The truck is not hard to start and runs fine I'm just trying to test all options before replacing things. The cool thing is that you don't have to crack anything open to find out if anything is leaking inside, you can do a simple fuel pressure leak down test and based on the results of this test, you'll know if something is wrong with the ‘spider’ fuel injector assembly (of either type). Refer to fuel system description (fuel system description) Command the fuel pressure control to 160 mpa (23,206 psi) with a scan tool Read on to learn how to check for leaking fuel injectors to ensure your engine runs optimally and prevent fire outbreaks from external injector leaks and vacuum leaks.
If its a clogged or dirty fuel injector the problem will be there all the time while driving or start up ect Sounds like you have a bad fuel pump regulator if you dont have a regulator it might be the fuel pump that is going out It also sounds like a intake manifold gasket might be leaking Have you done a full tune up already I'll start with that first This allows the truck to crank over without injecting fuel to start
This fuel will spray out the glowplug hole All this test will do is show you which injectors may be sticking You may see the glowplug saturated when you remove it. Check the fuel pressure regulator While the truck is off pull the vacuum line off and see if gas comes out of the vacuum line If gas comes out replace the fuel pressure regulator
This is a common problem on almost all newer gm vehicles 96+ The spider injectors are in the older 96+ 4.3, 5.0, 5.7l motors not the 99+ 4.8, 5.3, 6.0 (a) too much air not enough fuel = injectors (b) too much air not enough fuel = exhaust/intake leak (c) intake manifold crack or vacuum leak if you find no cracks or leaks i'd run a can of royal purple max clean through the fuel system then watch what your fuel trims do If it stabilizes then it could be a clogged or faulty injector. Main points fuel injectors play a crucial role in delivering the precise amount of fuel into the combustion chambers of your gmc sierra Insert the fuel injector puller into the injector and attach it to the slide hammer.
If fpr is good, injector/s could be leaking or stuck open But it will cause a rich condition on the exhaust as detected by o2 sensor Fuel pump built in check valve is stuck open causing loss of fuel pressure during priming Starts but on 2nd or 3rd try. My fuel filter was dry However, i noticed that fuel appeared to be leaking from a fuel injector behind my fuel filter (unk what # fuel injector)
I want to replace fuel injector myself, but i have never done this before. I suppose you could fashion a test port that plugs into the fuel line at the fuel rail, so you disconnect the fuel rail, and plug this test port into the fuel line going to the fuel tank, and check the pressure turning the key on, to verify that the fuel pump is or is not getting up to around 60 psi, where it should be. Diesel in the crankcase can only come from 3 places 1) injectors 2) cp3 seal 3) return lines under the valve covers the high pressure rails on either side are not a source for fuel in the crankcase and leaks from those should be visible If you replaced the pump, was that a new cp3 or reman If new, you might want to look at the other two possibilities, if reman, you may want to check the cp3.
If equipped, replace the engine insulator if it has absorbed fuel or emits a fuel odor. Experiencing rough starts, fuel smells, poor mileage Learn how leaking fuel injectors can destroy your engine Risks, dangers—and what you can do to avoid it. The active fuel injector tester and sidi adaptor connects to the engine control module harness connectors to test the high pressure fuel pump performance, fuel injector wiring, and fuel injector operation. Leaking fuel injectors can cause engine damage
Symptoms are rough idle, hard start when engine is hot, poor emissions, fuel odors, oil thinning, hydrolock.
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