2003 C240 Periodically will not start
12-05-2017, 05:15 PM
#1
Junior Member
Thread Starter
2003 C240 Periodically will not start
My 2003 C240 wagon has started to have an issue where it will not start. If I wait ten minutes, it is fine. I had the battery and alternator checked, and took it to the garage and asked them to really go over it to find any possible culprits. They found nothing. Does anyone know what the possible cause might be?
12-05-2017, 05:46 PM
#3
Junior Member
Thread Starter
Cranks and cranks...generally starts to run, but feebly. This has now happened twice - each time I had driven the car, gone inside to run an errand, and come out to a car that won’t start.
12-05-2017, 05:48 PM
#4
Junior Member
Thread Starter
The fuel pump was replaced within the last six months - the one they installed died within five miles of driving. The garage claimed the part was bad - they replaced it and I haven’t had an issue. I am not sure if this is related.
12-05-2017, 06:20 PM
#5
Super Member
more than likely, the crankshaft position sensor is the culprit.. pretty common failure for those engines and under those conditions.. Reasonably cheap if you can do the repairs yourself, otherwise you will be out about 2-300 for the repair somewhere.
The following users liked this post:
Brianbanion (12-05-2017)
12-08-2017, 08:36 AM
#7
Junior Member
Thread Starter
It has happened a total of three times at this point. The check engine light came on the second time only, and went off within the day. I have not retrieved any codes. I am replacing the crank position sensor today to see if that is the culprit.
Trending Topics
12-08-2017, 12:04 PM
#8
Get a fuel pressure gauge and hook it up to the fuel rail on your engine. Turn the key to position 2 (just before cranking). You should see beween 54-61psi even. Start the engine. Fuel pressure should remain in that range even when you rev the engine. Anything less and either your fuel pump or fuel pressure regulator (built into the fuel filter) is bad.
http://www.mercedesmedic.com/fuel-sy...hooting-guide/
I just replaced both on my C320 wagon and its running well again.
http://www.mercedesmedic.com/fuel-sy...hooting-guide/
I just replaced both on my C320 wagon and its running well again.
01-05-2018, 02:43 PM
#9
Junior Member
Thread Starter
Update - replaced Crank Position Sensor and had no issues for a couple of weeks, but then again this was an incredibly intermittent issue to begin with. Starting difficulties are back, and less intermittent in nature. Headed to have the fuel pressure checked, and decided to look under the hood when it wouldn’t start. I noticed a sound and wanted to report it in case it is of any value.
When I turn the key on, there is a sound which seems to be on the passenger side of the dash - you can hear it inside the car. It sounds like a very small motor running. When that sound stops, there is a faint, high pitch which you can only hear from outside with the hood up. It is difficult to pinpoint its location, but is seems to be coming from behind the engine.
As soon as it starts, I will go have the fuel pressure tested and will have more information on that front.
When I turn the key on, there is a sound which seems to be on the passenger side of the dash - you can hear it inside the car. It sounds like a very small motor running. When that sound stops, there is a faint, high pitch which you can only hear from outside with the hood up. It is difficult to pinpoint its location, but is seems to be coming from behind the engine.
As soon as it starts, I will go have the fuel pressure tested and will have more information on that front.
01-06-2018, 11:41 AM
#10
Junior Member
Thread Starter
Tested fuel pressure and got two results: 55 PSI with key on, and the same when running. It held steady, with no fluctuation. I turned the car off and tested again. Zero fuel pressure with the key on, and obviously it wouldn’t start.
Any theories?
Any theories?
01-06-2018, 04:53 PM
#12
Super Member
Brian, check for voltage at the fuel pump.
Fuel pumps go bad all the time. They often go intermittently bad, or intermittently weak, before they fail completely.
This is true for all fuel pumps in all vehicles.
If there isn't any voltage at the fuel pump, look for voltage at the fuel pump relay. Those also go bad.
Fwiw, I do not know if the C240 has the "two fuel pumps" that are in a number of MBs.
Fuel pumps go bad all the time. They often go intermittently bad, or intermittently weak, before they fail completely.
