86' 300E hard starting when cold
 

Hi everyone!

I have been on this mission for the past week so far to determine why my 86' 300E has trouble starting in the morning or any other time the engine is cold. It has to crank for 2-3 seconds before starting but it seems that when it has been driven recently and I go to restart it has no problem.

So far I have checked the fuse in the OVP, it looked good, but I replaced it anyway. That hasn't helped my problem.

My question is what do I check next- cold start valve, engine temp sensor, fuel accumulator, etc? Also how do I check these items, I have heard most of them are fairly mild DIY obstacles, I simply need to know where they are located. Any suggestions would be greatly appreciated.

BTW, I tried leaving the key in the "on" position for 5 seconds before cranking it when cold, that did nothing. Also, I do hear the fuel pump buzz for a brief moment every time before I fully turn the key to start. And the car is always garaged at night in middle temperature weather typical of Southern California.

Thanks,

Jerry

The list of possibilities is endless. The SEARCH facility here will prove useful. Hard starting 103 motors has been kicked around a kazillion times.

How old are the spark plugs, spark plug resistor tips, rotor, cap, etc. ??

Mike,

Yeah I have been using the search it seems like all week and I have printed over 20 threads that pertain.

The spark plugs are less than 10K miles old but as far as everything else is concerned, it hasn't been done since I owned the car (15K).

My question is which should I pick to troubleshoot first?

Thanks,

Jerry

Cold Start Problem
 

Did you get the problem solved? I'm having the same problem....

Well... the problem is sort of solved. I replaced the OVP just for the hell of it and now it starts cold with no problem. There is still just a slight hesitation (less than 1 second) but I figure that is to be expected with a car that is 16 years old.

Cold Start Problem
 

What is the OVP and how much effort (cost) is there behind replacing it?

OVP = overvoltage protection relay

It costs about $50 at any aftermarket retailer.

It is located behind the battery near the firewall. It has a fuse that mounts on top of the relay (or two fuses depending on which year). I am speaking with the experience from my 86' 300E. It takes less than 5 minutes to replace.

Cold Start Problem
 

Thanks!!! My battery blew up right before this started happening... so maybe they're related....?

Battery blew up?
 

You bet, they are related! I would also check the alternator/voltage regulator brushes...:cool: