Apologies for the late reply, everyone. I was busy finishing up my junior year of college, but my attention has turned back to the 780 as a summer project. So, here’s an update (Spoiler alert: no start as of yet).
First I changed all 4 spark plugs, and replaced the fuel pump relay, as well as the radio suppression relay. However, these made no change, and testing revealed they were actually functioning anyway. I performed a compression test on all the cylinders in the B230FT, but they returned negligible readings on all cylinders (like 20psi!). From this, I gather that there’s either been a catastrophic head gasket failure, or the block cracked over the winter because the cooling system was filled mostly with water, not antifreeze, which expanded and cracked the block. I don’t think it’s timing belt/valve related because the cam does move when the car cranks. However, I’ve never seen a car lose compression in every cylinder, and it’s definitely left me scratching my head. The fuel pumps, relays, and sensors all check out. It’s been narrowed down to this.
An engine rebuild is beyond my means because I’m just a student, but I was able to source a B230 engine nearby from a wrecked 240. Would I be able to have my mechanic directly swap this into the 780, fitting correctly to the trans? Just to be clear, I would be swapping the non-turbo engine into the turbo car. The engine comes with the 240 ECU and everything except injectors, but I imagine that the 780 injectors would fit right on.
If anyone has any ideas, please let me know. I really want to get this thing back on the road- it looks so sad just sitting there. I’ll go sit inside it sometimes just because the interior is such a nice place to be. If anyone has any alternative theories (if I’ve mis-diagnosed the issue) definitely suggest them. If anyone’s interested in buying the car as a parts car or a project, let me know. It’s not the world’s prettiest 780, but there’s hardly any left. My friends/parents want me to junk it and I can’t bring myself to do that, but if I can and put the money toward another project, then I may just have to. Getting it back on the road, however, is my main goal.