This is true for all fuel pumps in all vehicles.
If there isn't any voltage at the fuel pump, look for voltage at the fuel pump relay. Those also go bad.
Fwiw, I do not know if the C240 has the "two fuel pumps" that are in a number of MBs.
01-06-2018, 05:35 PM
#13
Junior Member
Thread Starter
I already replaced the relay before getting to the filter. The fuel pump that is in the car is less than a year old.
I just changed the fuel filter, and was unable to get a bad pressure reading after. Gonna take a drive and see if I get stranded.
I just changed the fuel filter, and was unable to get a bad pressure reading after. Gonna take a drive and see if I get stranded.
01-07-2018, 02:32 AM
#14
MBWorld Fanatic!
Drive it with fuel gauge attached, I have also seen poor connections at the fuel pump plug under the seat, inspect them carefully. Maybe fit a volt meter at the pump plug too, when it cuts you can see if voltage drops.. just remember that about 1 sec after the motor stops the relay wil switch off. So watch carefully what happens first
The following users liked this post:
Brianbanion (01-10-2018)
01-08-2018, 03:12 PM
#15
Junior Member
Thread Starter
I took the car to a garage and it has been diagnosed with a faulty Fuel Sending Unit. They told me that the part costs over $1800, but I find it for much less on line. Am I being fleeced?
Also, it seems like a SIMPLE repair.
Also, it seems like a SIMPLE repair.
01-08-2018, 04:05 PM
#16
MBWorld Fanatic!
I did mine with an OE replacement for 450. I bet they want to do both sides and labor added sounds a little hefty but not a complete ripoff. they are likely marking the parts up also. It is a pretty easy job if you are handy.
The following users liked this post:
Brianbanion (01-10-2018)
01-09-2018, 07:08 AM
#18
Junior Member
Thread Starter
The $1800 was just for the PART, and not for both sides - this was for the Driver Side Fuel Sender. I told them I would do it myself. I ordered a Bosch Fuel Sender for under $300. I hope this fixes the issue.
01-09-2018, 08:21 AM
#19
Junior Member
Thread Starter
01-09-2018, 08:58 AM
#20
MBWorld Fanatic!
I have never had one fail on me. They just crack and leak gas into the back seat.
01-09-2018, 09:38 AM
#21
MBWorld Fanatic!
He is talking nonsense, you don't need a fuel sender at all to make the car run, long as there is fuel in the tank the pump will function! He is replacing the complete pump and sensor as a package I would imagine.
01-09-2018, 09:50 AM
#22
Junior Member
Thread Starter
I asked specifically if he was replacing them as a package and was told no. This mechanic replaced the fuel pump less than a year ago, and it failed that same day, and was replaced again.
Nothing I read would indicate that the fuel sender does anything but measure the amount of fuel in the tank.
01-09-2018, 09:56 AM
#23
Junior Member
Thread Starter
Is it possible that fuel is not getting from the drivers side of the tank to the passenger side? Is this a function of the sender or solely the pump?
01-09-2018, 10:26 AM
#24
Junior Member
Thread Starter
“THE FUEL SENDING UNIT AS THEY CALL IT DOES MORE THAN JUST SEND A SIGNAL TO THE FUEL GAUGE . IT CONTROLS THE FUEL PUMP YOU COULD SAY .” This is from this thread http://www.benzworld.org/forums/w203...em-solved.html
01-09-2018, 11:20 AM
#25
MBWorld Fanatic!
The fuel pump assembly consists of a pump a sender and fittings for the pipes. fuel that returns pressureless on the return side enters the left half of the tank where it helps to syphon fuel to the right side of the tank where it fills the delivery bowl where the pump fits into. So long as the pump can produce sufficient pressure the delivery system will function from left to right half of the tank. It has no moving parts so it can never wear out, so long as your pipes in the tanks are leaktight and rubber seals are good. You then have 2 fuel sender units which measure the volume of fuel in each half these values are then read in by the rear Sam, added together and transmitted to the cluster. Level sensors will NOT effect fuel delivery at all.
The following users liked this post:
Brianbanion (01-10-2018)
