Hard Starting 1992 300E
 

1992 300E with 130,000 miles and M103 engine. Car takes a long cranking time when cold to start and will finally smooth out idle after about 30 seconds. Also starts a little hard after sitting a while when warm. Installed new injectors about 2000 miles ago, but suspect one or more of the injectors may not be working properly. How do you diagnose, without the special fuel pressure tools, which side of the fuel system may be the problem? I know there is a fuel accumulator next to the fuel pumps which keeps the fuel system primed after shutdown and the fuel injectors are supposed to keep fuel pressure on the other side of the injection system. How can you check the accumulator or the individual injectors to isolate the problems? Thanks for any help with this problem.

Check the condition of the distributor cap, distributor rotor, spark plugs and ignition wires. Spark plugs should be replaced every 30,000 miles.

Check spark plugs also for alot of yellowish-brownish deposits, sounds like bad valve stem seals to me, pretty common.
Gilly

Just replaced plugs, plug wires, distributor car and rotor at 115,000 miles. Good thoughts, though.

another thread fixed the problem by replacing fuel pump check valve, which I will look at concerning my 300E.

Plugs were changed 15,000 miles ago, right? 130,000 now, and were changed at 115,000?? Check the spark plugs.
Gilly

Bought car with 115,000 miles and replaced plugs at that time. Just pulled them out again and they are fine. Thanks!