- Mar 16, 2012
Was wondering if anyone had any ideas on why the supercharger wouldn't engage ??
Hi could be a number of things but when my w202 230k wouldn't it was because the maf was contaminated with oil! A good clean with contact cleaner and allowing to dry in the air it sorted it. Everyone will tell you don't clean maf but mine was only a year old so I gave it ago as didn't want to splash out on another new one and it's been fine ever since. Could also be bypass flap in airbox or kompressor cluch magnet gone. Best get it on a star to be sure but then again mine came up with airbox flap code but it wasn't that as I say it was maf. Worth taking maf out to see if it's covered in oil. If it is then oil is coming out of rocker breather into airbox so needs the two air jets under inlet manifold unblocking to prevent that, this is assuming yours is the m111 engine.Was wondering if anyone had any ideas on why the supercharger wouldn't engage ??
I've got a Bentley manual for mine but pics are poor. You need to remove inlet manifold just enough to access underneath so don't disconnect anything but iirc a few electric plugs, then hang manifold from bonnet with bungee or string. Under there are two rubber hoses maybe 10mm diameter. Unplug and there is two brass jets which are in head and go into inlet ports. There normally blocked! Also pipe will be brittle so worth getting new from merc. There is two that go to a non return valve into a larger one which iirc goes onto an air pump so you need new pipes from pump to jets and new valve. Was only £30 tops from merc. Trouble is if your going that route because oil contamination then all intercooler and pipes connected need cleaning out which can take 3 to 4 hours but worth it as mines been great since. Common problem on these engines according to the forum. But first check maf to see if it's covered. I did all mine and new maf but a year later had same problem as you but iam guessing oil was present still in kompressor as that's the only thing I didn't clean! Anyway I cleaned maf and all's been good for last 8months. Not saying this is your problem but a bit of insight and worth a look.Have you got any diagrams of the jets that maybe blocked? ??
Is is though? I'm unsure it is a common fault but maybe it is. According to the bit of research I did on inop & intermittent M62 S/C's fitted to M111's, the air flap rarely gets mentioned as the faulty part but of course it could fail and I'm sure some have.I suspect the recirculating air flap isn't moving, common fault.
You'll need to shop around as they vary in price, quality & make. I think I paid about €45 from eBay.de. This should be the correct part number for a FEBI BILSTEIN: 33737, but double check.How much are the sensors
Lets break this down one by one..
A couple of things from what has been mentioned on here so far.
When you cleaned your MAF was there oil on it dripping, or was it just a bit dirty but dry? If it was dry then you shouldn't have blocked breather nozzels on the inlet manfold so you can rule out having to do this job.
The SC should engage at about 1300 rpm. With the engine off look down on the left side of the engine and you will see the outer edge of the SC clutch wheel. Put some white paint or tip-ex so that you can identify easily when the engine is on and to see if it spins. Now with the engine rev the engine from the throttle cable on the right and if it engages it will start spinning at about 1300 rpm then off at idle.
IF it dosesn't spin then lets check the butterfly dump valve on your airbox. Undo the top jubilee clip and move rubber tube to the side, rev the engine and see if the flap moves. It will close when the revs reach 1300rpm and open at idle. This is what gives you the boost as the SC compressed air is forced back into the engine, then expelled when the flap is open just like a dump valve. If the flap is not functioning I would first suspect the MAF is faulty, as this directly links to the SC via the ECU and would rule this part out before continuing. You can try disconnecting the MAF but best to try and use a friends one and just plug it in to see. Do this first before moving on.
IF the MAF is good then go with what others have suggested, I bought a new air flap on ebay cheaply as mine blew along with a MOSFET inside my ECU when I floored it one day and blew an ignition coil ! I manged to fix my issue which was the SC always being on, rather then what you have is with not engaging at all. Fixed with the help of the forum and a steady hand with soldering !