My 1992 240 has a crank no start problem. There is a Schrader valve on the fuel line just before it enters the fuel pump underneath the car. Hooking a fuel pressure gauge to it shows no pressure under any conditions. Would this indicate a problem with both pumps...or just the in tank pump?

I can hear and feel both pumps getting power.

 

Hmm, how do you "feel and hear" pumps getting power?
Normally a bad in tank pump won't prevent start, but I follow your logic.
Relay good?
I'd squirt some starting fluid in the intake just to make sure it's gas issue... for starters.

 

When the key is moved to the kpll position...in a quiet environment... the main fuel pump can be heard from the drivers seat doing "something". I've always thought it was getting power and priming up.

My grandson cranked the key while I laid underneath and I could feel the pump do "something"

My grandson also cranked the key while I listened for the in tank pump with the access cover removed and I could hear it do "something"

I can't say that either pump is getting a full 12 volts.

The problem started as intermittent stalling... Sluggish at times... Seemed to happen at less than half a tank gas. It has now evolved into a crank no start

Replaced CPS after testing on a running 740 showed the CPS on the 240 was bad ( the nub on the sensor was also visibly worn also)..thought that was the cure but no.

Swapped fuel pump relay with 740... both good

Swapped radio suppression relay with 740... both good

Swapped and greased powerstage with 740... both good

Swapped maf sensor with 740... both good

I've done nothing to the car except change fluid's since I bought it with no service records. So I changed plugs cap and rotor with made in mexico Volvo branded $4 each plug's (denso plugs came out of it) and Bosch cap rotor

No engine codes...timing belt intact.

 

Swapped out both fuel pumps....car runs now.