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1993 300SE Overvoltage protectin relay?

2K views 9 replies 5 participants last post by  96H 
#1 ·
Does anyone know if my 93 W140 300SE has an overvoltage protection relay? If so, where is it?

Thanks!!!
 
#4 ·
Thank you! I'm chasing a pain in the a$$ of an issue. Starts and runs cold, but runs like crap, or not at all, when warmed up. Then won't restart until it's dead cold. Seems like it's a fuel & spark issue. I was told to check the fuse on the OVP relay, if it had one. I suppose these fuses would/could have the same effect?

Thanks again!
 
#5 ·
If one of those fuses are blown, then you'd have more drastic issues since it'd mean one of those modules simply would not have power and do it's job, like the fuel injection module. A blown fuse doesn't get better when cold. Check them by all means, since they control so much, but I doubt you'll find one of them broken.

Since you have a 1993, you may want to check the distributor cap and rotor. It's often pointed that these parts cause this kind of issue when moisture or oil is getting into them.

Another issue maybe that your coil pack needs to be replaced.
 
#6 ·
List of parts I have changed: Cap, Rotor, Wires, plugs, MAF sensor, throttle body, fuel filter, both fuel pumps. Grabbed a spare coil I had around the garage & hooked that up because the spark seemed weak, no dice. Checked voltage to the coil, seems to be intermittent, not steady 12v. Ready to just run a jumper from Battery to positive on coil to check.
 
#7 ·
Looks like you've gone through everything anyone has ever suggested on this forum. :p

Might be a faulty crankshaft sensor though.

You may simply have to check every sensor's physical condition under the hood. Check for corrosion in the plugs, lose connections, things like that. I'm going to be doing much of the same on my car's ADS system since it's acting faulty with no codes.
 
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