Hi all,

New here and this is my first post so apologies in advance if my issue has been well documented before, I have searched thoroughly online though and cannot find an obvious answer/solution.

As a long time BMW M car owner this is my first delve into the AMG world. Just purchased an 02’ C32 which was advertised as having the below:

“65mm pulley, 185mm pulley kit - Needswings Pulley Saver Kit - PLM Heat Exchanger - SL55 intakes with K&N filters - Resonator delete - 2nd cat delete - Primary cats have been replaced with highflow cats - Iridium Plugs - Magnacor KV85 wires - Tuned by Euro Charged with 185 pulley, pulley saver kit.”

My problem is the car runs like crap and bogs/misfires on multiple cylinders when you give it even half throttle. Multiple misfire codes in addition to P0108 - Manifold Absolute Pressure/Barometric Pressure Circuit High Input. Which is throwing the CEL light. I need to get the problem fixed primarily so no damage is caused and I can enjoy the car, but secondly because I can’t get the thing smog’d running like this.

I am assuming (could well be incorrectly) that the 185 pulley is causing the over boost issues and the MAP is shutting down the charger, or something to that effect. From research I have also read that it could be a fuel flow problem.

Not sure where to start with trying to correctly diagnose and fix this issue so any advice or knowledge would be greatly appreciated. I am very mechanically inclined and know my M’s inside out, this is a whole new beast though and I am inexperienced with its mods.

What are the other codes? What color is the exhaust? Have you inspected the plugs? I would think that if its bogging on tip-in there's a vac leak somewhere.

Hi thanks for the response, I cleared the codes last night and haven't driven it since so no codes stored at the moment. I'll have to check if the misfires are all on one side or not. the P0108 code is the one that's worrying me though. Just looking for some advice before I start pulling all the plugs and dumping $ into replacing them plus the MAP and fuel filter etc as I don't think it's something that obvious/simple given all the mods on it. That said I hope it is Will check exhaust tomorrow in daylight but didn't notice anything out of the ordinary while I was under the hood and under the car.

Thanks again

you're at the point where you need to start swapping in new parts. I'd start it up and pull the codes again and get the exact cyl #'s that are reporting. start replacing plugs, wires the coilpacks in that order. If none of that works you may need to familiarize yourself with this thread

https://mbworld.org/forums/c32-amg-c...-misfires.html


The over boost fault is something you should normally only see while the pedal is on the floor. The fact it's doing it now may indicate a bad map sensor/harness.

It could be the combination of the 185 mm crank pulley and the 65 mm SC. There were a lot of problems before they got a pulley combination to work. Especially if the tune isn't perfectly matched to the set up. For a long time dual pulleys was a no no. If the guy you bought the car off of gave you the old pulleys, I might try putting the OEM SC pulley on with the 185 (or the other way around) and see if that solves your problem. The SC pulley is an easy swap.

Unfortunately the guy I bought the car from was not mechanically inclined at all. He in turn bought the car already mod'd from someone else. So I have no background or paperwork on the mods. Ok pulling plugs and wires today, conducting leak down test, no original pulley's on hand. However if other checks pass then will go for an OE size SC pulley as suggested. Fingers crossed it's not camshaft or cylinder issues.

Thank you both for your advice and suggestions, very much appreciated.

You should not run 185mm crank pulley with the 65mm SC pulley. Way too much boost and may be not enough fuel. Hopefully no permanent damage was done. Figure out what setup you want to run first, bring back the car to that level and then start troubleshooting, if needed.

Check the coil packs too. I've had a few of them go over the years.

Hi guys, so compression is good, anyone know where I can get a stock size 73.6mm SC pulley to replace the 65mm? Best price I've found so far is $475. Seems a bit steep for a stock pulley!!!!! Anyone know of a better price? Thanks

What is the spark plug gap? If it is too big you have misfires with high boost. You should try 0.6-0.7mm. And if plugs are too cold, that can also makes problems.

And that P108 comes with high boost, i have same issue. It must be some kind of program issue and EC try to fix my problem, but not succesful result...

And you are running a 168mm crank pulley and a 65mm SC?

Yes something like that, EC fake 62mm aluminium pulley(witch is about 64mm in real) and crank is about 168mm if i remember correct.

Code comes somewhere over 1.3bar boost(it goes pending codes), and when it repeat several times then CEL goes on. I now have ~1.5bar max boost in those pulleys.