Hard starting/leaking fuel pressure-related? '97 850 wagon

Pegs850 · Post by **Pegs850** » 25 May 2007, 16:17

I figured out what my problem was. I think it would help you guys:

The '97 850 wagon had trouble starting occasionally. During the trouble shooting process, I found that the fuel pressure regulator always lost all pressure a few seconds after the pump was shut off (the pump was hot wired on, the engine was not running). The fuel wasn't leaking through the injectors into the cylinders because it did not have the tell tale puff of black smoke at startup and did not start as if flooded after having just been shut off and then restarted. However, while this all pointed at the FPR in my case, it does not mean all FPR problems will behave this way.

Part way through '97, the fuel pressure regulator was moved from the rail to about 6 inches forward of the fuel filter just ahead of the right rear axle (the rail has an added "fuel pulsation damper" that resembles a FPR, but isn't). The FPR also costs over $200 and was only available from Volvo. I'll let Europarts and FCP Groton know the part number if they are interested. Be aware that the dealer had trouble finding the correct Volvo part number: 9445592-0.

The FPR on the rail is a fairly easy fix, I'm told. But the one back by the axle is a little more difficult. The axle mounted FPR has 3 plastic fuel lines extending from it. One is about 6" long and attaches to the fuel pump. The other one is a couple feet long and is the return fuel line to the tank. The last line is about 5 feet long and extends up to the rigid line that starts at the rail and extends down between the engine and firewall. The first 2 have these nice quick connect/disconnect couplings that worked surprisingly well. The other has a more typical flaired tube connection.

CAUTIONS:
1) Be careful to not break the rigid fuel line from the rigid tube's nut corroding to the rigid tube.
2) BE SURE TO DISCONNECT THE BATTERY.
3) BE CAREFUL NOT TO HAVE FUEL SPILLAGE.
4) BE CAREFUL TO NOT MAKE SPARKS INCLUDING RUNNING ELECTRIC TOOLS OR TURNING ON/OFF TROUBLE LIGHTS OR FLASH LIGHTS.

Replacing the regulator with the tubes and all can be quite the task. I'd suggest 2 options that would be much quicker:
1) Buy the correct part with all the foolish hoses. Remove the new and old regulators and put the new one the old set of lines.
2) I'm not sure it will work, but I'm pretty sure the regulator that gets mounted on the fuel rail is identical to the one with all the hoses (although a different part number).

For those brave souls:
The removal and installation is relatively self evident for all except the return line. The trick is to take the 2 plates off above the right forward corner of the fuel tank behind the rear seat (the carpeted plywood will have to be removed). One covers the fuel sender, and the other the fuel lines to the tank (the fuel line to the car's middle runs to the filter, the other to the return line). You will see the fuel lines going forward and then down in front of the tank. What you can just barely see is the plastic clip that holds the fuel lines in place. The end of the clip towards the middle of the car can be released but MUST then be pushed totally to the outside of the car so as to not intefere with removing the old line or installing the new one. I discovered this too late and ended up ripping the top part of the clip out entirely after wasting hours fighting with it.

Remove the coupling on the old return line from the fuel tank connections. You can now pull the old line out from under the car. You can cut the old coupling off to make things go quicker.

If your rigid line's nut was not corroded to the tube, then install the new return line before the other lines. Wrap the new return line's coupling in black tape to protect it because it is about to take a bunch of abuse and also to keep dirt out. Have one person at the bottom push the new line up from below being careful to get it in the correct spot relative to the other lines. If the lines are twisted together or not in the right positions, things will not go together. While they are pushing and twisting from below as you need, be prepared to snag the coupling with a HEAVY wire bent into a hook shape. The outside sleeve popped off my coupling, but once I put it back on, the coupling worked fine, so don't panic if yours does too.

When you connect the remaing lines, be careful to make sure the lines are not twisted together and are "relaxed" (that is, that each lines is not twisted about its own axis). Make all of the other connections before replacing the plastic bash plate that protects the fuel line that goes up to the engine so that the bash plate gets put on at the correct spot along the fuel line. Make sure that the lines near the FPR are not going to chaff.

