An expert who has achieved level 3 by getting 1000 points
An expert that got 20 achievements.
An expert that got 10 achievements.
An expert that got 5 achievements.
Cars & Trucks Master
Re: Once you turn the key on it runs for one second &...
Only a guess as you don't state model or make. If you are testing fuel pressure at the throttle body you have a TBI system.
The ECM controls the fuel pump by allowing a short run time to prime and then requires oil pressure to keep the pump running.
If you are testing with out the motor running you are only getting the prime signal.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Ran a hot wire to what fuel pump or the control module ? Which of these is yours ?
Figure 9: Fuel Controls - Fuel Pump Controls (LY6)
Figure 10: Fuel Pump Flow Control Module (Except LY6) Does yours have fuel pump flow control module under the vehicle Fuel Pump Flow Control Module (except LY6)
Mounted to the left side of the frame assembly below the driver seat ?
Fuel Pump Flow Control Module (FPCM) - LMF
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a 25 KHZ PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal. Maximum current supplied to the fuel pump is 15 amps. A liquid fuel pressure sensor provides fuel pressure feedback to the FPCM.
Electronic Returnless Fuel System (ERFS) - LMF
The electronic returnless fuel system is a microprocessor controlled fuel delivery system which transports fuel from the tank to the fuel rails. It functions as an electronic replacement for a traditional, mechanical fuel pressure regulator. A pressure vent valve within the fuel tank provides an added measure of fuel pump flow control module (FPCM). Desired fuel pressure is commanded by the engine control module (ECM), and transmitted to the FPCM via a GMLAN serial data message. A liquid fuel pressure sensor provides the feedback the FPCM requires for Closed Loop fuel pressure control.
If your vehicle has this system check it for DTC'S - diagnostic trouble codes . Will take guess work out of it .
DTC P0191: Fuel Rail Pressure (FRP) Sensor Performance
DTC P0192: Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage
DTC P0193: Fuel Rail Pressure (FRP) Sensor Circuit High Voltage
DTC P0230: Fuel Pump Relay Control Circuit
DTC P0231: Fuel Pump Control Circuit Low Voltage
DTC P0232: Fuel Pump Control Circuit High Voltage
DTC P023F: Fuel Pump Control Circuit
The engine control module (ECM) supplies voltage to the fuel pump flow control module (FPCM) when the ECM detects that the ignition is on. The voltage from the ECM to the FPCM remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the FPCM supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.
DTC P025A: Fuel Pump Control Module Enable Circuit . Ford Electronic Returnless Fuel System Diagnosis Part 1 this for ford but the GM system works the same . You'll need a wiring diagram so you know what wires are what . Free wiring diagrams http://www.bbbind.com/free_tsb.html
What you are telling me is the engine is firing the plugs but not getting fuel. When you changed the fuel pump and filter, did you check the fuel pressure at the rail ? Are the injectors getting power and ground pulse ??
Before starting the engine, the fuel pump should only run for a few seconds when the key is first turned, to pressurize the fuel system. Even though the pump appears to be running, you may either have not enough or too much pressure for the engine to keep running (fuel pump or pressure regulator). I think it may just be a coincidence the engine quit while turning a corner, but the gas in your tank may have been so low it sloshed away from what is likely a very old pump, starving it and causing it to failure.
There is a fuel pump prime cycle (2 or 3 seconds)when you turn the key to on and once you start the engine the fuel pump power comes though the oil pressure switch.No oil pressure,no power to the pump.maybe your oil pressure switch has become weak?I would use a scan tool and command the fuel pump on when it does shut off,just to make sure the pump can run,as it could be a bad pump too.Also when it does quit,if you turn the key off for 10 seconds, you should get a prime cycle by turning the key to on.Have someone listen at the gas tank for a fuel pump noise,which will be only 2 or 3 seconds,but will do as a pump running check.Next would be to check for power at the back at or near the fuel pump,power and no pump.replace pump.No power to pump,follow power back to the front through oil pressure switch and fuel pump relay etc.You can always add your own power to the pump from a power source the switches off with the key if needed bypassing the existing wiring and oil pressure switch.
most newer cars it is located inside the fuel tank generaly when a fuel pump goes out its just done no more running occasionally, you will get a fuel pump with a short in its wiring and it will intermitantly not run such as i hit a bump it quit and later on it started and ran until the car was jostled again and once again quit this on is rare, but a possibility to check your fuel pump with no tools, open your fuel cap and listen carfully while someone turns the key to the on position when the key hits the on position you should hear a buzzing for about 3 seconds, if you hear this the fuel pump is working if you dont you may have a dead fuel pump good luck
You should be able to hear the fuel pump running in the tank for a few seconds when you first turn the key to the "run" position. If you can hear it, and the fuel filter is not plugged, then it'll be the MAF. Mass air flow sensor.
This could be many problems. But here is one to try. Turn your key on and make sure your fuel pump runs for 3 seconds. It will hum then quit. If you do not hear the pump running with the key turned on, replace fuel pump relay. This may solve your problem.
check electric fuel pump operation ( located in the fuel tank ). Occasionally a fuel pump will burn out when running out of fuel, due to the fact the pump runs DRY for about 30 seconds till the fuel stops flowing out of the injectors, the engine quits, simultainously losing oil pressure which FINALLY shuts off the fuel pump. Sometimes TOO LATE. Hope this helps