2000 V70-XC Fuel pressure is at 20 and drops to 0 when off

alex7 · Post by **alex7** » 10 Sep 2014, 18:18

My Volvo keeps pulsating and dies while driving at stop. I changed the MAS, and got more power but, it is still hard to crank at first. It takes about 4 tries until it cranks. Any suggestions of what the problem may be?

DrJammer · Post by **DrJammer** » 10 Sep 2014, 19:07

Hi there, I am going through similar issues. Losing fuel pressure rapidly after car is off is a sign of a faulty check valve. The check valve is incorporated into the fuel pump assembly which apparently is a bear on the XC models.

Search for check valve, in line check valve, fuel pump, and fuel pump relay in the forums.

Jumping the fuel pump relay could be a quick and easy fix.

Post by **Ozark Lee** » 10 Sep 2014, 19:12

20 PSI is way low and it should hold pressure. What are you using for a pressure gauge?

If the numbers you posted in the title are accurate then you need to replace the fuel pump, the entire assembly and not just a cartridge. I say that about the cartridge but I actually tried to find one and couldn't for an XC.

Now for the bad news. Replacing a fuel pump on an XC means either dropping out the entire rear suspension and drivetrain or cutting a hole in the floor under the rear seat. The latter method is much, much easier and it patches up OK. We have some details on the "cutting a hole" method in the repair database.

...Lee

alex7 · Post by **alex7** » 11 Sep 2014, 05:06

If I do jump the fuel pump will that build up the pressure? I now need to replace the starter all this cranking has made it come apart. I think I will cut the floor out if I have to. That seems easy than the other. Do you think that will fix the pulse when I start off. This has been a great car I only have 176000 miles on it. I can see how they saved money on this car. They made the wires with the smallest gage wire they could find. The fuel pump is $300. and starter holy crap must have gold in it..

alex7 · Post by **alex7** » 11 Sep 2014, 05:09

I was using a snap on fuel gage test kit. I have a friend that works on big trucks.

Post by **Ozark Lee** » 11 Sep 2014, 07:49

The Snap On should be accurate. One of the quick and dirty methods is to use a tire gauge which isn't very accurate. If the pressure was OK but it didn't hold then the check valve is the way to go but since your pressure is that low you need to change the whole thing.

If you shop around you can get an aftermarket fuel pump assembly for a fuzz over $100.00. I don't know that it will last as long as the OEM but after you cut the hole the first time they are a snap to change - about an hour out and back in.

When I have changed them I use what they call a nail plate from the lumber department at Lowes to join the cuts back together.

http://www.lowes.com/pd_14340-166-NP15_ ... 0Than%20$1

I use pop rivets to rivet those plates behind the vertical cuts and then fold the floorboard back down and rivet it to the plates. I make the horizontal cut at the bottom rather than the top and then fold the floorboard up rather than down just because I figure the force from the seat is downward and it seems to retain a bit more structural integrity. I also use some butyl rubber tape to seal the things back up.

That stuff all makes sense when you read this nugget from the repair database:

Fuel pump replacement diy v70xc

...Lee

alex7 · Post by **alex7** » 12 Sep 2014, 04:54

That's for the info. I'm going to try it what have I got to loose. I'm not sure about the tools that he was using but I will take the pic to with me to try to find it. I've got the tools just not clear about when I'm taking it out about the fuel lines? Do you know if the lines are quick connects like the fuel filter our something else? I did get lucky on the starter I bought a new on in 07 found the ticket so I don't have to buy that. Thanks so much for the link that you sent me.

Post by **Ozark Lee** » 12 Sep 2014, 08:02

The lines are a quick (or not so quick) connect. I bought the same tool but I wound up making it a bit differently. Here are some pictures of my version.

What you do is maneuver the tool below the clips on the fuel line connectors and then just pull straight up.

As far as cutting the floorboard goes just use a Dremel tool with a cutoff wheel and just barely go through the sheet metal. The larger the wheel is the easier it goes so have several cutoff wheels available. If they start to wear down in diameter change them out.

...Lee

alex7 · Post by **alex7** » 12 Sep 2014, 10:06

I have a die grinder. I bought some cutting wheels. Do you think it could be cut with out dropping the tank and do you know what side to cut. Is it the driver side rear. Not sure about the pic. Where did you find that tool. I have a snap ring tool not sure what that tool is called you are using. I will be busy Saturday first the starter then the fuel pump. I hate my car..

Post by **Ozark Lee** » 12 Sep 2014, 12:27

The tool began life as a Harbor Freight interior panel removal tool, I think they call them panel clip pliers. The fuel pump you want to change is the one on the left, passenger's side.

My tool was a variation of the same idea that was in this post;

Fuel pump replacement diy v70xc

That repair database contribution is an excellent tutorial. The tank strap on the left side needs to be removed (Use a bunch of PB Blaster on the bolt or you risk snapping it in half). In my case I didn't go to the extra effort of dropping the suspension mount nor did I use a metal plate like the license plate that Brian used in his tutorial. Both are excellent ideas and can prevent accidentally nicking one of the fuel lines in the process but after I looked at the clearances after removing the tank strap I was pretty confident that I could make the cuts without damaging anything else.

Read that post carefully and it will all make sense.

The die grinder should work but the cut will be quite a bit wider than the Dremel tool if your cutoff wheels are like the ones I've seen. The width of the cut really doesn't much matter though unless you wanted to weld the cut back. Given the proximity of the fuel lines to the floorboard, welding the cut probably falls into the "bad idea" category anyway.

...Lee