I was putting my truck back together from a head gasket job, I started the truck up, it ran fine. I detected a coolant leak at a hose. I shut the engine off to tighten the hose clamp. I start it back up again, and now I get P0192 Low Fuel Rail Sensor Voltage code. Truck's missing out and in limp mode (not revving over 2000 rpm.) The FPRV seems to be letting the fuel out of the rail. I replaced the FPR while I had the truck apart with a new one from merchant auto. Could a fault FPR be causing the FPRV to pop off, or do I have a faulty FPRV spring?
P0192 Low Fuel Rail Pressure
- Thread starter chandler583
- Start date
No, sensor is plugged in. I traced the wire from the sensor to the ECU, everything seems to be good on it. I'm wondering what would cause the FPRV to pop off, as I think that is what is causing the low fuel rail pressure.
After a full day of trouble shooting, we think we have it nailed down to the fuel pressure sensor being faulty. I am ordered a new sensor, but I would also like to replace the fuel pressure relief valve as it was letting fuel out. I don't want the weakened spring to be an issue later. Does anyone have any idea where to get the stock relief valve? I see a lot of plugs to remove it all together, but I'm not sure I want to bypass a system designed to protect my fuel system.
Sorry to derail but what does a relief do and how do they go bad? Is this what a bottle test determines? What are symptoms of a bad valve? Sorry for the questions just trying to learn.
Sorry to derail but what does a relief do and how do they go bad? a fuel pressure relief valve (fprv) is installed by the factory to open up when the rail pressure gets above a certain psi. Like your water heater valve, it's not supposed to let fuel through. But, overtime, or in my case, the pressure sensor goes bad and allows the relief valve to release the fuel back to the tank, the spring in the relief valve gets weak and will open at lower than factory pressures.
Is this what a bottle test determines? Yes
What are symptoms of a bad valve? DTC codes will be thrown, loss of power in wot circumstances.
On your LB7, the relief valve is in the valley of the engine as opposed to the end of the drivers side rail in all other models.
Yeah, I'm thinking that I should just go with the race valve. It's a cheaper option, and I don't see people having real problems with it.
Is this what a bottle test determines? Yes
What are symptoms of a bad valve? DTC codes will be thrown, loss of power in wot circumstances.
On your LB7, the relief valve is in the valley of the engine as opposed to the end of the drivers side rail in all other models.
Yeah, I'm thinking that I should just go with the race valve. It's a cheaper option, and I don't see people having real problems with it.
http://www.kennedydiesel.com/docs/Duramax LBZ and LMM P0087 Low Fuel Pressure code.htm
Search P0087 or Google (Duramax P0087) and you will bring up all the diesel sites. Lots to raed.
GM Part #97358556 New OEM $222.93
http://parts.nalleygmc.com/showAsse...ukey_driveline=0&ukey_trimlevel=0&modelYear=0
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Ok, so I replaced the fuel pressure sensor and it corrected that issue. Now, after about 10 minutes of running I've got a misfire on cylinder #6 and a MIL (P1238). Anybody with experience know where to check now? From what I've read, it's a connection issue with the injector, the FICM, and and ECM. As far as I know, this truck hasn't been "ice picked" should I start there?
Update: After moving injectors around to isolate the problem unsuccessfully, we found the problem to be a worn wire going into the FICM.