Fuel pump relay wiring

kuesfam_mnl · Post by **kuesfam_mnl** » 29 May 2012, 18:45

I have a 1995 volvo 850. It has been off and on running and not for 3 months. I know its a fuel issue. I have constant power to fuel pump relay from fuse box. I also have a brand new relay (old one is still good cause I had both checked) I still have no power to the fuel pump. (every once in a while it will work for a few days then die) I know that the pink wire is the power to the pump, so my thought is maybe bad connection to relay? Or worse case scenario a short in that wire somewhere in between the relay and pump? I will be taking the fuse box apart to check the connection in the next three days, however there are other sets of wires from the fuel pump that I don't recognize. There are a grouping of four wires which seem to be for the sending unit, but there are two wires (one brown the other white or black) don't know where they go or what they do, but while looking at parts for my car (i work at Napa) I found in the fuel pump related parts an emergency fuel shut-off switch!? Is this what those wires are for? Is my car even fitted with this, and where can I find it, if so? Also need to know how wire is ran from relay to pump. Under the car? Under floor carpeting? Passenger side/drivers side? If anyone has any other ideas it would be greatly appreciated.
Thanks,
Marcus (new to the volvo's)

I do have spark, all ignition system is working fine. When i put starting fluid into the manifold it fires then dies, that is my belief why it is fuel issue. Also checking shrader valve asap but reason to believe low pressure due to not firing. Also tried "tricking" fuel pump to stay on for a few seconds by cranking then leaving key on and still no power to fuel pump, but constant power to relay. This is why I think it has to be wiring issue from relay to pump.

valvster · Post by **valvster** » 30 May 2012, 08:12

Sounds like your fuel pump is dying or dead.
Thump the bottom right of fuel tank with a rubber mallet or kick it with your boot, that may revive it for awhile.
https://www.matthewsvolvosite.com/forums ... =1&t=45936

Valvster

Post by **jblackburn** » 30 May 2012, 08:38

I still have no power to the fuel pump. (every once in a while it will work for a few days then die)

No power at the wires TO the fuel pump, or the pump just isn't running?

Post by **jimmy57** » 30 May 2012, 09:18

There is no fuel pump impact switch to reset on Volvos.

kuesfam_mnl · Post by **kuesfam_mnl** » 30 May 2012, 14:58

There is no power to the fuel pump. The pump is brand new! and has been tested after initial installation! The loss of power is in between the relay and the pump. I just looked at the wiring diagrams on this site (which are awesome) and I think I need to trace the pink power wire connection to the relay first, then the connection to the harness under the glove box next to the passenger door. I still haven't got a chance to work on it but trying to tomorrow, and I will respond back with findings. Due to the problem being "off and on" I still think my best chance is the ground wire connection must be loose or not a good connection, but worst case scenario, a short in the pink power wire for the fuel pump somewhere, which means running a new wire from relasy to harness under dash then new wire from harness to fuel pump.

kuesfam_mnl · Post by **kuesfam_mnl** » 31 May 2012, 15:24

So I checked the ground wire and it was still good, clean and tight. So now I'm almost certain it is the power wire from relay to pump. To test this, friday evening I am running a totally new wire from relay straight to the pump by-passing the harness under the dash. If I get power and its running I know one of the connections either to the relay, or the harness on either side was loose or bad. I'm not certain, because I am new to volvo's but If the new wire works I will continue to by-pass the harness and just neatly run the new wire next to grouping (of other wires) to the pump. I hope that everything runs perfect after this, after all the research I have done this seems to be the only option. Wish me luck! And thanks for the comments and help.

Thanks, Marcus

kuesfam_mnl · Post by **kuesfam_mnl** » 11 Jun 2012, 18:27

So, I finally was able to re-connect the wires to the fuel pump relay and am now getting constant power. I then realized that my fuel was running straight through my fuel rail and back through the return line. After pulling the vacuum line from the fuel pressure regulator, and seeing fuel drain out, I replaced the regulator. Now I have good fuel pressure, but now I am not getting a pulse to my injectors. I then tested this with a noid lite test kit, and low and behold no pulse. After reading some posts on this site, I then tested my camshaft position sensor and found it to be faulty. I replaced the sensor and the car fired up and has run perfectly about 50 miles and counting with no check engine light or any other problems. So in the end it was a combination of bad wiring to the fuel pump relay, bad fuel pressure regulator, and a faulty camshaft position sensor. I bought the 95 volvo 850 5-speed for $600 and with registration, oil change, tune-up, and other parts, I am into this car about $1250. Not too bad! 147,xxx miles and plenty to go! Thanks for everything Matthews Volvo Site! The info from past posts to the wiring diagrams made life a lot easier with diagnosis as well as ideas from other users from past experience! Thanks to all!

Marcus Kuespert White 1995 Volvo 850 N/A 5-Speed w/ 147,XXX (New 2 Volvos)

Post by **jblackburn** » 11 Jun 2012, 22:21

Wow, talk about EVERYTHING possible with the fuel system going wrong. Glad you got it all sorted out and running again!

reggie1364 · Post by **reggie1364** » 27 Sep 2014, 19:16

kuesfam_mnl wrote:There is no power to the fuel pump. The pump is brand new! and has been tested after initial installation! The loss of power is in between the relay and the pump. I just looked at the wiring diagrams on this site (which are awesome) and I think I need to trace the pink power wire connection to the relay first, then the connection to the harness under the glove box next to the passenger door. I still haven't got a chance to work on it but trying to tomorrow, and I will respond back with findings. Due to the problem being "off and on" I still think my best chance is the ground wire connection must be loose or not a good connection, but worst case scenario, a short in the pink power wire for the fuel pump somewhere, which means running a new wire from relasy to harness under dash then new wire from harness to fuel pump.

I used another forum to change my fuel pump, but appear to be having the same "pink" wire issue with my car. Does anyone have a link to the wiring diagrams mentioned? I'll need them as I trace and run new wire myself.

Thanks!

Post by **Ozark Lee** » 27 Sep 2014, 23:55

We can no longer host the schematics due to objections from Volvo's legal department. They can, however, be downloaded from this site:

http://www.volvowiringdiagrams.com/

...Lee