure was good and cranked right up no problem.

So now, car is running great, take it out for a test drive and I have no boost! So I go back and double check everything from doing the CPS and fuel stuff make sure I didn't accidentally unplug anything on the back side of the supercharger. Eventually found that the supercharger pulley bearing had let go so sourced another bearing and rebuilt the pulley. Got everything back together and still no boost! So got a OBD scanner and checked IATs, boost, etc and everything looks fine except I never reach boost. Doesn't matter if it's from a cold start or after running for awhile. No codes and nothing else I can find out of wack. Checked IC pump and its all good. Tore the entire supercharger off and chased all the wiring and bench tested the magnetic clutch and everything looks and works great. I'm pretty lost at this point. Reinstalled everything and crank back up and car is still running great but still no boost.

Mods -
Renntech ECU / TCU tune - bought the car this way, don't know who performed the tune
172MM Crank
550cc injectors
Johnson CM30 IC pump
Aluminum pulleys

Any help is greatly appreciated.

BlackHammer

Check out my response on this threat and keep us posted.

https://mbworld.org/forums/w211-amg/...ml#post6983298

hergs7

Everything fuel related seems to be working normally. I can go through the rpms just fine with no hesitation both driving and in park I just never see any boost. Fuel pressure stays high verified by analog gauge at the rail.

Does anyone have any info on how to test the bypass valve with the 6 pin connector? Keeping in mind I don't have access to star at this point.

BlackHammer

Only thing I can think of is the clamps on the surge tanks are loose or came off completely (?). My apologies if you have already did this troubleshooting step and I missed it.

Will be interesting to see what other folks suggest.

TK

hergs7

Surge tanks are clamps are secure. Hoping others will chime in as well

Forrest Gump 9

Try disconnect the battery for ten minutes. That's solved my no boost issues

BlackHammer

Guys come on. No Boost is like a lost pet; critical situation!

euro, Anthony, shardul, chawkins, hulk, jmb16, etc. you guys got nothing?????

210lvr

You can try to use a dmm and hook up to ME pin 2.3 and 2.4 for the recirculated air flap. Start car and note the voltage. Then drive the car and go WOT. See what change you get from the flap. This should let you know if the recirculated flap is actuating or if it's just staying open. Would be better with an oscilloscope or data logger but whatever, dmm should give you can idea.

hergs7

Thanks for the helpful info. I'll give it a try this afternoon. I have a data logger that can do the job.

WANTED!!

If it is staying open, is there a relearning procedure or is the only option to replace it? I'm looking in the WIS and I'm not finding one if there is.

Rocman8

Hook up to star to check for codes in other modules like esp and trans

jmb614

Unfortunately it sounds like you may need to hook it up to STAR to get further info. Or go the multimeter route as previously mentioned.

LandCruzer94

I spent all last night searching STAR in Sim mode for any semblance of a bypass valve relearning procedure and haven't found anything, unless it's buried in developer mode (and in German). The only other way I can imagine it happening is resetting all adaptations for the ecu (or default initializations, I can't remember), but I'm wondering if it will overwrite any custom tune that is loaded.

It's funny, because W203 chassis Kompressor models have this feature front and center in their menu.

WANTED!!

Exactly!!!! I have development mode and I'm not seeing it, which is passing me off. It's possible I'm stupid and just missing it, but this seems like it's something not offered on the w211.

That said, I'm also not boosting with no cells either. nothing stored on my ecu. I'm about to pull the trigger on another supercharger but would rather not if I don't have to.

jmb614

I've asked I think it wsa Rovveron in another thread about syncing the TB and bypass with STAR, as, iirc, he stated it could be done. As mentioned previously by Gump, pulling battery for 10 mins should reset the ECU, (wont remove tune). After reconnecting I would put the key in position 2 for 60 seconds+, that should at least get the TB to learn its open/shut positions and may do the same with the bypass, but as I mentioned, I have not been able to get confirmation.

There is likely a test in STAR for the bypass, but I am away from my STAR unit to check.

LandCruzer94

Probably the same thread I'm thinking of too, looking for the reset procedure for the 82mm TB hiccup but I'm sure it could apply here too.

hergs7

I'm trying my best not to replace the whole unit as well. I'll get a data logging done soon on the bypass. Can anyone tell me which pins are ME 2.3 and 2.4?

jmb614

Likely connector 2 pins 3/4

hergs7

that would make sense... for anyone else who may be looking pic below

JoeJErnst

I seem to remember the bypass valve and throttle body having the same plugs. If so, is it possible that they were plugged in to the wrong harness connectors? I remember being worried about this when I had my SC off but everything worked when I started it up so I never bothered to ask the question. Maybe now is a good time to know that answer.

hergs7

Thought about this when doing the initial checks. Swapped connectors and the car started and then immediately went into a very rough idle so I killed it within a second or so and switched them back.

seanol

Also the throttle body has blue tape on the harness, the bypass valve does not. Might be an easy way to verify quickly.

oneslow55

Check fuse for supercharger

hergs7

Which fuse?

oneslow55

40 amp fuse and the relay