Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy your stuff using this and it helps MVS!

XC90 V8 Intermittent fuel pressure cutout (kinked fuel pump line) Topic is solved

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
User avatar
Posts: 41
Joined: Wed Jan 03, 2018 1:23 pm
Year and Model: 2007 XC90V8S
Location: IRVINE, CA
Has thanked: 24 times
Been thanked: 3 times
United States of America

Thread is getting too long...

Post by SHOCKWAVE » Wed Apr 04, 2018 3:35 pm

I meant replacement by Volvo since I took it in...I'll wait til this is resolved before posting again to avoid adding confusion (unless I need SPECIFIC help). Fuel pump was omitted by everyone as it had been replaced and assumed good- it wasn't


PO (previous owner-2nd owner, 120k to 150k, no records of anything done by 1st owner (0k -120k))-
-Unknown Indy Replaced FP in March '17 (report was of car dying on freeway)
-Took into Volvo June '17 (replaced FP and Fuel Filter). Indy's insurance paid for most of this. I don't know why they punted to Volvo to do a second replacement.
PO SUMMARY: Two fuel pumps and one fuel filter installed

ME (shockwave)-
-Bought in NOV '17 (not knowing about fuel issue)
-Cutting out started after a few days of driving
-Replaced Fuel Filter, Spark Plugs, Air Filter, Fuel Pressure Sensor
-Continued to have issue sporadically
-Replaced PEM
-Still had pressure issue/driveability
-Electrical diagnosis with abscate
-Took into Indy for inspection- They indicated everything looked good except for there's probably something in the tank causing the loss of pressure
-I opened up fuel tank to inspect pump- found kink
-Took into Volvo on Thursday hoping for a warranty replacement
-Who knows what they are doing at this point...I've been trying to let it play out...

Fuel Pump has to be replaced or that hose has to be fixed before proceeding.
These users thanked the author SHOCKWAVE for the post:

2007 XC90 V8 SPORT 151K

User avatar
Posts: 41
Joined: Wed Jan 03, 2018 1:23 pm
Year and Model: 2007 XC90V8S
Location: IRVINE, CA
Has thanked: 24 times
Been thanked: 3 times
United States of America

Oh Boy...Update...

Post by SHOCKWAVE » Thu Apr 05, 2018 4:25 am

UPDATE: (no grammatical fixes)
Volvo (2:25PM): We need to put $20 to road test vehicle
Shockwave (2:30PM): Roger that
Volvo (5:30PM): The fuel pump has to much pressure. Should know tomorrow. Thank you for your continued patience.
Shockwave (5:35PM): Ok, keep me posted.
Shockwave (5:36PM): I assume that is a new fuel pump?
Volvo (6:45pm): We are still in the diagnosis phase . The wrong fuel pressure sensor allowing over 9-13 pounds of pressure can damage the fuel pressure re-leaf valve which is internal with fuel pump. We will be testing the pressure tomorrow. "If the fuel pressure re-leaf valve is good on the Volvo Diagnostic tree. Problem could be internal in ECM "Engine Control module" this is why you are coming up with Code Pressure sensor which is connected directly to ECM.

:shock: :shock: :shock: :shock: WHAT? I know the service rep doesn't understand what he's talking about, but c'mon. The techs should know better...

(1) The problem existed before and after the sensor replacement.

(2) Volvo documentation shows them to operate identically, 0-5V, ECM stability is at 480 kpa. ECM uses FPS + Patm to get it's value. As long as the FPS and ECM value are in agreement at 480kpa, duty cycle remains at around 45%. We've discussed this ad nauseum. Also, ggleavitt cordially provided the below link on my sister post at swedespeed
(http://forums.swedespeed.com/showthread ... nstability):

http://forums.swedespeed.com/showthread ... -and-parts

(3) The pressure "RE-LEAF" valve is set to open at 650kpa (94.3 psi). Even if what he said is true, gage pressure in the fuel line would be:
380kpa (55psi) + 62kpa (9psi) to 90kpa (13psi) =
442kpa (64psi) to 470 kpa (68psi).
Further, even if that valve opens, that would reduce fuel line pressure. I concede if the relief valve opens without engine braking, there could be issues. But that's putting the cart before the horse. No reason to go down that route. Onset is always falling fuel pressure, with the ECM increasing duty cycle to catch up. Also, the end result is engine dying from fuel starvation. If that relief valve opens, it supplies fuel to the pump, but pressure to the engine would be reduced.

"The by-pass valve also functions as a non-return valve, ensuring that the fuel pressure in the system is maintained when the engine is switched off.
There is high pressure before the engine is started. This high pressure means that the valve in the by-pass valve opens and the system is "flushed". " Maybe that partly explains why it can recover sometimes by shutting it off...

