How to install a fuel inline check valve, 00 V70

falconbrother · Post by **falconbrother** » 28 Apr 2011, 14:56

If you have a hard start issue it very well may be a bad check valve in the fuel pump. If you think that this is you go on-line and order a 5/16 in-line fuel check valve.

The fuel line runs out of the in-tank pump, down the right rear wheel well to the fuel filter, then under a plastic cover to the firewall. I placed my check valve under the car in a recess under the front passenger floor board where it's not likely to hit something in the roadway. You can place yours where you wish.

When you cut the fuel line you will notice that it has a rubber outer and a nylon inner hose. Cut out about an inch or slightly more of line. Carefully trim the rubber outer off of the fuel line leaving exposed about a half inch of the nylon line. Do this on both sides. Be careful. A sharp razor will slice right through the nylon like butter so be careful.

In the check valve kit there is a check valve with two brass ends. Leave the ends off for now and make sure that the body of the valve is tight and secure. Slide each on the exposed nylon line and then insert the white nylon compression seal over the nylon hose. Place the check valve body in the cut out section and finger tighten each side. Make sure that the compression seal has been inserted so that the cone end is facing out towards the cap on each end and ensure that the one way check valve body arrow is facing the front of the car. Now get a 5/8 and a 3/4 open end wrench and tighten each end being careful not to over tighten. Get it good and snug but don't strip out the brass threads. Now, take the mounting clip and place it around the body of the check valve. Pick a drill bit that's the size of the self tapping screw just under the threads (so they have metal to bite). Drill a hole so that the clip will hold the check valve securely. Insert and tighten the screw.

Check for leaks. You're done.

falconbrother · Post by **falconbrother** » 30 Apr 2011, 20:13

Here's a picture.

falconbrother · Post by **falconbrother** » 25 May 2011, 21:14

Update: Use caution with this repair, especially if your car uses Volvo part number: 1275658 for the fuel pressure regulator/damper/absorber (it's known by all three names).

In hot weather the check valve may cause excessive temperature related pressure to build up in the fuel line at the fuel rail and damage the fuel pressure damper. According to Volvo service a hard start condition, related to decreased fuel pressure on the rail, is more likely related to leakage inside of the fuel pressure damper than to a faulty fuel rail. According to Volvo service, failure of either part is rare but, the damper fails more often than the fuel pump check valve. If there is a problem with any part of the fuel system fix that rather than adding parts to the original design, per Volvo.

Post by **shiloh51933** » 24 Nov 2011, 12:37

falconbrother wrote:Here's a picture.

Since you've introduced this after market check valve into your fuel system have you had any issues as mentioned in the later post? I'm having hard starting issue due to fuel pressure loss after turning engine off. I checked the pressure with a fuel pressure gauge and she drops to 0 immediatly after turn off engine. You mentioned the damper being possible issue, have you looked into that possibility?

mrjacobrussell · Post by **mrjacobrussell** » 01 Jun 2012, 00:39

I was considering doing this modification as a work around until I can schedule time to take off the tank and swap the pump.

I used a pressure tester to watch the pressure at the rail , it was perfect during engine running, but dropped to zero when I turned off the car .

Have you had any problems with this modification ??

Post by **JRL** » 01 Jun 2012, 08:29

Listen, since I was the person who found this fix and posted it a few years ago, we have fine tuned our installation
You mount it directly behind the fuel filter (which you should buy a new one BTW). Butt it right to the back of the filter

mrjacobrussell · Post by **mrjacobrussell** » 01 Jun 2012, 10:36

JRL wrote:Listen, since I was the person who found this fix and posted it a few years ago, we have fine tuned our installation
You mount it directly behind the fuel filter (which you should buy a new one BTW). Butt it right to the back of the filter

Do you have any pictures ?

Your saying mount between the filter and the tank correct ?

jonl · Post by **jonl** » 21 Jun 2012, 09:55

JRL,
What's accomplished when you install the CV behind the fuel filter?

daviddstubbs · Post by **daviddstubbs** » 16 Aug 2012, 00:52

Where the heck does one find a fuel-rated check valve like this? Lots of air valves, but this bit seems rare, at least to Google.

Is there an opening pressure, e.g., 5 PSI, to look for?

What barrel (inside) diameter , e.g., 5/16, or is that some other dimension?

Thanks very much for the clues about installation!

David Stubbs
Portland, Oregon, US

Post by **rspi** » 16 Aug 2012, 08:56

I always thought the fuel pressure regulator kept pressure on the system. I also thought the fuel filter had it's own check value.