Hello all-

I'm at my wit's end. The vehicle is a 2005 XC70 Turbo AWD.

Original problem (from a few weeks ago): wife drives home one night with everything seeming fine and shuts the car off. Next day, it will crank readily but no start, no run. Weeks of analysis and repair attempts followed.

As of today, July 14, 2020, I have the car in a state where it will start and it will idle/run, but performs poorly under load. I am super frustrated to be only this far but not done after everything we have tried.

Current codes are 0087 Fuel Rail Pressure too low and 2177 Too Lean off Idle (Bank 1). At this point I have done various tests and have replaced the fuel rail pressure sensor, replaced the PEM (and cleaned the heck out of the wiring hookup for it), replaced the fuel pump, and replaced the fuel filter. Here is a running log I have been keeping the whole time since the beginning of the problem, showing my thinking at each phase and the steps taken to get to this point..

Initial symptoms: Car would readily crank but would not start, nor would it run
Battery check: passed
All fuses checked, with particular attention paid to any fuses and relays even remotely related to starting/ignition/fuel. No bad fuses or relays found. Cannot access fuel pump relay without significant removal of parts from fuse box assembly
No CEL or codes present at this time
During testing, occasional message about immobilizer popped up. After reading many forum posts on immobilizer issues, proceeded to test alarm function and manipulate wheel/lock system many ways. No change in result. No further immobilizer messages popped up after initial few instances.
Applying starter fluid through air intake resulted in car starting and running briefly, petering out as starting fluid used up. Conclusion: supports theory of fuel delivery issue.
Next steps:
⦁ removed rear seats and uncovered access to fuel pump and sender unit
⦁ listened to fuel pump with handle of screwdriver, determined that is is at least partially functioning as it makes noises when key put in position 2 and/or start attempted
⦁ Used electrical tester to determine which wires are responsible for sending power and control to fuel pump, checked continuity to wiring harness that feeds PEM module located under car near fuel filter.
⦁ Wired battery power directly to the lines on the fuel pump (bypassing rest of system) to test that. In this configuration the car starts and runs! But it is also evident that without finer controls it does not properly adjust as a normally running full system would.
⦁ Restored original wiring config, removed fuel filter and drained it. A significant amount of fuel spilled from the disconnected lines on both sides and from the fuel filter itself. Blew through filter to test for blockage. No obvious problems found, although filter is very rusty and crappy looking.
⦁ Checked fuel hoses at least where visible, did not see any clear evidence of hose faults, or connectivity problems.
⦁ Under hood, checked Schrader valve at fuel rail (this has been done at various times throughout testing) and only a little bit of fuel poured out weakly.
⦁ Visual inspection of fuel rail pressure sensor did not reveal any obvious faults.
Theory: Not enough fuel being sent to fuel rail
Next steps:
⦁ Tried simply adding more fuel to tank after reading that sometimes sender unit does not properly read fuel level (gauge indicates over half full) and therefore may send bad info. No change in results
⦁ Visual inspection of PEM module showed it to be very old and corroded-looking, and the wiring plug into it is not in ideal shape either.
⦁ Replaced PEM module. After this replacement, the car will now start and run. However it runs inconsistently..seems fine for a minute, then runs rough then fine again. Road test proved that although car will now start and run, it is not dependable and performance under load is erratic at best. It will always start and run again but every time it runs unreliably.
⦁ At this point CEL came on and codes were thrown. Initial result was two codes:
⦁ P0087: Fuel rail pressure too low
⦁ P0088 Fuel rail pressure too high
⦁ Despite (or maybe due to) directly contradicting codes, determined that next thing to try was to replace fuel rail pressure sensor.
⦁ Cleared codes and replaced fuel rail pressure sensor. Initial results seemed better, but further testing showed a return to inconsistent performance. Now only one code though: P0087 Fuel rail pressure too low
⦁ Tested wires at connector on top of fuel tank, seems ok, shows voltage when key put to position 2
⦁ Tried a configuration with old PEM and new fuel rail pressure sensor. Result: Car would sometimes fail to start, and when it did start performance was consistently poor. So I re-installed the new PEM (Theory: New PEM with new shiny pins helps some but maybe connector itself is corroded enough to cause inconsistent performance even though car will now start and run (albeit inconsistently)
⦁ Acquired and used electronic cleaner to attempt cleaning of female plug that connects to the PEM. Performed two rounds of cleaning to extent possible, allowed to dry, reconnected and tested car. Same result. Will start and run but performance is inconsistent and suffers under load.
So with these summarized facts (this was about a week ago before I replaced the fuel pump itself):
1) when fuel pump is connected directly to battery, car started and ran
2) after reconnecting everything with normal wiring config, then replacing the fuel filter, the PEM and the fuel rail pressure sensor, the car will now start and will run but performance is inconsistent and still getting code P0087 "Fuel rail pressure too low"
3) Clearly fuel pump works at least partially, despite the current condition of inconsistent performance because otherwise it would not start and run at all given everything above
My thoughts at this point - Do I still go ahead and replace the fuel pump itself? Before plunking down that additional $200-300 and embarking on what kooks like a fairly hard and sketchy job of replacing the pump itself...Should I try (even though I already replaced both PEM and Fuel Rail pressure sensor (and filter) to take the sensor out of my other, working, XC70 and see if that helps (maybe I got a bad new sensor)?Or am I missing something else here?

