chakapat

Hey guys, ive been lurking around this forum to figure out what is causing my car not to start but havent had any luck.

I purchased a used 04 c320 sport sedan 6 speed manual transmission last month. It drove fine when I took it home but the following day it didnt start. Found out that it was due to a dead battery and got it replaced. Immediately after I installed the battery I tried starting it up and it didnt start but after waiting a few minutes I tried again and was successful. I took the car to O reillys(where I purchased the battery) and had the voltage of the battery, starter and alternator checked out. Everything was fine. The next couple days the car would randomly start(weird) so I thought it was due to the seat drainage issue. Just to be sure I took it to a mercedes dealership for a diagnostic check(luckily this was one of the days I was able to start the car). Picked up the car 2 days later and was told that there was NO PROBLEM! So I drove it home thinking maybe whatever was causing my car not to start had magically disappeared. Nope. So fast forward to today and I am still having the same problem.

What I can tell as of now is this. I notice the LCD display on my car is significantly brighter during early morning and late night. I am also able to start the car during these times. When its sometime during the afternoon(4-5pm, usually when I get off work) half of the LCD display is extremely faded and the car will not start. I know this sounds strange but Im guessing it might have to do with the external temperature of the car. The car is never parked under shade(no shade on my street).

So I was wondering if anyone has been through this before or any info on what I can do to fix it. Thanks for taking the time to read my post!

hanknum

Sorry, I don't have any suggestions for you. But, thought it was cool you have a C320 with a 6 speed. I think that combo is kind of rare. Where abouts are you?

chakapat

Yea I hear these are hard to come by and I'm glad I was able to get it but i haven't been able to enjoy it because of this problem. Looks like we're both from the same area, so cal!

neurodave

LCD display is known to dim. They degrade over time and start to burn out in the heat. Mine looks perfect on cool nights or days, but when it's hot out or has been sitting in the sunlight for too long, it fades. You have to replace the LCD screen in the speedo to fix it.

As for the random starting, I am having the same issue. Mine will start fine for about a week or so, and then randomly start having issues. Sometimes it starts after a second try, on rare occasions it takes 5+ times to get it on, but fires right up when it does. It's a hit or miss on when it happens. I thought heat might be the culprit (which might lead to the crankshaft sensor, that I already replaced) but lately, it hasn't mattered if the car is cold or not.

My next stop is a shop to have it diagnosed. I've had people tell me it could be fuse 52 isn't the 20 amp, but rather the 15. I've read it could be the fuel filter. I even had an MB dealership suggest that the crankshaft sensor I installed wasn't OEM (which it isn't, I got it at AutoZone) which seems plausible seeing as these cars are picky.

Start with the easiest culprits (and cheapest) and work your way up.

krazzdav

CPS?? Mine was intermittent but really only shut off or not start when the engine got warm rather than from a cold start like yours.

Does your car crank but not start or does it not even crank/turn over? If it cranks but no start could be the CPS. Its cheap enough to replace just a pain to get to and need some long 1/4" extensions with a universal joint to get to the bolt holding it. I did mine in a Sears parking lot since it wouldn't start after getting the extensions. :P lol

If it doesn't even crank it is something else....

chakapat

@Neurodave and krazzdav, Thanks for your replies! I just bought a CPS off amazon and watched a tutorial on how to replace it online. It does seem like a pain in the *** to replace but its better than paying 400+ at the dealership. Im guessing that its most likely the CPS since it reacts with the external temperature and may prevent starting the car. My car does crank and itll start after 5+ attempts. Will provide an update. thanks again!