Hello All. I have a 1995 Volvo 940 non-turbo wagon. It has problems cold starting and when it starts the idle is very rough. I've replaced the crank angle sensor, Mass Air Flow sensor, throttle position sensor, idle air control valve and still not starting. I've located the radio suppression sensor but don't know where the fuel pump relay is. Can someone show me where it is? Looking at the diagram they have for relays which is in front of the shifter, the slot where it appears in the diagram has no relays in my car. Many thanks in advance.

 

(I moved this to its own thread)

95 non-turbos rewired the ECU/fuelpump relays. instead of the classic dual relay all the other LH 240/740/940 used, they ran the ECU power on the 'radio suppression relay' under the hood, and put the fuel pump on a simple relay plugged into relay "M", row closest to the fuses, 2nd from the right.

 

sounds like maybe your coolant temp sensor is fubar (or the wiring to it).

best way to test it is to get the car hot, unplug the ECU, and use a multimeter to measure the resistance at the ECU connector... there's a table floating around, but it should be like 300 ohms or something when the car is hot (80c), 3000 ohms (3kohms) at 'room temperature' (20c), 5-6K ohms at freezing (0c)..... The CTS is one of the sensors screwed into the block under the intake manifold... it has 2 pins, the 1-pin sensor goes to the temp gauge in the dash, and the other flat thing is the anti-knock sensor.

 

"very rough idle" sounds like a severe engine missfire to me... Relays don't cause that.
Take a compression test to eliminate serious issues like burnt valves and headgasket, then examine the ignition tune-up items like plugs, wires, cap, etc.