Engine cranks but won't start no fuel pressure pump has no power going to it, running fine till I parked it then when tried to start to leave would crank but no start. I checked the fuel pump and found to power supply to the pump at the tank supply.
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Re: No current to the fuel pump at the fuel tank
Have somebody cycle the key on and off and see if you have power not cranking the engine just from the off to on or run position. If no power, check your fuse for the f/p and the coresponding relay. bet way to check fuses is with a test light. Most times a power window, a/c or heater relay will be the same and you can switch it out to see if it solves the problem. mike
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the fuel pump will run for 2 secondes with key on to prime system. then when you crank engine it should run all the time. you check fuse and if current go to fuel pump at tank connector. if there is current then the fuel pump must be defect.
You may be right on your hunch. The fuel pump gets power from the pump relay for 3 seconds when you turn the key on, then no power until the engine starts. If the fuel pressure is low it could take several trys to get the pressure up to normal and the engine start. A mechanic would check the pump relay and the fuel pressure with a gauge before and after cranking the engine.
My first question would be is the injector spraying when you crank it ? The way its supposed to work, the fuel line to the tank should have about 10psi of pressure before you crank the engine. When you turn the key on the pump gets power for 3 seconds to boost the pressure. The pump stops working until the engine has oil pressure which takes a few seconds. If the base fuel pressure leaks back to the tank, or the pump relay is not powering the pump, you won't have any fuel pressure or spray until you get oil pressure.
To clarify, the engine cranks and starts. If it cranks but won't start until 4 or 5 tries, I would check the fuel pressure before and after the first attempt. The check valve in the pump may be faulty and allowing the fuel to flow back to the tank when it is not running. The pump only gets power for the first 3 seconds during crank time until the engine starts.
How many miles on the car? Have you checked the fuel pressure when it doesn't want to start? Do that first and then move on from there. To quickly test fuel pressure with no special equip get a can of starting fluid from the auto parts store, when it fails to start spray the fluid into the air intake of the engine well it is cranking, if it fires up then the fuel pump is likely not running on for some reason. This can be electrical in nature or just a failed electric fuel pump
Check for spark and fuel. When you turn the key on you should hear the fuel pump in the tank for a few seconds till the pressure builds up. When you crank the engine there should be spark at the plugs.
There is a check valve in the tank, part of the sending unit. you can't buy it by itself. Instead of cranking on the starter to get it started. just turn the key on and off 3 or 4 times. it energizes the fuel pump everytime you do it. this should get your vehicle started.
You need 3 things.
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems. One test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem. Run the full fuel pressure test and post back pressures. Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Also you mentioned that you replaced the fuel pump, it's common for the $15.00 wire harness from the fuel pump to the frame will break and there is a bad connection till the wires heat up. You can try this trick, turn your ignition on for 30 seconds "engine not running" and then turn it off for for 5 seconds and then try to start. This will energize the fuel line if the fuel line check valve is bad which is a part of the fuel pump and will heat up the wire harness which will make a better connection and see if the engine starts easier. Regardless, inspect the wire harness for corrosion and the ground is good. Good luck and keep me posted.