(4) How is he going to test the pressure "RE-LEAF" valve on the Volvo Diagnostic tree? It's a mechanically spring loaded relief valve. Only way to test that is to apply it's cracking pressure (+650kpa). I guess he could apply full voltage to the pump. :roll: :roll: :roll: :roll:

(5) "Problem could be internal ECM? That is why..." WHAT? That makes no sense...If the pressure is out of range of course the ECM is going to throw a fault. If he means the ECM is unable to interpret the signal from the FPS (0-5V), it's ironic that there's a heavily kinked fuel line at the same time (tongue in cheek). And why does the signal work for almost exactly 14-15 miles at different temperatures (low/high)? And why does it take much longer (45 min) if it is sitting at idle to get it to have low fuel pressure. Could it be that the reservoir is not being replenished? No, couldn't be that... :roll: :roll:

Factory dealer service is AMAZING! They are going to fight me tooth and nail on this...I'm surprised they even actually asked for a picture of the kinked hose. All this over $300...hopefully my bottom lip is still intact after this because I'm biting it pretty hard!

2007 XC90 V8 SPORT 151K

User avatar
Posts: 41
Joined: Wed Jan 03, 2018 1:23 pm
Year and Model: 2007 XC90V8S
Location: IRVINE, CA
Has thanked: 24 times
Been thanked: 3 times
United States of America


Post by SHOCKWAVE » Fri Apr 13, 2018 2:29 pm

I picked up the car on Saturday and having been driving it since without issue... :D :D :D


VOLVO would not proceed unless I had them replace the sensor ($120). I conceded in order to get the car back. They tried to charge me for the diagnostic, but I reminded them that the agreement was that if the fuel pump was faulty, the diagnostic would be waived. So it cost $120, versus me having to replace the pump myself @ $300+. They were nice and friendly, but they took 9 days to get the car back to me. That is not very good service. I was also kept in the dark most of that time despite various inquiries. However, they did replace it under warranty. Volvo website indicates part warranties are non-transferable. No indication of that on the original receipt so I thought it was worth a try. Maybe it's a law in CA or something...At any rate, one reason to avoid the dealer at all costs if you can. The final resolution was acceptable, but it was a stressful 9 days. I was tempted to tell them to button it up and forget it because I could fix it in an hour or less...enough on that.

Software was up to date already.

I picked up some parts at a boneyard while my car was in the shop: Fuel Pump ($31), Foam under seats ($10/both), PEM ($10), Fuel Hose to filter ($3), turn signal stalk ($12). Mainly I wanted the fuel pump in case I decided to fix the kink hose. I've updated my schematic accordingly, as a few things were incorrect. See below.

HERE'S A SUMMARY OF HOW TO DIAGNOSE THE DECOS P2 FUEL DELIVERY SYSTEM (Air supply and delivery at the rail are assumed to be good). There are other methods, but this is what I would do. I assume no liability and perform at your own risk.
  1. Check codes:
    Follow the codes to get the particular error resolved- typically this just requires replacing the FPS. See below for more info on the FPS.
  2. Check fuel pressure:
    1. Manually checking a fuel gauge is better as a first step but the Schrader valves are not in the best positions. I had a coolant hose clamp in the way of the one on the rail. If a known good FPS is installed, VIDA or OBD scanner can be used to check the value
    2. Fuel Pressure Values:
      • Gage pressure should be 380 kpa (55psi)
      • FPS value in VIDA (and typically OBD tools) report as absolute pressure: gage + atm = 380kpa + 101kpa = 480 kpa
      • ECM value in VIDA does the same. Atmospheric sensor is on top of the ECM which is on top of the air box
      • It is normal for fuel pressure to vary with engine load. Fuel pressure should hold after the key is cycled off.
  3. Check FPS (7/156) Electrial: Note values have not been completely verified as the calibration of the FPS is unknown (proprietary to BOSCH)
    • Signal to ECM is the Blue Wire (0-5V): (#A71 at ECM), 2.4V at startup, then 1.8V to 2.1V at idle
    • Supply Power is Violet Wire (5V): (#A47 at ECM)
    • Ground is the Brown Wire: (#A14 at ECM)
    • [Fuel Temperature Signal is the Green Wire: (#A46 at ECM)]
  4. Check PEM (4/83):
    1. Power Supply - CEM to PEM (#A16 at CEM)- (Blue Wire into PEM): ~14.0 V
    2. Command Voltage from ECM to PEM (#B20 at ECM) ((Yellow Wire into PEM): varies depending on the ECM command. Mine was around 7-8V. PWM signal so there must be a PWM circuit in the ECM for this.
    3. Pump Control - Amperage from PEM to Pump (6/33) (Black w/ White Wire out from PEM): 2.0 amps (idle) to 8.0 amps (full load)
    4. Note: Ejector Pump (6/31) runs off Blue Wire from ECM at full voltage (14.0). Branched off of the wire that supplies power to the PEM.
  5. Check Pump
    1. Check Venturi Pickup For Obstructions (Yellow with White Guard on Bottom; Connects to Level Sender which is spring loaded to keep it on the floor of the fuel tank
    2. Check Fuel Pump Lines for Kinks
    3. Replace Pump Assembly- Anything else wrong with it would be very difficult to diagnose. This is why it is sold as an assembly.
Final Notes:
  1. Plastic Tank- Magnets won't help with debris. Some models have metal tanks. You'll have to research that for the application.
  2. Component designations: (xx/xx) - First component is the system, second is the serial. e.g.- 6/33 is the pump. 6 represents an electric motor and 33 is just the number of the component.
  3. Accessing the fuel pump is much easier than you'd think.
    1. Remove driver and passenger seats. Remove the covers by popping them free (up in rear and forward in front). You can remove the center seat, but make sure to disconnect the battery first. Wait for 10+minutes, and then disconnect the orange connector under the seat. Each seat has 4 screws. Tie up each side of the floor to the center seat using a bungee.
    2. Break the foam pieces under the seats. (Not necessary if you remove the center seat. Just take them out). Remove the smaller foam piece running behind.
    3. Remove passenger side duct
    4. Cut an access flap in the pump side floor lining the size of the cover.
    5. The rest should be easy enough other than the lock rings. Those require a special tool (Schley 69800) which I recommend buying ($35). You can make one, but I don't think it is worth it and you need to torque them back correctly (@ 60 Nm).
    6. Make sure to tie a line on the level sender side hose before pulling the pump out. You use this line to pull the new one back through to the driver side.
    7. I don't think it is necessary to completely remove the fuel, but this makes the operation more risky. Keep yourself grounded and don't make any sparks. 1/4 tank is fine. I siphoned the fuel once there was access, but when I replaced my E46 fuel pump last week, the tank was full. You just have to be smart and careful!!
PEM-DIAGNOSIS- Volvo V70 R - 2003 - Fuel Pressure Fault_.pdf
(352.13 KiB) Downloaded 119 times
These users thanked the author SHOCKWAVE for the post:

