Fuel leak coming behind hard fuel line near firewall

Post by **m491** » 15 Jul 2013, 10:14

I have searched the various 850 fuel leak posts and none of the normal (gas tank hose, injector leaks) match what I have in my son's 94 850 NA 5 speed.

He complained of a slow start up (a couple of turns vs the normal firing on one turn) and I thought it was a bad fuel filter (which is due for replacement) as well as a possible bad fuel pump. Something was causing a lower pressure at start up. In the mean time I was fixing a CEL on my daughters 850 wagon and let this slide for a week. Now there is a strong smell coming off the car and his milage is dropping. he parks in the street and now there is a 10inch dried puddle from a gas leak. I crawl under the car and see the dripping after he just drove the car coming off the fuel lines right under the start of the firewall. The fuel lines inside the engine compartment are metal and none of them have any leaking. I can kind of see dampness at the end of the metal lines. Without having a lift and not wanting to drive the car onto the driveway right now, can someone tell me if the hard lines convert to rubber fuel lines under the car? Are there any couplings or fittings that could go bad and cause a decent dripping of fuel?

The leak seems to be low near the bottom of the firewall on the passenger side. It appears to stop after the pressure is relieved from the system. If anyone has done this before can you let me know if this is a DYI or shop only type repair.

Thanks folks.

Post by **cn90** » 15 Jul 2013, 11:23

Check out Part # 13 in the photo below:

: FuelHose.JPG (99.94 KiB) Viewed 1916 times

Post by **m491** » 15 Jul 2013, 14:19

Thanks CN90. I was looking at the same diagram but was wondering if there was a "smoking gun" know issue like the rear gas tank hose. I take it this is the full length hose(s) coming of the front of the hard tubing back to the fuel filter.

Has anyone taken these lines off and replaced them? I guess if the system is already de-pressurized it should be plug and play, right? I haven't moved the car from the street because each time it pressurized the fuel system and make a mess. I have to get it up on the driveway and let it spill on some cardboard before pushing into the garage.

Post by **m491** » 15 Jul 2013, 18:54

I actually got a better look after work and see it is actually a value of some sort at the beginning of teh fuel line that is very rusty and metal is flaking. I figure the fuel system pressure has found a pin hole and is leaking from the valve (see picture with green arrow).

It looks like it would slide off similar to the fuel filter but I see no part number out there for the valve. I hope this doesn't mean I need the entire line. Has anyone done this repair before? I'm going to try and get up to a local pick-n-pull tomorrow after work and hope a NA car is there. My other kid's turbo doesn't have this valve.

Post by **m491** » 15 Jul 2013, 19:20

I did some more looking up of diagrams and see it is called a "pulsation attenuation." This looks like part of the actual fuel line and not a stand alone part. Which really is disappointing because I could change this like a fuel filter up front with only the hood up. If anyone knows if it is safe to replace this and not the entire fuel line please let me know.

I found some good info on the following thread about the pulsation attenuation.

https://www.matthewsvolvosite.com/forums ... 3&p=257300

Post by **cn90** » 15 Jul 2013, 20:55

I don't think the pulse regulator is that crucial.
Maybe you can remove it and replace with standard fuel hose + metal barb fittings + standard clamps?

Another option is to bite the bullet and replace using Volvo fuel hose ($86). If you plan to keep the car another 5 years, then $86 is not that bad.

Post by **m491** » 16 Jul 2013, 05:25

I'm looking for a replacement at a pick n pull later today. If not I guess I will be spending the $86 and learning how to pull off all the shields and hoses back to the fuel filter.

I'll follow up in case I can get any part number in can find on the pulse attenutor at the junk yard.

Post by **cn90** » 16 Jul 2013, 05:56

Most pulse regulators are probably rusted out at the junkyard anyway, so personally I'd not waste time looking for a used regulator.

Some Volvo models don't even have this thingy. If you get a long metal pipe (maybe 3-4" long), then just remove the regulator and bypass it using a metal pipe. Chances are the car will run just fine w/o the regulator.

Post by **m491** » 16 Jul 2013, 06:51

My 96 Turbo and 97 GLT don't have this on that section of the fuel line. But don't some models have the pulse attenuator up near the fuel rail? I think I saw some mention of that when looking for information on this issue.

I wonder why Volvo used these to begin with. I may go the metal fitting instead of the full line replacement. I still might go to the junk yard and cut a section of the line so I can get the correct fitting size.

Post by **cn90** » 16 Jul 2013, 07:48

Personally, I think this is a gimmick.
Just get a ruler and measure the regulator outlet diameter. This will be your metal tube O.D.
Most European cars have fuel hose with I.D. of 8 cm or so.