v70xc 98 fuel system malfunction

llama_of_doom · Post by **llama_of_doom** » 12 Aug 2009, 22:02

So I just cut my car apart to get my fuel pump out, once out I decided to just test the fuel pump at this point I noticed that the pump already in the car was not stock, its a walbro! which is what I have to replace it, only the walbro I was sent by the site I bought it from is not the same type. So if anyway knows exactly what is supposed to fit into the v70xc from walbro please let me know. I was sent a GSS340 it seems like some past postings for the regular v70 call for the Walbro 5CA3351. There are some differences the one I was sent is shorter and the top line coming out of the fuel pump will need to be modified to fit in place, also the strainer I was sent will in no way fit in the housing. But I digress, I tested the walbo that I had taken out of the car and it worked long story short I had put the original walbro back in the car and I changed my relay. I turned my car on and it ran for about 5mins until the pump started making some odd straining noises, then the car stalled and refused to restart, I could hear that the pump was no longer turning on when I turned the key to the on position. So either I put a bad pump back in the car and it worked momentarily when I brought it out....or I have some odd electrical problem... or I was thinking there is some sort of electronic fuel controller on the car somewhere that may be responsible for regulating voltage to the pump to sort or vary the speed that the pump will work depending on driving conditions. I was thinking that could be the case which might be the reason the pump worked out of the car and only worked for a little bit then started making weird noises when in the car. Perhaps its not getting enough voltage and what I thought was a dying fuel pump was a underpowered fuel pump struggling to stay on. If there is a electronic fuel pump controller where could I find it on the v70xc any pics from the service manual would be a great deal of help. thanks!

Post by **Ozark Lee** » 13 Aug 2009, 02:39

Your problem sounds very much like the fuel pump relay. You can jumper it with a paper clip to verify that but here are some detail on where it is:

https://www.matthewsvolvosite.com/forums ... php?t=9681

To jumper the relay put the wire between the socket positions associated with pins 15 and 87.

...Lee

llama_of_doom · Post by **llama_of_doom** » 13 Aug 2009, 13:46

thanks for the quick response Lee but when I tested everything off he car I forgot to mention I also tested on the car with a jumped relay and it worked. I then proceeded to reassemble everything and then I bought a new relay. Well with the new relay and I had the car working for about 5 mins until it completely died now the fuel pump refuses to prime, or run at all. This is why I was thinking either I was really unlucky by testing the pump off the car and having it work and then it turned out to be bad and now refuses to turn on or there is another component in the fuel system that regulates voltage to the fuel pump and that is the reason my pump will not turn on because its not getting any power. Just to clear things up and eliminate variables I have a brand new relay from Volvo in the car right now and my fuel pump will not switch on.

llama_of_doom · Post by **llama_of_doom** » 14 Aug 2009, 21:40

my lengthy explanation aside for those who do not want to read it, can someone tell me if there a component on the car controls or regulates voltage to the fuel pump? if possible please include the related information from the repair manual.

llama_of_doom · Post by **llama_of_doom** » 15 Aug 2009, 18:53

bump for the the whereabouts of the fuel pump controller

Post by **Ozark Lee** » 16 Aug 2009, 11:37

The only "controller" is the fuel pump relay and it is quite binary - On or Off. You should have battery voltage at the fuel pump when it is on.

...Lee

llama_of_doom · Post by **llama_of_doom** » 16 Aug 2009, 11:45

any advice would be appreciated I don't have the repair manual which I think I'll be changing shortly so if someone could look this information up for me it would be awesome, if not I'm going to go to the dealer tomorrow and see if I can get them to tell me anything.