DimitriosT

So this is the story I bought this 2004 c240 with 90k miles on it good condition and all but it has a problem. It cranks and goes to start sputter than a loud pop sound from engine area almost like a backfire then dies. The previous owner said that one day he went to start it and it would turn over start to run and misfire and just die so he changed all coil packs and installed new Bosch plugs and the problem continued also changed maf. I've been reading alot of posts and doing research so I started my troubleshooting.
I have a Mbii scanner tool
got codes p0302,p0300,p0305,p0306,p0304,p0102,p0112
most of them misfires and the other last two maf.
so I cleared them.
first problem i found was one of the coil packs the a and b wires were reversed so I put it where they supposed to be
Second problem checked fuel pump relay it was not clicking when I tested it so i replaced it. Pulled the back seat and checked fuel pump and it was working saw the fuel pump running when ignition on. Then checked the fuel pressure on the rail was getting 50psi then when I go to crank it goes up a little more. Funny thing is that when I changed that relay the car seemed to run just a little bit longer but did the same thing just shut off and a popping misfire sound again.
now I just ordered a cps and a fuel filter I don't know what else could it be I'm kinda stumped. I'll change the cps first and see if that does anything I'll report back but if not I don't know where to go from here. Has no codes now either.

DimitriosT

I changed the crankshaft position sensor wow what a pain in the butt well for me with my hands...but it didn't fix anything still cranks then starts then dies I don't know if I'm overlooking something but I was looking over vacuum lines to see if anything is disconnected I didn't find anything. could it be the the whole intake manifold that is bad or cracked somewhere that's causing this? Has anyone else had same thing happen? Any information will be much appreciated thanks

DimitriosT

I did a little more investigating with a flashlight all around and found a chunk of aluminum in front of the intake manifold was missing on the passenger side. then I saw where that black little thing that has a linkage that connects to some kind of lever is cracked where the lever connects to the intake manifold all around like a circle so when u take a screwdriver u can actually see the inside of the intake so I guess that's a big problem. How the heck can something like this happen the rest of the intake manifold looks like brand new but the front has 2 circular holes.

Cracked right where those circles are

DimitriosT

So far as an update I went to a local u pull it yard and found a 2004 c240 wagon there with the parts I need ...I got the intake manifold egr valve throttle body and maf off of it I was like might as well take it all... I ordered new gaskets for the intake manifold and egr valve and throttle body from fcp euro cleaned the throttle body and egr valve and I gotta try to clean the throttle body somewhat because of some oil residue but the parts look pretty good. Now I gotta be careful taking the throttle body off my car because the junk yards you just Rip **** out. I will attempt doing this tomorrow looks prettystraight forward hopefully no wires or vacuum lines get messed up....I need to know what is the torque specs on the throttle body when I put bolts back on wish me luck

DimitriosT

Look at what i pulled out how the heck did this happen


well I replaced the intake manifold successfully and the vehicle started and is running now but I'm getting misfires on cylinders 3 4 and 5 I gotta find out what's causing them. Started it again and only 4 and 5 misfiring now gotta check coils plugs and maybe fuel injectors hopefully it's not a clogged cat.....

Fathur

so i like tO know more about the missfire, my car had a vibration when moving with the rpm 1,5k thru 2k and goes smooth after that rpm are those can be consider to be a misfire or not and my car may have a fuel cons problem, my avg fuel cons 16.7l/100 km is that kinda normal or not. (C240 m112 2005) thanks

DimitriosT

The way I checked for misfires I have a mb11 from carsoft it has a fault option and it tells you how many times the cylinder misfires while running I'm still trying to figure out what's wrong now I'm getting multiple misfires on cylinder 2 and 5 when I find out why I will post it could be gas fuel injection problem or spark hopefully nothing else....