If there is no pressure in fuel rail after the fuel pump is primed...then fuel pressure regulator is at fault returning all the fuel back into the tank....or leaking into it's vacuum line.

Is your FPR at fuel rail or somewhere else?

According to the picture you provided via link...it's on fuel rail.
Two pipes going by the timing belt cover...one for fuel feed...one for return from fpr.

I’ll guess you have a lot of marginal parts in the car , ok in sunny California but places with real climates need good parts Spark plugs, wires , cap rotor will cost about $200 and need doing. Measure the fuel pressure at rail, get a number , not a spritz measurement. Autozone will loan you the. Ga...

If you don’t have codes then the gas tank is sealed up, So water in the gas is ruled out. A pressure measurement on the rail will tell you if the relay or pump is failing, that’s a typical cold weather crank, no-start diagnosis. You can also confirm with a shot if ether, or starting fluid into the s...

That battery voltage is falling too low to keep the CDM logic circuitry happy. Watch the cranking voltage to see how low it drops..wiring or battery test under load needed.

Check B+ connections at fuse box, starter, and alternator, check for resistance in B+ connections, then check grounds. Try bridging starter relay with two screwdrivers or a wire. If no crank you either have bad battery or bad starter. Can check battery by watching volts while cranking. Should drop b...

It doesn’t sound like a Sensor but Diagnosing by symptom is unreliable.

Can you describe what “ low compression starting ‘ sounds like? Does the cranking change or is it just not firing?

Fuel pump relays on high mileage cars get iffy and temperamental; that’s an easy swap with a junkyard one

That sounds a bit like lawn mower syndrome. Excess gas washes down the oil in the cylinders and causes low compression. It’s usually caused by a marginal Engine coolant temperature sensor Which then commands too much gas injected ona warm start. Diagnosis. Get out the ohmmeter and compare the ECT re...

It was about 18 degrees F that day, fwiw. He has looked at it and tells me there is plenty of fuel pressure, so I asked what could be the problem. My 1998 C70 won't start when it is that cold. The barometric pressure sensor craps out at them temperatures ( AKA Altitude Sensor (MAP Sensor ). A shot ...

That green stuff is brass contact corrosion. Use an old tooth brush or brass brush with contact cleaner and clean all that stuff off. It acts as a barrier to electrical parts getting current. Check the one on the MAF as well. It is likely the same.

Sorry not sure where that pipe goes on a 98.

Neil.