No fuel to throotle body truck will not start. Only start if prime the throttle body then shut off

You'll have to do a fuel pressure test to see if the fuel rail is maintaining fuel pressure. If psi falls, it's either a leaking fuel injector, bad fuel pressure regulator or bad check valve in the fuel pump. Since you've replaced the pump, chances are it's one of the other two.

Must be your fuel pump has quit working. There should be fuel under pressure in the line to the throttle body, just by turning the key to on, not start. Not real high pressure like in multiport injected engines. Throttle body injection runs on about 20psi. If no pressure in your lines, find out why the pump is not working.

Could be many things throttle body tps fuel regulator temp sensor without codes an diagnostics could be anything no fuel in tank.


Hope this helps:-)

Not enough fuel to the throttle body. Check fuel pumps and lines.

This happened to me I had to spray Starting fluid everytime eventually. Starting fluid wouldn't work after awhile. Its the fuel pump. Even though it comes on and works its not producing enough fuel pressure to start the engine. It's probably giving about 12-13lbs of pressure but it needs atleast 14lbs. of pressure. And a word of advice to buy a ACDelco original fuel pump if you don't want to have to replace it again in 1-2 years, it's more expensive but will last.

The way to prime the fuel pump is to turn the key on.This will make the pump run for 2 seconds then turn off.Shut the key of for 10 seconds then turn it on again.You may have to do this a couple of times to get the fuel to the throttle body.Also when you turn the key to the start position the pump will run til you let go of the key.Hope this helps.Good luck.

This sounds like a fuel pump is starting to fail. The system is designed to keep, or at least prime rather quickly to allow for efficient starting. If the pump is begining to fail or, has a plugged fuel filter (which will kill a fuel pump), it may create this issue. One other item to check is the coolant temperature sensor. If it is reading warm when it is cold, this symptom will occur.

take the intake tube off the throttle body and spray your starting fluid in there. if it starts then dies, its your fuel pump. it could also be the pump relay, or inertia switch, aka emergency shut-off switch

i have the same problem on a 98 jimmy 4.3 4x4.
i replaced the fule pump and have good pressure.
new wiers & coil (good spark) no MIL & no codes.
will only start when primed. it will run & drive all day
with no problems.
but once it has been turned off (warm or cold) i will
have to prime it once again to start it.
i have another engine that was in it before it spun a bearing.
it ran fine so i know all parts are good.
i swaped the mass air flow and throttle body but i still have
to prime it everytime to start it. am i forgetting something?
should i swap out the intake with the injectors?
any help would be sweet. thanks.

Did you change the fuel presure regulator located in the throttle body?