I had to change the fuel pump in the tank. It would only idle then stall the pump was rattling and inconsistent. I replaced the complete sending unit And rewired in the new replacement plug. The truck ran fine for 3 days. Wire pump direct to battery pump works fine. Checked for power on grey wire from truck have power. Checked for ground on the black wire seemed a little weak. The fuel guage works fine. I am guessing the pump uses a ground source to start. Is this relay the unit on the frame above the tank at the front of the box on the left side. I run a direct power from the fuse panel using the ground from the fuel pump truck wire would not start. Ran the ground wire to frame pump works fine. I have been running the truck wired this way for 2 weeks works fine but I would rather correct the problem and wire it back to original. Thanks for the help.
If I understand right, I would say the normal ground for the pump is bad.
"I am guessing the pump uses a ground source to start." well, just the normal ground like for any motor, you have the power wire (gray) to the pump, then the ground wire for pump, does it branch off near the tank and find a ground? Or does it go into the tank connector and then routed back somewhere through the wiring harness? Anyway, it has to go to ground somewhere. You have the wiring right it sounds,. just make a good ground source, or find the original ground and repair it.
SOURCE: 2000 S10 4.3L
Did you verify that the relay terminals have the appropriate signals to them?
ECM fuse B (20-amp) should provide power at all times to the orange wire of the fuel pump relay. The relay coil receives ground via the black wire, and relay coil gets power from the dark green/white wire. When the relay is closed, you should have battery power on the gray wire.
The relay trigger wire should have power from the dark green/white wire in terminal 1 of the Vehicle Control Module (VCM) connector for the first couple of seconds after they key is turned to run (to prime the system) and when the truck is running. Checking for all the appropriate signals at the relay is where I would start. That is after I checked for diagnostic codes.
Believe the fuel relay is the middle relay out of the three in the left rear of the glove box. Last thing is to hot wire the fuel pump if you can not get it scanned, see if the pump is bad unless your going to have a shop work on changing the fuel pump.
Good luck and hope this helps. keep me posted.
SOURCE: 97 gmc pickup, 5.7 eng, fuel pump not operating,
What you need to do is check you fuel pressure. Go to a local auto parts store and buy a fuel injection pressure tester. The pressure fitting is on the top of the motor its a 3/8 ish sized metal line and has a screw on fitting like a tire valve does. This line comes up from the back of the motor to the right of the distributor and goes down into the intake. Make sure to have a rag handy to catch the fuel seepage. After you connect the pressure tester turn the key on and off three times and read the gage you should have atleast 58 pounds of pressure. If you have 56 pounds it won't run because the fuel injectors are a poppit valve style and need atleast 58 pounds of pressure to operate.
SOURCE: my suburban will start runs rough but dies when
Have the fuel pump checked for fuel pressure. Sounds like you got residual pressure but not sufficient running pressure.
SOURCE: It runs for about 2-3 miles at 60 mph and then
First off, I appreciate your thorough description of what the symptoms are, ok lets go on. It sounds like your air/fuel ratio is off and is getting progressively worse. I don't think you will get this on the first guess. There are things you need to check out with the trucks systems to help narrow your search down. I don't know the trucks maintenance history but if you know that may help.
Look at the EGR valve, if it is stuck that would let an uncontrolled amount of exhaust gas back into the engine for reburn.
If the CAT is clogged the excessive back-pressure would cause the engine to run richer thus loosing gas mileage.
You really need a scan-tool to help. This type of device would allow you to look at live data and see if the component is operating within the specified range. Also a repair manual would help describe to you, the procedures to test suspected components. If you have anymore questions, let me know.
SOURCE: I have a 97 gmc sonoma and replaced the fuel pump
It really helps if you post which engine you have and the 8th VIN digit. I ASSUME its a V6??? You should have 12 volts for 2 seconds on the gray wire (at the pump) when you turn the key on, If not, check the ECM/BATT fuse #9 20 amps, in the dash fuse panel. IF you do have power, then the relay is working and that is ok, If it does have power to the gray wire, then shuts off after 2 seconds thats normal. NOW while its running the fuel pump gets power THROUGH the OIL PRESSURE SWITCH. So get it running with your test wire, then disconnect your test wire. If it stalls out, then the oil pressure switch is either bad or disconnected.
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