Hi,

My 1986 240DL has been running barely lately. I just replaced the engine harness because the little grey box up by the firewall was completely bare and all four wires were crossed. I understand one of those wires to be the oil pressure sensor and another to be the engine light, but what about the other two??

Could those wires have burnt out some part that I need??

Seems that the car is running rich.

A friend suggested that possibly there is a stuck valve what would those symptoms be?

Thanks..., almost there!

Oh, I also had to put new spark plugs in cause the old ones were really gapped (does the gap grow over time?)

And I removed the breather box, and flame trape and hoses and cleaned them all up.

Stuck valve symptoms include 1.) running really crappy because the cylinder can't build compression. 2.) if it's an intake valve stuck open you may hear compression being pushed backwards into the air intake system.

A simple thing to check or have checked by putting a compression gage into the spark plug hole and cranking the engine. If open completely you will have a zero, or very low, reading in the cylinder. If partially open a comparison between cylinder readings will tell a tale.