Fuel problem? 1990 F 150 6 cylinder twin tanks. Will not start. If Ispray gas into the intake it will run. Once I stop spraying Ihave to keep pumping the gas just to keep it chugging. Once Istop pumping the pedal it stops. It was running fine when Iparked it about a month ago with both tanks full. I replaced thefuel filter and checked the fuel pressure at the rail(50psi). Whats next?

did you replace low pressure pump in tank, There is actually a low pressure pump in each tank and a high pressure pump inside the drivers side frame rail about right under where the driver sits.

Gas, air, compression, and spark is all the cylinders need for the engine to run. No start is usually gas or spark related. Here's the fuel check on fuel injected cars. Turning the key to on will start the pump for 2 or 3 seconds to pressurize the system. When the engine is cranking over the computer turns on the fuel pump relay again, so the pump will be on. And stays on after engine is running to keep high pressure against the fuel injectors. The computer times the injector pulse to spray gas into the intake or into the cylinder at the right time.
So if you have a no start, to check for gas, listen for the pump- a distinctive hum or buzz from the tank, check the fuel pump fuse, see if you can feel or hear the fuel pump relay click when someone turns the key to on. (Did you remember to check if the tank has gas?). Finally, you would have to check for power on the fuel pump wire at the tank connector, while someone holds the key in start. If you have power there, it's likely you need a new fuel pump. If the pump is working, well and good, but keep in the back of your mind that a weak pump that puts out low pressure can cause hard starting problems and poor running. At any rate, if you have gas up to the fuel rail, the only other thing between there and the cylinders is the injectors. Are they working? A quick check would be to remove a spark plug or two after cranking the engine over a few seconds. If they are wet with gas, the injectors are injecting. Hope I've helped you out some. I know some people who say to spray some starting fluid into the air intake to check if you have a gas problem with starting- I've done it myself. But I've learned it's better to use carburetor cleaner spray instead, it burns cleaner and something about the potentially harmful effects of starting fluid, well. good luck.

it sounds like the fuel pump needs replacing.by spraying either and it starts tells me there is no fuel getting to the cylinders.

Best way to fix it when you run out of gas is this. Because you ran out of gas, means your fuel filter is out. When you run out of gas, you end of getting like a air blockage in the line. Now, professional way is to take fuel filter off and fill with gas and put back on, BUT i will tell you a back yard mechanic secret way. Is get a can of starting fluid ( you can get at any auto parts store) and while someone is in side the Pickup, have them ready to turn the key. You are outside with the hood up, and you will be spraying a little bit of the starting fluid in the air intake of directly in carb area ( if carborated) but just spray into air intake. Have them crank the engine, at same time you will spray starter fluid in air intake, just a couple of quick sprays. You will notice it will start and maybe die again. That is normal, you might have to do this a couple times to get things flowing. HOWEVER, what normally happens when you run out of gas, the fuel filter picks up all that junk that has been gathered in the bottom of fuel tank and it has clogged your filter. FOR SURE, if you replace your fuel filter, it will solve this problem. Thank You, and I hoped this helped you.

Get a bottle of STP fuel system treatment (maybe two) and run with next tank of fuel. That'll clear it out. You might also want to change fuel filter after that tankful.

well you narrowed it down to a fuel problem. not sure about your model, but most cars have a fuel pressure regulator on the fuel rail to reduce un needed pressures. that could possibly be bad. its cylinder in shape and has a vacuum hose connected to it. check the hose and that unit.

CHECK EXHUET SYSTEM CATAICLIC CONVERTER COULD BE CLOGGED

Have a look at your fuel sysytem which comprises of injector and fuel pump and the fuel hoses.

Good luck.

Check/Change Fuel Filter(s), PVC Valve & Emission Hoses
and/or
Gas that sits too long won't fire easily that's why we have to add winterize to our lawn mowers!
Try filling the tank with some high grade fuel cleaner additive. This stuff is like rocket fuel (about $10).
Also add a can of dry gas as you may have a lot of water and water vapor in your system!
Get a couple more cans of starter fluid too. (I always needed at least two to get my diesel running for summer)
Keep spraying and starting (It always took me at least a full can sometimes 2)
When it starts keep the gas pedal down and rev high for a good 5-10 minutes then see if it will idle.
If it still stumbles and falls consider adding another can of fuel system cleaner and/or dry gas.
Don't drain the tank as this usually just makes it worse by letting the bottom sludge stir up.
Never let your gas tank get too low as this will foul up your fuel system and always add fuel cleaner after every oil change (a must for fuel injection and cat. converter care)

Good Luck!
jack
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