I didn't feel like bleeding the air before starting (snowing and 2AM), but it only made the engine stumble slightly initially and then ran fine for over 4000 miles now.

I hope this helps somebody. Feel free to contact me if anyone has questions.
Dave

polygaryd · Post by **polygaryd** » 30 May 2007, 21:40

is like volvo serious you have to take down the damn rear driveshaft which looks to be a pita as well as the exhaust which i dont even know how you would do without taking the rear diff out to get the gas tank out.. this is ridiculous also my tank looks like it has two pumps. the tank spans the entire back seat and looks to be symmetrical with two pumps one at each end.. the two covers everyone speaks of also doesnt revel the sending unit at all in this car so this looks to be a horrible job and i really dont even want to get into it but i will to figure this out. i am stubborn like that lol... so why is this v70xc so different from pegs850's 97 850 wagon... i am starting to hate volvo seriously. hopefully pegs850 send me some pics of the fuel pressure regulator so i can see what i am supposed to be looking for. anyway anyone ever done this on a v70 xc chime in at anytime to tell me how to get the exhaust out of the way and if there is an easier way..

Pegs850 · Post by **Pegs850** » 01 Jun 2007, 20:04

polygaryd-
Hopefully there is an image below (if not and let me know your regular email address and I'll email all of them to you). It is the fuel pressure regulator plus the mess of hoses. In the background is the traditional massive Volvo fuel pump. The shortest of the hoses goes straight from the FPR to the filter. To see this on my wife's 850, you get just about on your belly ahead of the car's right rear wheel. Peer up at the underside looking diagonally back and to the opposite side. That big gray thing that is mostly horizontal going across the bottom of the picture is the rear sway bar. The right rear tire is just to the left of the picture. If the FPR on your car is located where you can find it, don't sweat the hose issue. Either take the FPR from your real expensive assembly you bought and replace your busted one, or take a little risk and see if the FPR from one that used to mounted at the fuel rail fits and works. I'll even send you her old one that worked most of the time if you want to try it out (as long as I get it back). If you are getting these same symptoms, I feel pretty sure that the odds are that it is the FPR.

By the way, there is a bunch of missinformation in this thread. My earlier reply should straighten most of them out.

By the way again, if you haven't already figured this out, the FPR is also a check valve. I think most pressure regulators do; its kind of inherent.

On her 850, their is no driveshaft (front wheel drive). Regardless, the hose favors the right side of center and would miss the driveshaft if it had one.

I believe there is only one pump on my wife's 850 which is in the fuel tank. Your car may be like some of the good ole' 740's that have a little one in the tank that I think primes the big one on the underside below the driver's seat near the fuel filter (going from a 740 to a 850 is like going from a kid to an adult in that you only then realize how good you had it).

I hope I answered your questions OK; if not let me know.

I've been ready to get rid of my Volvo's from frustration too (we've got 3; one has been nearly flawless, one a lemon from day one to now, and the 850 started out bad, but has been stellar since then), but there is no other car made that gets reasonable mileage, I can buy used cheap but will be good for several 100000 miles, and is built like a tank (oh the stories I could tell).

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polygaryd · Post by **polygaryd** » 01 Jun 2007, 23:47

on mine the fuel filter and anything resembling that part is behind the right rear tire and very tucked up near the rear axle. very hard to see i am gonna take some pics and put them up here for you to see. i will be under the car sunday taking whatever i can down to figure out where all these lines go. cuz there are the fule lines and then another set of line that i dont know what they go to or what they do.. so many linessss thank you much for the photo i think i know where that part is in the car. i will still take the gas tank down to get to it and all the lines and just to make sure that is what it is... will get back to you..

