Fix P0087: Mechanic’s solutions that WORKED

The code P0087: Fuel Rail/System Pressure – Too Low points out a fault in the vehicle’s fuel system, specifically indicating that the fuel pressure in the rail or system is too low. This issue is most likely caused by a fuel delivery problem, such as a weak pump, clogged filter, or a fault within the pressure regulation components.

P0087 quick overview

Meaning	P0087: Fuel Rail/System Pressure – Too Low
Is it serious?	Yes, it can lead to poor engine performance, and in some cases, the vehicle may go into a limp mode or stall.
Possible causes	– Blocked fuel filter – Weak fuel pump – Leaking or clogged fuel injectors – Faulty high-pressure fuel pump – Compromised fuel lines – Defective fuel pressure regulator – Faulty fuel rail pressure sensor – Incorrectly installed or failing high-pressure relief valve
How to diagnose?	Check for additional codes to identify if there are related issues. Inspect fuel lines and filters for blocks or leaks. Test the fuel pump to ensure it’s providing the correct pressure. Examine the fuel injectors for proper operation and return rates. Evaluate the fuel pressure regulator and its performance with a scan tool. Check the fuel rail pressure sensor for accurate readings. Ensure proper installation and torque of the high-pressure relief valve.

When you see this code, it means your car’s engine isn’t getting enough fuel pressure to run correctly. This could be because something is blocking the fuel from getting through, parts that push the fuel are weak or failing, or sensors that monitor the fuel pressure aren’t working right. It’s important to fix this because it can make your engine run poorly or even stop it from running altogether.

How to fix P0087 – learn from mechanics

I looked into P0087 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Land Rover

Vehicle information 2012 Land Rover Range Rover Sport HSE 5.0L

Issue + repair history

• MIL Lamp on, Long crank, P0087 stored intermittently
• Truck runs rough, restricted performance light on, loud ticking from engine
• Replaced high pressure fuel pumps and tappets
• Found and removed fuel filler flap from tank, replaced fuel pump, same issue persists
• Replaced high pressure fuel sensor, issue remains

What are people suggesting to fix issue

• Perform V Drop testing on the in-tank pump power and ground
• Check low pressure sensor or wiring at the sensor
• Consider injectors might be sticking open, causing misfires and long crank
• Clean fuel injectors with BG upper intake cleaner
• Check Fuel Pump Driver Module for damage
• Clean or replace fuel injectors, especially considering vandalism history
• Blow out and clean fuel lines all the way to the injectors
• Check for damaged or chafed wiring
• Verify fuel pressure readings, check for leaking injectors
• Check timing of the high pressure fuel pumps

What was the final fix

• The pump timing was off. Adjusted the timing of the vacuum pump.

Case #2: Ram

Vehicle information 2014 Ram 2500 Lone Star 6.7L

Issue + repair history

• Loses power under load, especially when towing and hot
• Codes P0201 to P0206 and P0087 present
• No previous repair history mentioned

What are people suggesting to fix issue

• Check if P0087 can cause the injector circuit codes
• Suggested that P0087 (low fuel pressure) usually indicates a restricted fuel filter
• Suggested measuring fuel volume at the CP3 high-pressure pump inlet
• Check fuel-supply pressure and volume, especially at wide-open throttle
• Consider possible contamination due to water in diesel or gas in diesel after a storm
• If equipped with a tuner, return to stock settings, clear codes, and retest

What was the final fix

• In-tank fuel pump was faulty, only supplying 7 psi
• Replaced in-tank pump, which resolved P0087 and power loss
• Injector circuit codes (P0201-P0206) have not returned
• A TSB suggested reflash of PCM to change injector circuit codes from 1 trip to 2 trip codes
• Injector codes may have been set due to extended cranking and low battery voltage

Case #3: Chevrolet

Vehicle information 2002 Chevrolet Silverado 2500 HD 6.6L

Issue + repair history

• Truck arrived not starting, towed in
• Low fuel pressure observed (2 MPa when 40 MPa was requested)
• Primary fuel pump replaced, as it was sucking air
• Injection pump replaced (prematurely, as later realized by the technician)
• Identified faulty injector by capping off injectors one at a time
• Replaced all injectors on the affected bank
• After repairs, vehicle starts but with actual fuel pressure pegged to maximum

What are people suggesting to fix issue

• Verify if the issue is high fuel pressure (P0087 is low pressure, while P0088 is high pressure)
• Monitor the Fuel Rail Pressure (FRP) with the Key On Engine Off (KOEO) to check if it’s within normal range
• If FRP is correct KOEO but goes high after starting, the Fuel Pressure Regulator (FPR) could be the issue
• Use a scan tool to command various pressures and compare actual vs. desired FRP
• Check for high pressure leaks if there is a significant difference between commanded and actual FRP
• Suggesting that the Fuel Control Actuator (FCA) or its connection could be at fault
• Check for pinched return lines or issues with the fuel regulator on the injection pump
• Ensure there are no blockages in the fuel return lines

