my 89 300e has the worst problem right, its been taking like 5 long cranks to start some times not starting at all. I brought it to the mechanic that has done work to it in the pass and it sat there for 3 weeks and he told me it started first try every time. I got the car back yesterday and it was covered in snow and it was sitting there for atleast a week, when he fired it up it took about 6 seconds then started. I drove it all day yesterday then parked it at home. THis morning i went to start it and i drained the battery completely. It starts perfectly when its hot and its (-11) degrees celcius outside. This problem is pissing me off. I should add that about a year ago i was pushing the car hard and it died on me, it turned out to be the crank sensor, the sensor i have in now is used. you guys gotta help, please

P.S, cold start valve works perfect, Ovp fuse is fine and no warning lights are on

Its probably a combination of temperature sensor issues, and the idle control valve. Mine was doing the same thing till I worked my way through and replaced all of that stuff. Starts great at any temp now. There is a temperature sensor for the coolant at the back of the engine on top with a 4-pole connector....and also a sensor in the air intake, right on the side with a little cord coming off of it.

Also might want to verify that your "MAS" unit or fuel pump relays are working properly.

Using a "used" crank position sensor probably wasn't the best idea. They tend to fall apart after many years of hot/cold/junk going all over them.


How old are the: Spark plugs, distributor cap, rotor, wires, and coil? That can play a role too.

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hey thanks for replying, um the plugs and cap and rotor are about a year old and the car runs fine once its started. Its more about time theen it is about temperature like one time it was pretty hot out, the car sat for 8 hours and it gave me the same problem, it trys real hard to start, like sputters it just wont catch. Im not that fimiliar with testing all the sensors, can it be done with a regular multitester, what would you suggest i should check first

oh and the idle control valve was checked and cleaned too

Watch the mechanic start the car to see if there is something different in his technique than in yours (or to see if he is telling the truth about it starting first time, every time).

yeah yesterday i ran to see him start it, and it took about 7 seconds which still isnt right but it did start first try and it was completly covered in snow

its raining out right now and it doesn't even try to start. The last couple of days its been starting first try but rain really is worse, i checked the coil and its within spec so what should i look at now

A stab in the dark but a easy check. See if the ignition control mudule is getting a good ground, also move around the wire connections to the module there may be some corrosion

yeah i check the ignition module for corrosion or looseness and no go. The car is very moisture related though. It takes forever to start in the rain but starts fine on a sunny day and its consistent. My guess is Coil but its within spec and i don't wanna take a 200$ guess. Thanks for the reply but any other suggestions......

or if you want to start it quicker rev some gas, just a lil bit, clean the battery or get a new one, get all that acid out,

The battery is perfect, its one of those older interstate battery, strong as hell it turns over very strongly and for many cranks it just wont start the engine in those conditions listed above, so battery is out of the question, also playing with the gas pedal has no effect either

sounds fuel related to me. I would bet it is a fuel pump. A lot of times when they go out they will randomly start or not. I dont think the weather has anything to do with it. Make sure you hear the fule pump with the ignition in the on position.

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1998 E320 150,000
1980 300SD 240,000
1965 190D 79,000

Allen, if you're satisfied that the main ignition components (plugs, wires, cap/rotor) are new and working properly, your symptoms seem fuel related. How long since new fuel and air filters? Test pump, pump relay, fuel accumulator. It may be cranking long to re-pressurize the system every time after it's been turned off.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

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