Hi. recently my 1989 300e fails to fire on the first try. I have to re-turn the key a second time before the engine will fire and the car starts. what is the cause of this problem? is it the spark plugs or the injectors? i just had my battery changed 2 months ago, and about 4 months ago my fuel pump relay and idle air stick were replaced as well. please help....thanks

ben

Do a search for "hard start".

If engine is cold (first thing in the morning kind of thing) it could be faulty cold start valve. If engine is warm (parked for 15/20 minutes) it could be a faulty fuel accumulator located next to the fuel pump. Some of the techs here have also talked about a leak down problem do a search for the details.

I have never replaced a cold start valve on a 300E. Usually it is a fuel leakdown problem or a problem with the static ride height of the air plate.

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Benzmac:
Donnie Drummonds
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I was experiencing the same problem. A couple of days later (warmer days) my wife began to smell fumes. Then, suddenly the vehicle became difficult to start. Once it started it ran pretty well but the mileage dropped drastically....leaking fuel line coming off the filter. Few bucks later it fires perfectly and the possibility of watching all go up in smoke is vanquished.

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'89 300E 3.0
'82 350SD

Could be as simple as worn ignition system components - spark plugs, distributor cap and rotor. Over time the current transfer surfaces in the cap and rotor develop scoring and pitting, reducing the voltage that is delivered to the spark plugs. If the cap and rotor have over 30K miles on them, pull and inspect; invariably they'll need renewal. As for the plugs, I believe M-B calls for inspection/renewal every 15K miles.

I experienced a similar problem. Replacing the fuel pump relay helped little. Replacing the fuel pump check valves helped some. Replacing the fuel pressure accumulator did nothing. Replacing the injectors helped a lot. I did replace the ignition components first. I checked the air plate static height. It seems to be about 2 or 3 mm below the top of the throat, difinitely not too high (I don't think). I still get the problem rarely when the coolant temp is above 60C and the car has sit for 1 to 2 hours.

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Bob Johnston
87 300E