Fuel Pressure Issue H3 Alpha with Codes
I have a 2009 Alpha(5.3 V8) with just shy of 100k miles. I bought it about a thousand miles ago, and I guess they hid this code well enough I wouldnt know. I believe, worst case, it's a fuel pump replacement. Here is the issue.
P0451 Evaporative Emission System Pressure System/Switch Range/Performace P0191 Fuel Rail Pressure Sensor A Circuit Range/ Performace P069E Fuel Pump Control Module Request Malfunction Indicator Lamp Illumination Occasionally on start up, and only after sitting still overnight/a long time, the hummer will rough idle for 10-15 seconds. I assume that its low low fuel pressure. Driving I never see an issue, it never misses and I dont believe there is a loss of power. I have a code reader I can use when driving and it will also show live data from the sensors. It shows that no matter the throttle or engine RPM, I have 44 PSI. never higher, never lower. Thinking that maybe its a bad sensor, I hooked up a fuel pressure guage to the fuel rail to see if the sensor was bad, and they both read 43-45 PSI. When the throttle is depressed, the pressure guage needle will quiver, but not increase. I dont want this to be a whole fuel pump replacement, and I think that if fuel pressure never goes up, maybe the pressure relief valve is stuck open? I have got the hummer on a lift and done a full visual inspection of the fuel lines from the tank to the fuel rail, and I did not see any leaks. There is no fuel on the ground when parked, I dont believe there is a leak in the system. There is no "Lean Fuel" code. Any suggestion on my next troublshooting step? |
Fuel Pressure Fuel Pressure (Key ON, Engine OFF)380-410 kPa (55-60 psi)
Relieving Fuel Pressure Caution Caution: Remove the fuel tank cap and relieve the fuel system pressure before servicing the fuel system in order to reduce the risk of personal injury. After you relieve the fuel system pressure, a small amount of fuel may be released when servicing the fuel lines, the fuel injection pump, or the connections. In order to reduce the risk of personal injury, cover the fuel system components with a shop towel before disconnection. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.
Fuel System Diagnosis Diagnostic Instructions
Circuit/System Description The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON. The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel tank module, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions. The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel tank module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter, contained in the fuel tank module, and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel tank module. The function of the venturi pump is to fill the fuel tank module reservoir. The fuel pressure regulator, a part of the fuel tank module, maintains the correct fuel pressure to the fuel injection system. The fuel tank module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times. Reference Information Description and Operation Fuel System Description (See: Computers and Control Systems\Description and Operation\Fuel System Description) Electrical Information Reference
Scan Tool Reference Control Module References (See: Testing and Inspection\Programming and Relearning) for scan tool information Special Tools
Circuit/System Verification Important:
¤If the fuel pump does not operate, refer to Fuel Pump Electrical Circuit Diagnosis (See: Computers and Control Systems\Testing and Inspection\Component Tests and General Diagnostics\Fuel Pump Electrical Circuit Diagnosis) .
Important:
¤If the fuel pressure is greater than the specified range, replace the fuel tank module. ¤If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank module.
¤If the fuel pressure decreases more than the specified value, perform the following procedure:
¤If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s). ¤If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the fuel tank module.
¤If the fuel pressure decreases more than the specified value, replace the fuel tank module.
¤If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank module.
Repair Instructions Perform the Diagnostic Repair Verification (See: A L L Diagnostic Trouble Codes ( DTC )\Testing and Inspection\Verification Tests) after completing the diagnostic procedure.
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Did you ever figure it out? My h3t is getting that p069e code. Stalled out on me at a stop sign and would crank but wouldn’t start. Thought it was the pass lock but then it started working fine.
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Originally Posted by daniiel777
(Post 364177)
Did you ever figure it out? My h3t is getting that p069e code. Stalled out on me at a stop sign and would crank but wouldn’t start. Thought it was the pass lock but then it started working fine.
