Recently bought a 1987 245DL with 289k for my fiance as a project... after reading the sage words from this board (and looking under the hood), I see I have harness rot. The engine runs, however (though very roughly) with the following symptoms:
1) will start then die immediately UNLESS the return line on the injector rail is PLUGGED (of course, does not sound safe) (note: new fuel pumps and regulator were put in right before I bought, and injectors all 'click')
2) sputters under the slightest load, but recovers if throttle is opened quickly
3) after warm, the engine 'cycles' (high rpm<->close to stall) when the throttle is held in one position, except near full open ( where it runs strong, or cycles so fast you can't notice)

I've diagnosed temp going to the ECU, and AMM resistance... so far all seem OKAY (but have not tried 'limp home' with the AMM).

Before I reharness this baby, just wanted to see if anyone else has seen this issue and might offer hope. I want to get the engine running smoothly before I take the time to throw on new wheel bearings, struts, shocks and tailgate harness, and diagnose/fix the O/D. Body is in great shape, and that great dark Volvo blue...

Anyone think this could be anything more than harness issues? Hopefully not ECU...
Cheers,
Lance