What was the final fix

• Technician had a code P0089 (not P0087), which is for high fuel pressure
• An open in the electrical system related to the injection pump fuel regulator was discovered after re-evaluating the work done
• One of the wires had partially pulled out of the regulator connector
• Reconnecting the wire properly solved the high fuel pressure issue

Case #4: Audi

Vehicle Information: 2007 Audi Q7 3.6L

Symptoms:

• Poor idle quality
• Misfire
• MIL (Malfunction Indicator Lamp) on

Diagnostic Trouble Codes (DTCs):

• P0087: Fuel Rail/System Pressure Too Low
• P0300: Random Misfire
• P0305: Misfire Cylinder 5
• P0304: Misfire Cylinder 4
• P0420: Catalyst System Efficiency Below Threshold Bank 1
• P0430: Catalyst System Efficiency Below Threshold Bank 2

Related Repair History:

• High-pressure fuel pump and fuel rail pressure sensor replaced by an Audi dealership
• Timing chains and high-pressure fuel pump replaced by an independent repair shop

Community Replies:

1. For P0087 in Conjunction with Camshaft Position Codes:
   • It’s advised to check for camshaft position-related codes (like P0016) first. If such a code is present, the issue with fuel pressure may be due to incorrect cam timing from a faulty camshaft solenoid. Addressing the camshaft position code could resolve the P0087 code.
2. Concerning Previous Timing Chain Service:
   • It is recommended to verify the engine’s timing, especially if the timing chain service was previously performed. Incorrectly set timing can lead to misfire codes and poor engine performance.
3. High-Pressure Fuel Pump Cam Lobes Inspection:
   • Based on experience with similar engines, inspect the cam lobes that operate the high-pressure fuel pump and their followers for wear. Excessive wear in this area could result in low fuel pressure issues.
4. Checking Fuel Supply and Cam Timing:
   • Ensure the low-pressure fuel supply is adequate by checking the pressure from the fuel tank’s pump.
   • Verify the camshaft timing by reviewing specified vs. actual values in the engine control module’s Measuring Value Blocks for both the exhaust and intake cam timing. Discrepancies here could indicate timing issues.
     
     The customer didn’t want to spend money on the vehicle and sold it, no fix is known.

Case #5: GMC

Vehicle Information 2008 GMC Sierra 2500 HD WT, 6.6L engine

Issue + Repair History

• MIL Lamp on with OBD2 codes P0087 (fuel pressure too low) and P0088 (fuel pressure too high).
• Initial actual fuel pressure was 80 MPa, with desired at 160 MPa.
• Injectors 6, 7, and 8 were replaced due to excessive return rate.
• High-pressure fuel pump replaced.
• Customer mentioned a plug was installed instead of a high-pressure relief valve at another shop, which was then replaced with a factory valve.
• Another replacement of the high-pressure relief valve was done, but the issue persisted with the vehicle entering reduced power mode under load.

Community Suggestions

• Replace the entire fuel rail including the pressure relief valve.
• Ensure the high-pressure relief valve is tightened properly due to its steel-on-steel sealing surface.
• Apply assembly lube or clean engine oil on the sealing surface of the valve during installation.
• Check the fuel rail pressure regulator (FRP) and listen for changes in engine tone when commanding fuel pressure changes with a scan tool.
• Ensure proper torque on the pressure limiting valve.
• Examine the fuel pressure regulator for signs of metal, which may necessitate replacing the pump and fuel rails.

Final Fix Properly torquing the high-pressure relief valve resolved the issue, aligning desired and actual fuel pressures.

Common Advice	Description of Diagnostic Step
Torque the high-pressure relief valve properly	Ensure the valve is tightened to the manufacturer’s specifications to prevent leaks and improper pressure readings.
Check the high-pressure relief valve for proper installation	Verify that the valve is not faulty and that it is installed correctly, without substituting a plug.
Replace the entire fuel rail if needed	If issues persist, consider replacing the fuel rail which includes the factory-installed pressure relief valve.
Use proper sealing techniques	Apply assembly lube or clean engine oil on the sealing surfaces to prevent leaks.
Test the fuel rail pressure regulator (FRP)	Use diagnostic tools to command changes in fuel pressure and listen for engine tone changes to ensure the FRP is functioning.
Inspect for metal in the fuel system	Examine components like the fuel pressure regulator for metal debris, which could indicate the need for further replacement of parts such as the pump and rails.