Intermittent No Start
 

Just picked up my 1991 240 Wagon yesterday. We were having trouble getting it start. The seller told me he would have intermittent issues with it. At first the fuel pumps were not coming on. We bypassed the relay and they both worked. Plugged the relay back on and they both functioned. Still no start. We pulled the plug wire closest to the front to test spark. Spark was good. Plugged the wire back in. The car started right up and has every time since. The only code I'm getting from socket 6 is 144- Load from ecu missing. The cap and rotor are new and so is the coil.
Any ideas for what would cause this, and why pulling that spark plug wire would make a difference? Thanks for any help, this 240 is a whole new beast!

What condition is your crank position sensor? If the insulation on the wire that runs from the sensor is cracked and flaking off then it may be the culprit.

In your post it wasn't clear whether it only would run when bypassing the fuel pump relay or not. Before replacing other components make sure that the fuel pumps are running properly without bypassing the relay. If starting is intermittent then the CPS is the next thing I'd check.

Oh sorry that wasn't clear. It will now start and run without bypassing the relay. I have started and driven it multiple times now with no issue. I will look into that sensor.

if its running, the crank sensor is good.

wild guess says, that spark plug wire wasn't snapped down before, and now it is.

yeah, maybe. It did start the day a went to look at it first, which was a few days before I had the issue. I am a little doubtful of that because it had so many parts replaced, but I have no better explanation at this point haha.