I've had a problem with my 1987 300E with 260,000 miles starts and runs great cold. Once warm its difficult to start and barely runs. If I let it sit and cool down it starts right up and runs well.

I changed the Crank position sensor, coil and recently new Bosch O2 sensor (had a universal sensor installed and thought I finally solved this problem...but no.

After reading numerous posts seems like it may be EHA, temp sensor, OVP or fuel accumulator. Any advise on how to where to start besides replacing all these parts?

Thanks,
Dave

I would start off by checking the fuel accumulator. Poor hot starts are often resolved with its replacement.

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1989 300CE

ok - Thank-you!

If you have not already done a search, there are many threads on this topic here. What you will find is that the list of possible suspects is long: accumulator, check valves, OVP, fuel pump relay, EHA, temp sensor, pressure regulator, leaking injectors, and more. Get hold of the FSM and start doing the troubleshooting tests. Most of them are easily performed, requiring only a multi-meter and common tools. Good luck.

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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'

There are only 10 kinds of people in the world--those who understand binary and those who don't

You need fuel pressure gauges to test accumulator, although replacement is easy as pie. It's the simplest fuel component to remove from the package under the car.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Actually, you can test the accumulator by just removing the bleed hose from the backside (clamp it shut or fuel will run out it from the opposite direction).
Let the collected fuel run out of the accumulator, there should not be very much. Then crank the engine or turn on the ignition a couple times to charge the fuel system, and look for more drippage out the accumulator. If it does drip, the diaphragm is cracked and it's toast.
Of course, guages are much more elegant. Hook up the pressure gauge to the fuel inlet line at the fuel distributor and turn the ignition on ONCE. Pressure should zoom to 100 or above, and should hold quite high for some time. Best way to check everything ,though, is to hook the gauge to the plug in the upper chamber of the distributor, and then hit the ignition switch a couple times to run the pump. Pressure should jump to about 80, then drop off to below 50 when the pump stops. Should hold around 40 for some time, at least 30 minutes or so. If it drops pretty quick, then it's the accumulator, the check valve at the pump, injectors, or regulator.

Only way I remember all this is I checked mine Saturday.

DG