Hard-Starting 1992 300E
 

My '92 300E has been having an intermittent cold-starting problem. Sometimes it will take up to 2 to 3 minutes, or even more, of cranking to fire up. Once it does turnover it's fine. I'm not sure yet, but it may have a correlation with wet weather. I replaced the OVR and that hasn't helped. Any thoughts or ideas? The car runs fine.

test
 

test

Re: test
 

That's just it! TEST!

Don't throw parts at the problem! The OVP failure is symptomatic of a WARM start problem, not cold. You may have dodged a bullet by replacing it if it was on its way out.

Methodically check ignition points, plugs, coil, etc. Then move to the fuel system components.

I will fathom a guess that the fuel pressure regulator is at fault. But again that is just a guess, so don't run out and replace it!

Go through the engine systematically, and the ailing part will show itself to be the fault...

Hard Start
 

Thank you, G-Benz, for your input. Based on your response, can I assume that cold-start problems can be caused by electrical problems? I guess if the sparking system is weakened just enough, it won't fire the engine; but when the engine is warm, the added heat in the block helps ignite the fuel...something like that?

I know moist weather can affect the performance of electrical components as well. You may have a bad ignition coil (there are three?).

Start your diagnostics there...

The 92 300E's were the last year that used the 3.0 liter M103 engine, so they have a distributor, with one coil wire and 6 spark plug wires.

Hard Start
 

Thank you Suginami!

Which components would you start with, if you were in my shoes? Again, I'v already replaced the OVP -- no change. the car takes a long time to turn over when cold (and I do think air temperature and humidity play a role). Runs fine once it turns over. Warm starts are not an issue.

I would start by making sure the ignition system is top notch.
Spark Plugs, distributor cap, rotor, ignition wires.. I'd check the coil at the same time and maybe a compression check while the plugs are out.
If this does not solve the problem, I'd go to the fuel system:
Fuel accumulator,check valve and filter, good time to check the fuel pump pressure/volume output.
If all this is in top condition you've covered most of the cause of hard cold start.
The cold start valve could also be deffective, but this valve only operates below a certain temperature (I think below 49deg, but not totally sure about that.)
JackD

Hard Starting Solved
 

I replaced the coil and that took care of the problem! Thanks all for your help.