300CE starting issues - PeachParts Mercedes-Benz Forum

ohiomike · #1 01-05-2010, 02:56 PM

the fuel injection engine sensor is up on the front, top side of the engine block on the drivers side. I think the engine temperature sender in close by.

Ferdman · #2 01-06-2010, 06:33 AM

Fuel pump check valve sounds like a good start. If the fuel pumps run I would move on down the list of likely causes.

dubadaddy · #3 01-06-2010, 09:56 AM

Quote:

Originally Posted by ohiomike

the fuel injection engine sensor is up on the front, top side of the engine block on the drivers side. I think the engine temperature sender in close by.

Do you have a diagram or such for the location of these? My indie says that they are not there due to it being a CIS M104 engine.

Do you have any more specific info you can share??

73Elsinore · #4 01-06-2010, 02:30 PM

Could be fuel pump check valve or fuel pressure accumulator. Those are located at the fuel pump, at the rear of the car near the fuel tank. They do go bad as these cars age. Good cold starts but poor hot starts are a symptom of a failed accumulator. There is more info about this available on the web but I can't post it here out of deference to good form.

bsmuwk · #5 01-06-2010, 05:24 PM

Cap
Rotor

when was the last time they've been changed? i ask this, because it definitely sounds like heat increases resistance in the ignition system and you won't start with weak spark type of deal. another possibility is the crank sensor on the bellhousing. eventually they fail and you will NOT start period. without the crank sensor, you have no spark. pull the cap and rotor and check for corrosion. there is sealing o ring that seals the cap and rotor internals from moisture and this oring hardens and cracks over time with all the heat it is exposed to. when it's cracked, you'll have VERY bad corrosion on the terminals.

why have you narrowed it down to fuel injection? sure the accumulator could be a problem, but your car WILL start with a bad one, same for the check valve. you car doesn't start period, right? if the accum. and valve were bad the car will catch and stall a few times before eventually starting. you have to realize, it's HARD to diagnose with just words, you'll have a lot of ideas thrown at you with this problem, but start with the easiest and take a plan of action if something doesn't work out.

also, 4 seconds of cranking for a CIS M104 is considered NORMAL by MB. it may help applying 1/4 throttle at start up if cranking for a while.

i've went through the ENTIRE ignition and fuel injection system on my own 92 coupe. it was hell, lol. PREPARE!

dubadaddy · #6 01-07-2010, 10:18 AM

Quote:

Originally Posted by bsmuwk

Cap
Rotor

when was the last time they've been changed? i ask this, because it definitely sounds like heat increases resistance in the ignition system and you won't start with weak spark type of deal. another possibility is the crank sensor on the bellhousing. eventually they fail and you will NOT start period. without the crank sensor, you have no spark. pull the cap and rotor and check for corrosion. there is sealing o ring that seals the cap and rotor internals from moisture and this oring hardens and cracks over time with all the heat it is exposed to. when it's cracked, you'll have VERY bad corrosion on the terminals.

why have you narrowed it down to fuel injection? sure the accumulator could be a problem, but your car WILL start with a bad one, same for the check valve. you car doesn't start period, right? if the accum. and valve were bad the car will catch and stall a few times before eventually starting. you have to realize, it's HARD to diagnose with just words, you'll have a lot of ideas thrown at you with this problem, but start with the easiest and take a plan of action if something doesn't work out.

also, 4 seconds of cranking for a CIS M104 is considered NORMAL by MB. it may help applying 1/4 throttle at start up if cranking for a while.

i've went through the ENTIRE ignition and fuel injection system on my own 92 coupe. it was hell, lol. PREPARE!

Yeah, I not sure about the fuel injection problem myself but I figure I am going to try to replace the easy stuff first--fuel check valves-- as they don't cost alot.

I just replace the cap and rotor last summer and they should be good but I will re-check for a broken cap.

I will investigate the crankshaft sensor but I am not sure of the location. From what I have heard there is a sensor that is long and one that is short I will have to check it out as which one I have.

I love the car but I sounds like its going to be pricey to get the fuel accum replaced and to actually track down the problem without throwing a bunch of money at it. Being unemployed doesn't help either.