Ok fellas, here is my previous thread where I was trying to figure out why my car would only very occasionally have what seemed like a fuel starvation issue:
https://volvoforums.com/forum/volvo-...k-issue-62981/
It now seems I have figured out what is going on, since the same issue occurred in my driveway just a few minutes ago. After about two minutes of idling, I shut the car off but then decided I wanted to re-position it despite the fact I had just shut it off (because I was being picky I guess). I go to start it, and what do you know! Sputtering and dying from what seemed like fuel starvation. I tried starting my car multiple times, but the first time it ran just a bit but very roughly (off residual rail pressure I imagine) and the other times it just refused to start at all. So, after all of that I put the key in the ON position and very quickly went to listen under the car to listen for my fuel pump, but I did not hear it running at all. Suspecting that it was not the pump itself failing but rather the fuel pump relay being randomly stubborn again, I went to the key again and rapidly switched it ON and OFF about ten times to convince the seemingly stubborn relay to start the pump again. After the key cycling but before attempting to start the 850, I listened to the pump again and heard it humming away happily before it stopped like it should, which told me I should go try to start the car again. I turned the key to the start position and the car started right up and remained running! So, all of this makes me thing the relay is acting up, but only acting up rarely and whenever it feels like it, as opposed to being temperature related. Opinions?
So, now comes the questions bit:

1. What is the relay I need, and where is the cheapest place to buy it?
2. Where is it and how do I replace it?
3. Do I need to do anything to the relay before I install it or is it just a simple "unplug-old-part-and-install-new-one" scenario?

Thanks in advance!

1995Volvo850

 

FYI the pump only runs for a couple seconds to charge the rail when you put the key in Position II, unless the car starts and then it kicks on until the engine is stopped.

So if you put the key in II, then get out and listen, it will be off already regardless of whether the relay is operating properly.

edit: Pull out the carpet in your trunk floor and leave the trunk open. Try it again and you should be able to hear it from the driver's seat.

 

Well, I knew that already, and I am sorry if I did not make that clear. Indeed it does shut off a few seconds later, but I still heard it for a short bit before it quit. Before I couldn't hear it at all. I can also barely hear it from the driver's seat, but quickly jumping out and listening at the tank is good for clarification.

 

FCP has a KAE relay for 39.95 (Volvo Fuel Pump Relay (850 C70 S70 V70) KAE 9434225 | FCP Euro) or a genuine Volvo for 45.15.
(Volvo Fuel Pump Relay (850 C70 S70 V70) KAE 9434225 | FCP Euro).

It is located in the fuse/relay box. You have to remove the top cover to access it.

http://www.matthewsvolvosite.com/for...3c6166062053d7

 

Thanks!

 

Ok, I fixed it!!!!

As it turns out, my issue was the relay!

Thanks to all who have helped me in my various threads to help me fix this previously very aggravating, inconvenient, and baffling problem. I also hope that my descriptions throughout this issue have and will help others with similar issues.

Case Closed

lol