My volvo has been having an intermittent no start problem. At one point it didnt start for two days, then fired up and worked fine. Now it wont start again.

It has spark, so it probably fuel related. Where do i start?

Edit: It has new spark plugs& wires. cap & rotor.

 

classic fuel pump relay symptoms. but of course, it could be something else, too.

 

I changed the relay when my car wouldnt start and it started right up.

What is the difference between the fuel injection relay or fuel pump relay second row on left, on some diagrams, and the other one that is fuel pump relay in the furthest back row?

 

on all the LH 240/740/940's up until the 1994 940 non-turbo, the fuel pump relay was a double relay that has two parts, one part controls the power to the ECU, while the other part controls the power to the fuel pumps (and o2 sensors). On the 740/940's they put an additional relay under the hood to switch the power to the injectors and ignition coil as the relay panel on the 7/9's is too close to the stereo so switching that power via the fuel pump relay was causing radio interference, hence this extra relay is called a 'radio suppression relay'.

on the 1994 940, they figured out they could use that radio suppression relay to power the ECU too, so they didn't need an expensive special dual relay for it, so they moved the fuel pump relay to the rear-most row, 2nd from the right if I recall, where they put a standard sized plain single relay just for the fuel pumps. On the 94/95 turbos they did NOT do this, not sure why.

 

Thank you for the explanation pierce

A little update. I changed the fuel pump relay in the front, and i have had zero starting issues since. I opened it up and saw that each time i turned the key the relay didnt always engage both lever things. When it did, the car started. When one or both didnt, the car didnt.