On my 97 855 GLT, that hose is for providing intake manifold vacuum back to the fuel pressure regulator. In my opinion there is no reason the hose needs to be rated for fuel. I replaced the rubber hose with silicone about 10 years ago and it has been working well with no issues noted.

Here's a photo of the fuel line and two 90 degree fittings I used on my 97 855 in Dec 2022. Still working with no issues noted yet.

It sounds like you are trying to measure the resistance in the wiring harness and verify the harness itself is OK. One way to do that is to measure each wire one at a time in the harness from the pins inside the CPS sensor connector back to the ECU to make sure each wire individually is low ...

I used the 5/8" fuel rated rubber hose too on my 1997 and it has been running great for the past 3 years. No problems or codes noted.

The Volvo 850 1995 troublshooting guide states 200-500 Ohms for the CPS:
"ENGINE SENSORS & SWITCHES
CAUTION: To prevent damage to Electronic Control Unit (ECU), ensure ignition switch is in OFF position before disconnecting or connecting ECU.
Crankshaft Position Sensor
Crankshaft position sensor is ...

When you are testing for spark at the coil and at the plugs, are you using the same grounding metal for the test?
Asking because it could be a poor/high resistance ground on the engine block is preventing the spark at the plugs.

MOR80, you're saying above that the cooling fan is not turning on? If so, have you tried connecting 12V directly from the battery to the fan to verify that the fan motor works when power is applied?

Replaced the ignition coil and camshaft sensor today. Still no start. Cannot replace the distributor rotor due to a damaged bolt head but it is spinning along with the crankshaft.
I have a doubt about my firing order and if it is correct or not. In the specifications document the firing order is 1 ...

If memory serves correctly it is the 'kick down' switch that will sense when the accelerator peddle has been floored.

https://www.craigslist.org/view/d/cedar ... 1eTmRoRZY8

Good looking 2001 V70 turbo