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UPDATE:
After cleaning the throttle body, visually checking all the fuel lines and fuel rails, I had no difference in the Codes or Startup-idle issues. I decided that it was easier to replace the whole fuel pump, considering on my 2009 h3 alpha, the pressure regulator, and pressure valve are included in the fuel pump assembly. These AC Delco Fuel Pumps seem to have an average life span of 100k miles, and mine very well could be at its end. After Replacing the pump, I noticed an immediate difference in power and throttle response, so that was nice. However the codes all remained for a few days. That was last week, and I havent had any issues or codes in the past week. Hopefully, the computer had to adjust to the new pump and my problems are solved. Ill keep this updated, but it looks like $175+shipping from Rock Auto and some sweat solved the issue. |
Did it keep working? Mines doing it again seems to come and go. When the check engine light comes on it shows p069e and it seems to run fine but when I erase the codes it starts to run rough and either dies or revs up while I’m parked and it smells like raw fuel like as if it were burning rich. p0446 And p069e were present as possible codes if the check engine light didn’t come on. Otherwise like I said before p069e is the only code shown when the lights on. No problems while driving only if I erase the code or the lights off it will have a hiccup and turn back on
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Daniel, thanks for asking again. I solved the problem. It was NOT entirely the fuel pump. It may have helped to change it, but there is actually a fuel pressure sensor hidden on the H3 Alpha. I'm not sure about other 2009s, but there is a fuel pressure sensor that the computer believes to be on the fuel rail. It is not on the fuel rail. On the 2009 h3 alpha, it is located between the cat converter and the transmission. if you are looking at the transmission from the front(engine side) it would be located about 3o'clock.
I found this by chasing the fuel lines. The lines come out of the pump(4 lines) and only 2 are easy to follow. The injection lines turn on the frame and go up the transmission, up into the engine bay where they are practically out of sight before connecting to the fuel rail. The pressure sensor is located on this line, youll have to chase it where it turns and follows the trans. If your code is reading "Fuel rail pressure sensor A" like mine, it means it is not giving the proper reading, or a reading at all, and the hummer sputters a little because it is not sure what mixture to pump to the injectors. Eventually, it enters "limp" mode to keep it from stalling. These leads to foul smelling exhaust, poor gas mileage, and poor throttle response. I took the truck to a mechanic who hooked his Tech 2 scanner to the OBD, and it showed the reading from the sensor as "0" for fuel pressure. Replace the faulty sensor by removing the little heat shield that "protects" the sensor from the exhaust heat. Then you'll need to grab a crows foot that fits over the sensor to attach to a ratchet. A regular open end wrench will not work because you cannot turn the wrench far enough to break the sensor lose. You'll need to give it one spin or so to be able to remove the plastic lock on the connector so you can disconnect the connector before totally removing the sensor. Then put the new one on, I found mine on RockAuto for 17 bucks. Now she runs beautifully. |
Oh, and for those of you with P069E codes for the fuel pump, find your modular control located on the body behind the fuel tank. the connector are probably covered in corrosion like mine were. just clean them up and reconnect them. That easily fixed my code.
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Originally Posted by Trog
(Post 367489)
Daniel, thanks for asking again. I solved the problem. It was NOT entirely the fuel pump. It may have helped to change it, but there is actually a fuel pressure sensor hidden on the H3 Alpha. I'm not sure about other 2009s, but there is a fuel pressure sensor that the computer believes to be on the fuel rail. It is not on the fuel rail. On the 2009 h3 alpha, it is located between the cat converter and the transmission. if you are looking at the transmission from the front(engine side) it would be located about 3o'clock.
I found this by chasing the fuel lines. The lines come out of the pump(4 lines) and only 2 are easy to follow. The injection lines turn on the frame and go up the transmission, up into the engine bay where they are practically out of sight before connecting to the fuel rail. The pressure sensor is located on this line, youll have to chase it where it turns and follows the trans. If your code is reading "Fuel rail pressure sensor A" like mine, it means it is not giving the proper reading, or a reading at all, and the hummer sputters a little because it is not sure what mixture to pump to the injectors. Eventually, it enters "limp" mode to keep it from stalling. These leads to foul smelling exhaust, poor gas mileage, and poor throttle response. I took the truck to a mechanic who hooked his Tech 2 scanner to the OBD, and it showed the reading from the sensor as "0" for fuel pressure. Replace the faulty sensor by removing the little heat shield that "protects" the sensor from the exhaust heat. Then you'll need to grab a crows foot that fits over the sensor to attach to a ratchet. A regular open end wrench will not work because you cannot turn the wrench far enough to break the sensor lose. You'll need to give it one spin or so to be able to remove the plastic lock on the connector so you can disconnect the connector before totally removing the sensor. Then put the new one on, I found mine on RockAuto for 17 bucks. Now she runs beautifully. |
Originally Posted by daniiel777
(Post 367483)
Did it keep working? Mines doing it again seems to come and go. When the check engine light comes on it shows p069e and it seems to run fine but when I erase the codes it starts to run rough and either dies or revs up while I’m parked and it smells like raw fuel like as if it were burning rich. p0446 And p069e were present as possible codes if the check engine light didn’t come on. Otherwise like I said before p069e is the only code shown when the lights on. No problems while driving only if I erase the code or the lights off it will have a hiccup and turn back on
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