My experience sounds a lot like this guy (although I do not have the tools to test the actual fuel pressure number): https://www.volvoxc.com/forums/archi...p/t-27514.html
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UPDATE 07/13/2020
Replaced fuel pump. Connector for wiring had correct pins but had to be slightly filed down to accept the plug. Thought plug was fully inserted after file down.
Initial test: back to square one...would crank readily but no start, no run and a whining noise from engine compartment (electrical sound). Pressed wiring plug harder into fuel pump and it clicked in. Tried again.
Sudden fuel spray inside car...the send hose from the fuel pump's outward tube (on top of pump) had come off, almost as if once plug inserted all the way it was too powerful, or maybe when we replaced the pump we just hadn't attached it fully and it did not reveal itself until plug properly connected.
Ensured hose fully connected, cleaned up, prepared to test again.
Car started and ran. Did not die, idled normally. Tried to drive away.
On this run and all following runs, it seems ok under load for like the first 30 seconds but then after pulling onto road and trying full acceleration, it always seems to struggle under load. Was able to limp it around, got to a parking lot, let it idle a while. Revving while in park works perfectly every time.
Cleared codes, restarted car. Drove again. Again, seems fine for like 30 seconds then starts to suffer under load, sometimes recovers, sometimes dies. Will always restart fine every time.
Checked codes again, now it is a laundry list:
0087 Fuel rail pressure too low (x2)
2177 System Too Lean Off Idle Speed
0300 Random/Multiple Cylinder Misfire
0301 Cylinder 1 Misfire
0302 Cylinder 2 misfire
0304 Cylinder 4 Misfire
0303 Cylinder 3 Misfire
Limped it home and parked for the night.

Today I even tried putting the old fuel rail pressure sensor back in. It did not help, so I re-installed the new one. I am about ready to give in and go to a mechanic but after all this work it seems like a failure to do so and get charged for the mechanic to probably repeat everything I already tried. I also looked for literally an hour to see if there was some obvious broken hose or wire, nothing like that found...I can see a few spots throughout the car where previous "mechanics" cheesed the process of removing or replacing things and broke little clips and things, but no obvious culprit. I cannot for the life of me figure out the last stage location of where the fuel actually gets into the fuel rail itself (suspecting at this point because I have replaced almost everything leading up to that point in the chain maybe I have a blockage or something between the filter and the fuel rail somewhere?) but I cannot see anything obvious and don't want to disassemble half the motor to find out. SOme people mention fuel pressure regulators but I'm not sure this model even has one (apart from the already-replaced sensor) and if there is such a thing I sure can't find it. Frustration is at peak level.

Does anyone have any ideas?

 

A few thoughts - you could have a pinched line or perhaps a return flow or tank venting issue. Found this which may have some insights for you on how the end to end fuel system lays out.

https://www.matthewsvolvosite.com/fo...ic.php?t=23441

 

Thank you for sending this mt6127, I will study the diagrams and go out and look again. In the meantime I would still appreciate any more thoughts you or anyone else has, I am still in the fight

 

Don't know the differences in the engines year to year to know for sure so...

Does your car/engine have a fuel pressure regulator at the fuel rail? Return line from the fuel rail to the tank?
Possible issues with the fuel regulator if there. If there is a fuel return line from the engine to the tank with a "rubber" line try pinching it off/restricting the return flow to see if there is a difference in the engine running.

