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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
Noisy pumps are going bad. It probally pumps but it can't make enough pressure and flow under pressure. Fuel pumps are checked with fuel pressure gauge for pressure and checked for flow rate to manufactures specifications.
It may BE losing fuel pressure, Robert. Check the fuel pressure and flow rate at the fuel rail. Filter, plugs, and cap have nothing to do with fuel pressure - your fuel pump and pressure regulator are the only things that can change fuel pressure very much.
Fuel trim lean, banks 1 & 2. That's a pretty strong indication that you should check the fuel pump pressure at the fuel rail, and check the fuel flow rate while you're there. There's a good chance that your fuel pump is just about ready to be replaced.
If you see good pressure & flow rate, run a couple of jugs (not at the same time) of carburetor & fuel injector cleaner through the gas tank. It's possible that all your injectors have just gotten so dirty that they can't give you a full-rich mixture.
You'd best do it fairly soon - the engine is running lean, and it can't tolerate that for any great long time without some damage.
The fuel pump relay is behind the cover on the firewall,turn the ignition on,and it will click,and you will find it,the fuel pressure regulator is on the fuel rail.On the intake.Rate please if this was helpful.
i'm assuming you disconnected the fuel line and placed the line in a container to catch the fuel when observing the flow.
it might sound strange but i think there might be a leak in the tank coming from the fuel pump assembly. it's possible a tube or hose is broken on the assembly and the pump is just pumping the gas back into the tank.
there's flow because there is no pressure building up with the line disconnectedand the gas flows. when connected, pressure builds and blows out the break in the tube or hose.
It seems the fuel flow rate not the the pressure is the problem here. If you have checked all your fuel filters (including the one in the tank) and found them clear. And there is no kinks or obstruction in the fuel lines, then you will need to have the flow rate of the pump tested. The pump may have to be replaced. Check you pump relay too. It shopuld cause the pump to run for one second and stop until the engine fires. It may not be re-starting the pump again and the engine is trying to get by eith gravity feed.
Check the fuel pressure, fuel pump (which is inside the fuel tank), fuel pressure solenoid (if fitted) and fuel pressure regulator (if fitted). Check and replace the fuel filter and check the injector flow rates in case you have clogged or faulty injectors.. I would lean towards a fuel supply issue here so look at the fuel filter and fuel pump first..
They might be refering to the MAP Sensor.
A manifold absolute pressure sensor (MAP) is one of the sensors used in an internal combustion engine's electronic control system. Engines that use a MAP sensor are typically fuel injected. The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine's electronic control unit (ECU). This is necessary to calculate air density and determine the engine's air mass flow rate, which in turn is used to calculate the appropriate fuel flow. (See stoichiometry.)
An engine control system that uses manifold absolute pressure to calculate air mass uses the speed-density method. Engine speed (RPM) and air temperature are also necessary to complete the speed-density calculation. Not all fuel-injected engines use a MAP sensor to infer mass air flow; some use a MAF (mass air flow) sensor. Several makes use the MAP sensor in OBD II applications to test the EGR valve for functionality. Most notably General Motors uses this approach.
How the MAP value is used
The manifold absolute pressure measurement is used to meter fuel. The amount of fuel required is directly related to the mass of air entering the engine. (See stoichiometric.) The mass of air is proportional to the air density, which is proportional to the absolute pressure and inversely proportional to the absolute temperature. (See ideal gas law.) Engine speed determines the frequency, or rate, at which air mass is leaving the intake manifold and entering the cylinders.
(Engine Mass Airflow Rate) ˜ RPM × (Air Density)
(Engine Mass Airflow Rate) ˜ RPM × MAP / (absolute temperature)
They could also be refering to the fuel pressure sensor. If so, then yes this also can cause the problem. You shoud have your fuel pressure checked for about $34.00. If you have a bad fuel pressure regulator you will need to change it out. If it remains undelt with then it could take out your fuel pump. Most fuel pumps are located and installed in the top of your fuel tank and are submerged into your tank. It needs the fuel to keep it cool, but if you continually keep your fuel under 1/4 of a tank you will drastically reduce the life of your fuel pump. Fuel pumps can be expensive to replace. I replaced my wifes in her 1997 Chevy Blazer and it cost me $350.00 (lifetime warrenty). If you keep your gas under a 1/4 of a tank most of the time and your pump is found to b bad then you need to opt for the LIFETIME replacement pump. You only want to have to pay for the pump once, believe me. Otherwise you really haven't provided enough of the symptoms to go on. Does it shut off when you are at speed, or stall when at a stop? If it stalls when you come to a stop you could have bad Oxygen sensor(s). If it's the oxygen sensor(s) then you should replace all of them.