Post by **Pauloil** » 10 Jun 2007, 20:01

99v70XC same prob for a long time
was told the check valve at the pump was bad and to put key in pos II prior to starting car. this works, but I may have to do it 2-3 times in hot weather. $800 to R&R pumpand fix this.!! The owner's book for this car states it my take 10 sec to start car normally!

polygaryd · Post by **polygaryd** » 10 Jun 2007, 21:22

ok guys i dropped the tank finally since the weather was good. what a pita!!! there is a fuel pressure regulator ABOVE the gas tank. what kind of idiot designed this system?? to get the tank out you have to take the exhaust out as well as the drive shaft and then the lower control arm supports on both sides of the car.. dumb dumb dumb design. took me all day to get the tank down and to get the wires unhooked and out to be able to remove the tank completely now i just have to get the fuel pressure regulator out and replace and reinstalled everything.. way to much work just to replace this small part.. images to come!!!

polygaryd · Post by **polygaryd** » 10 Jun 2007, 21:38

pauloil how long have you had this problem exactly? cuz i had a ford explorer with a bad fuel pressure regulator/check valve since they are the same thing, and it kept blowing through fuel pumps because the pump kept trying to keep pressure in the lines and ends up burning out. only thing that fixed the problem after the 3rd pump went within a year was a fuel pressure regulator and a new pump to match, haven't had problems since. that is why i am trying to get this fixed so not only does the car start right away and not annoy me to death but so the very expensive pump doesn't get ruined i would rather pay 100 for the pressure regulator than 650 for a pump.. you might want to look into getting it fixed soon before the regulator goes completely bad and you have bigger problems!

polygaryd · Post by **polygaryd** » 20 Jun 2007, 21:58

does anyone know how to get the lines off the fuel pressure regulator?? they are like shrink wrapped on or something not like normal rubber lines with clamps or connectors. i really dont want to have to buy the whole assembly from volvo when i can get the regulator from eeuroparts for hundreds less.. sorry bout the photos habing trouble uploading them

Pegs850 · Post by **Pegs850** » 21 Jun 2007, 05:18

polygaryd:

Beware that on the 850's FCP Groton and Euroaparts list the wrong part number. The correct part number includes all of those attached fuel lines. It is possibly the same as for your car. However, if this is the case, I still think you might be able to use the cheaper part.

If it is like the 850's, there are 3 lines coming to the FPR. The smallest is a short engine vaccum line that attaches directly to it and can be removed from the old FPR and used again or replaced entirely with new. Be sure to use hose clamps because bad things can happen (the car checks for vaccum and will as a minimum throw error codes and at worst actually prevent you from being able to start the car). The vaccum line is used to sense the fuel tank pressure (and thereby if you have the fuel cap on) and the the FPR uses it to regulate the fuel pressure.

At the opposite end is the low pressure fuel return line that goes back to the tank. That line has a soft rubber outer protective sheath around the hard plastic fuel line. You can probably cut the entire line if off at the old FPR, remove some of the rubber for an inch or so and slide a piece of tight fitting fuel line over the hard plastic and the new FPR. Be VERY sure to use hose clamps (maybe 2 on the plastic hose side) as I'd be concerned about what would happen if the hard plastic line ever came out, pumping out lots of raw gas. I'd be nervous about trying to use the existing rubber sheath and attaching it directly to the new FPR for a bunch of reasons.

The other "line" is directly from the pump (high pressure) and attaches on the side of the FPR with 2 screws. Be careful to not tear the "o" ring and to keep the crud out. This attachement is a no brainer otherwise.

If yours is dramatically different, maybe send some pics to my regular email address (since you are having problems) and I'll try to help you out.
Dave

Post by **ojdorson** » 16 Nov 2010, 14:23

I've got a '96 850R which takes 5-10 seconds of crank to start. I've got the FPR on the fuel rail.

If I understand this thread right, all I have to do is put a pressure gauge on the schrader valve and measure the pressure at key on (position II) and then watch to see that the pressure is maintained after the key is turned off.

If the pressure drops right to zero, that's a good sign that the FPR is bad, right?