 

2004 Volvo xc70 wagon 2.5 litre 5 cylinder turbo engine 265,000 km. I am having a low fuel pressure delivery problem 20 pisg read at the fuel rail connection in the engine compartment, with the key on then the same pressure as cranking but start and stopping right away. I was told by Volvo parts dealer there is a fuel pressure sensor on the fuel rail part # 31272730 and it even shows its should be there as per the fuel delivery diagrams they sent me but there is no fuel pressure sensor on the fuel rail . I am having also trouble finding my PEM fuel control module part# 30742823, my car has a plastic- rubberized type coating gas tank with some kind of protection panels around it. I have looked in the spare tire battery compartment for it not there, I did get the car started last week in the driveway and the fuel rail pressure would not go above 32 psig, but after shutting engine off now back to 20psig fuel rail pressure and a no start condition. I have tried a few times taking negative cable off battery overnite to reset computer this has not helped, I would much appreciate any help suggestions here, thanks, James

 

If you don't have a fuel pressure sensor mounted on the fuel rail as pictured below - you don't have a PEM. That means your fuel pump runs at full speed all the time. (at least is is supposed to when it's good). You have a canadian car and perhaps the older style fuel system without a fuel pressure sensor was/is still sold there. Perhaps you simply have a bad fuel pump after 18 years. I don't know the correct part number - so I would call my local dealer and ask them for price,availability and part number using your VIN. Then you can make a decision on how to proceed and who to purchase a part (if needed) from. If you replace the pump be sure to get new orings for both sides of the tank - you'll have to open both left and right access ports. Some have reported finding foreign material in their tanks that damaged the new pumps they just put in - so I would make sure there is only pure gasoline in the bottom of your 18 year old Volvo gas tank.

 

As someone else posted maybe you have a different version with no fuel rail pressure sensor...but as for the PEM...one of my XC70s had it in the spare tire/battery compartment...BUT, the other one had it located under the car right near the location of the fuel filter, so look there if you haven't already. It's a black plastic object with a wiring harness, like a 4" square.

 

Thank you all for the replies here and to Volvo forums, especially to hoonk senior member for sharing his knowledge with me and all of us. He nailed it, if there is no fuel pressure sensor on fuel rail as in my case then there is no fuel pump control module. Until I posted this and got his reply. I looked everywhere for the PEM module. I installed new fuel filter and battery in spare tire compartment last summer and the car ran better up until the last few months ago then keep getting worse. I will be first replacing fuel pump relay under drivers side bottom access and see if the fuel pressure comes up to specs, I believe should be around 60PSIG at the engine fuel rail not the 20 PSIG I have been getting, and then see if car runs okay. If not remove back seats and check fuel pump wiring connections and see if the pump is getting the full 12.7 VDC battery voltage when key on and cranking or the 14.3 VDC with engine running that is also measured at the battery and replace fuel pump if needed. Does any one have the Volvo fuel rail pressure specs for my cars fuel delivery system? that I should have with key on, cranking and engine start running? I will keep the forum updated as to my repair status, thanks again, James.

 

I have a similar issue, and share your pain - 2005 XC90, 2.5T, in California. Starts and runs perfectly for 20-30 minutes. Then under moderate acceleration, instead of steady climb in rpm the engine stumbles around 2500 rpm, stumbles, stumbles, then finally "kicks in" and jumps up to 3000 plus. Runs great the rest of the time. Code 0087 - checked fuel pressure at Schrader valve, all OK. Replaced fuel rail pressure sensor anyway, no change in performance. Replaced fuel pump (what a pain!) and filter - no change in performance. Replaced throttle body - no change. The problem only occurs after 20 to 30 minutes; once everything is good and warm. I think the only other components are the fuel pup control module and the gas pedal. Before I try those, does anyone have any ideas?

 

I wonder - could it be as simple as the fuel pump relay (under the hood, I think). In my case, perhaps the relay acts wonky once the under-hood temperature gets hot. After 190K miles, I suppose it wouldn't surprise me that it could be that simple. I will try it and see...

 

Was this the issue? I think i might have the same issue you have.

 

- there is no fuel pump relay in a 05 2.5t xc90. There is a relay for the fuel system under the hood on the xc90. (if equipped) That relay is for the Bi-fuel lpg/gas cars only.

 

To update this forum ,hoonk senior member diagnosis was correct on the fuel pump causing low fuel rail pressure problems and thanks again to him for sharing his knowledge with us. I am still having a strange problem with this cars engine that when the car first starts it idles fine in park and when put into drive it idles fine but when I step on the gas pedal it hesitates for about 5 to 10 seconds then picks up fine and runs great with no more hesitation as long as the engine is not shut off. if I start the car again it does the exact same thing everytime. I recently also replaced the 5 ignition coils and plugs with no change to this problem, does anybody have any suggestions here?