2007 XC90 V8 SPORT 151K

User avatar
Posts: 327
Joined: Sun Jun 04, 2006 11:33 pm
Year and Model: XC90 05-2.5T, 08-V8S
Location: Seattle
Has thanked: 0
Been thanked: 44 times
United States of America

Re: XC90 V8 Intermittent fuel pressure cutout

Post by ggleavitt » Fri Apr 13, 2018 3:47 pm

So was pump plus the FPS (since the shop insisted on it).

Glad you got it sorted out (really happy for you).

Now onto getting it to handle like a Sport. I have a list of the parts required for a front end rebuild specific to the Sport-RD, contact me and I'll send it to you so it's all in one spot. Same for V8 valve covers if they ever need done.


*edit- add words
These users thanked the author ggleavitt for the post:

2005 2.5T AWD-195k
2008 V8 AWD Sport-125k

User avatar
MVS Moderator
Posts: 17888
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 192 times
Been thanked: 619 times
Trinidad & Tobago

Re: XC90 V8 Intermittent fuel pressure cutout

Post by abscate » Sun Apr 15, 2018 4:32 am

Great persistence and kick a$$ methodical troubleshooting. It’s great to find an artist who is also an engineer.

Good luck with the next life transition and enjoy those kids...they grow fast
These users thanked the author abscate for the post:

Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW

User avatar
Posts: 41
Joined: Wed Jan 03, 2018 1:23 pm
Year and Model: 2007 XC90V8S
Location: IRVINE, CA
Has thanked: 24 times
Been thanked: 3 times
United States of America


Post by SHOCKWAVE » Thu Apr 19, 2018 8:57 am

Thanks guys. Would have been a much more difficult/stressful road without the help from these boards.

ggleavitt -I'll follow up. I'm back to Day 1 of R/R on this vehicle...Rides nice, but needs long term restore.

To put a face to a name so to speak...
IMG_1934_rotate.jpg (132.33 KiB) Viewed 705 times

2007 XC90 V8 SPORT 151K

Posts: 6298
Joined: Fri Nov 12, 2010 9:25 am
Year and Model: 2004 V70R GT, et al
Location: Ponder Texas
Has thanked: 2 times
Been thanked: 154 times

Re: XC90 V8 Intermittent fuel pressure cutout

Post by jimmy57 » Fri Aug 10, 2018 11:44 pm

Sorry I didn't see this one earlier. I applaud all the hard work and methodical troubleshooting and documentation.
This issue is not too uncommon when FP is replaced. Dirt gets into tank and the dirt/silt plugs the membrane filter on bottom of pumps in the fuel pump cup. Letting the car sit lets the dirt fall off when suction is gone.
Multiple fuel pump replacements fixes it. Removing tank and washing it out and then replacing pump or disassembling the existing one and cleaning the membrane filter will fix it. I have seen the pump moved to another car and have no issues like you reported. The dirt in the tank is cumulative with some getting through membrane. When there is still dirt in tank then it takes time for it collect enough to starve pumps and the PEM current to ramp up at command of ECM. PEM can get hot and shut down and kill the car sometimes. This is a KILLER problem the first time you have it. It is spotty as some areas have no dirt roads or the car is not driven on dirt roads. It is not a sign of a less than clean tech doing the work. It is a result of the sender and sender/pump unit being low spots and the retainer rings having a great place to hold dirt that is hard to blow out prior to pump removal. air blower and at the same time using a shop vac seems to gt the area clean.
These users thanked the author jimmy57 for the post:

Post Reply