2003 E320 cranks but won't start...
 

Drove to a fast food place, parked and ate... when I went to leave the car only cranked but wouldn't start. I was able to start with the gas pedal to the floor but it was sputtering. I let go of the gas pedal and it died immediately. Towed it home and read that the CPS "C" for "Crank" not "Camshaft" could be the problem so I replaced it. The car still cranked like before but just wouldn't start. Now I'm trying to decide if I should replace the fuel pump or the camshaft position sensor. I checked all fuses and both batteries power and they all were fine. Any suggestions would be much appreciated. Thank you.

I'll save you the wrath of Plutoe...

At the very least you need to find an OBD-II code scanner and find out if there are any trouble codes stored. At the BEST, you need to find a dealer or someone with Star Xentry diagnostics that can properly do a full quick test on all the modules. The OBD-II scanner can only give you diagnostic codes that relate to emissions control, so it may be totally clear, which is why the Xentry scan is better.

It can be very frustrating and expensive to start throwing parts in, without at least a good idea of where to begin. If you can rule out obvious things like "no voltage at fuel pump when cranking" then you might get lucky - but the Xentry quick test is the best way to go.

^ Get the codes and fix what is wrong. Guessing cost way too much money.

Change it? Changed the Crank? or CPS? No codes?

I have the CPS (Camshaft Position Sensor) and still continue to crank but not start. I then kept reading another online posting about the same issue. What I discovered was it could be the fuel pump and or the fuel pump relay. I tested the relay and it seem to be in working, so I test to see if power was going to the fuel pump and it was so I check to see if I could hear the fuel pump power up and make a sound which it didn't. I went on eBay bought a fuel pump for $100 bucks removed my fuel pump and replace it with the new aftermarket one and once I put everything back together it started up perfectly. God only knows and probably a few of you here how much money I saved! CPS $50 Fuel Pump $100 total repair cost = $150

Thank you for the help.

Hey MarkSilva Its funny you mentioned this subject! My son has been driving my wife's '03 320 for the last two weeks since his is in the shop. He said THIS morning when he stopped for hot chocolate on his way to work (40 miles away) the car wouldn't start when he got back in. He said he waited about 30mins before it would start. At first we thought it was just a glitch a one time thing,then he said this evening when he stopped for gas it did it again except this time he pressed on the gas pedal a couple of times thinking he was priming the fuel pump and it started!. Now reading your post I think I see where this is going. My question is how hard was it to change the pump and exactly where is the pump located? I am mechanically inclined a little so I'm not afraid to do it myself. Thanks :y

im having the same problem with a customers car. replaced the fuel pump, fuel pump relay, crank position sensor and the car still cranks but still wont start. anyone have any advice?

The Hall effect sensor that picks up the pulse wave from the tooth gear and sends the signal to the central processor to determine if the engine is running to keep the fuel pump by powering the fuel pump relay and also providing the signal to the system when to fire the spark.

fuel pump relay, fuel pump keeps burning out
 

I had a similar problem where the car would crank and no start.
Found the problem, no fuel reaching the injectors. Found a bad relay. Replaced it and the car run for 2-3 times and then same problem. Now I found the fuel pump was gone. Replaced it and the filter. It lasted for 2-3 starts. Again fuel pump died. New replacement and same results.
Any suggestions????:smash: