1991 940 se all original. Has been running fine drove home from work, went out later and it won't start. I have it narrowed down to a fuel issue. Spray ether in it, it will start. Tank has fuel, I can hear the fuel pump running and the relay clicking. without ether it will fire for just a second like it wants to start but won't. Where should I look, weak pump maybe? Any help would be appreciated..

 

thats actually a 960 turbo.... it has the 4 cyl turbo engine of a 740/940 but the body and interior and a lot of the wiring are more in common with the 960.

um, first thing I'd check is to see if the fuel injectors are getting power.... if you unplug one of the injectors, switch the car on, one of hte pins on the harness plug should have 12V on it relative to engine ground. this power comes from a 'radio suppression relay' under the hood, I believe on the left fender on that version.

91 is a early LH 2.4 turbo, some of those had defective ECUs, there's a list of the ECU versions here...
https://www.volvoclub.org.uk/faq/Eng...ReferenceChart
(but hmmm, it suggests you probably have a -560, and it was the pink label -561 non-turbos that were prone to problems).
this ECU is mounted on the right side of the passenger footwell, just forward of the lower hinge to the front right door.

more ECU diagnostic tips here,
https://www.volvoclub.org.uk/faq/EngineFIComputer.html

and some more diagnostic tips here,
https://www.volvoclub.org.uk/faq/Eng...injection.html

 

thank you for the quick responce. after work i will start testing and what i can find, i will post results.

 

​​​​​Did a little testing, here is what I have so far. All fuses involved are good. RSR had dirty contacts and the connector is coming apart. I cleaned the contacts and seated them back into the connector.RSR is getting power and signal from the fuel pump relay behind the ashtray. Injectors are getting power.moved to the fuel pump relay seems to have been replaced at some point, it clicks when key is turned on. Then I checked the pumps, turn key on hose in tank and can hear the in tank pump working but main pump not working. Key on and while cranking main pump didn't work. Check voltage at the pump with key on and no voltage. Pulled the fuel pump relay and jumped 30, 87\1, and 87\2. In tank pump came on but not main pump and still no voltage. Pump has been replaced at some point also, still kinda shiny and it looks like they spliced new wire with connectors to the original wires and the connection is taped up. I ran outta daylight but need to check their splice and see if I get power before their handy work. Does it sound like I'm on the right track? Maybe the tank pump is pushing a little fuel to the rail when I try to start it, it wants to start it barks and fires off just won't start all the way up.