j d0g

i have a 2002 e320 4matic. one day i got in to start the car and it would not crank over at all. this is the first time it had happened, i had to leave the car at the gas station overnight. i returned early the next day and it still wouldnt crank over. so i had planned to get it towed, i came back again late evening and it just started up randomly like nothing was ever wrong with it. so i drove for a day then parked in for a little while and then it wouldnt start again. its been doing this for a couple of days now. i do have a scanner that can get into every ecu, i found some codes in the transmission ECU, some said fault ecu and a communcation error with another ecu, but i cleared all the codes and got the car to start again but none of the codes came back. right now the car is starting fine, but i know that soon its not going to. i was wondering if anyone could help pin point this problem or what to check first. also wondering if the transmission computer would have anything to do with it not starting, before it did have oil in it but i cleaned it out and that was probably 6 months ago.

RichardM98

Hard to say but one possibility is the CPS (Crankshaft Position Sensor). It's at the back of the engine by the flywheel. As it starts to fail, the car will start if cold but not when hot.

j d0g

yeah that seems right, when the car was warmed up it didnt want to start, there was like a hissing/click when i was trying to start the car. ill drive it around and warm it up and test to see if it will start when it warms up. do you know of a way to test if the crankshaft is fault?

RichardM98

I think the dealer can tell if it is failing at the moment but maybe not if it is working. Intermittent problems are generally the hardest to diagnose. It's a pretty common repair on W210's. Many owners replace it themselves but you need a torx socket. Part is about ~$50.

003stars

Hi, bottom site showing something better than something? If you could use them.

http://losangeles.craigslist.org/wst...766064281.html

Won't last, just couple of days and good luck to you. 003Stars

j d0g

I talked to my dad who is and mechanic and my friends dad who is also a mechanic and they said to rule out the crankshaft position sensor, because even it was failing or failed the car would still be able to crank it just wouldn't start. but what I forgot to mention earlier is that my fuel pump is leaking but they said it shouldn't have anything to do with the cars starter not being able to crank. but who knows with these Mercedes. I guess what to check next is the connections going to starter see if its corroded or something?

hambone97

Car would only start on second try for a week. Went to dealer and they replaced the CPS . They rolled it out to me and I shut it off to show them something and went to crank again and it then only started on the second try. Took it home and went to YouTube and searched 'mercedes hard to start' and the answer was there. I went to the fuse box in engine compartment and pulled each fuse one at a time and cleaned the fuse blades with a cardboard nail file the women use. After finishing that, went to start it and it started on first try. Oxidation and corrosion in any electrical plug-in, relay, fuse, harness, etc. is going to interrupt the normal operations. Hitting potholes are jarring some of these oxidized connection and you get intermittents or failures of some operation. So get to cleaning first before the dealer does it for you for his price.