Hello, I am a Master Technician and I'd like to help you with your problem. Please continue our conversation and refrain from rating until you are satisfied. I will work with you as long as it takes to get this figured out. I'd like to do some Q&A first if that's ok so I can get a better understanding of what is goind on.This initially sounds like your engine may be flooded which can happen in several different ways. I had the exact same problem with my Suburban. To clarify, when it starts up without holding the throttle open, is this after the truck has set for a period of time(i.e. overnight)?
How is your coolant level? Is the reservoir or radiator low?
My coolant level is fine, in fact coolant was added less than 1 month
I was thinking that the cause might be dirty fuel injectors, so yesterday I added a gas additive that is suppose to clean them but not enough start ups have occured to determine if that has helped!
The reason I ask is because two things can commonly flood an engine, either coolant or fuel. When it's flooded, you have coolant or fuel sitting in the intake or cylinders which has to be cleared out before it will start. It clears out by cranking the engine with the throttle held wide open. Typically, if you have coolant flooding the motor then it will be hard to start no matter how long it sits because the coolant does not evaporate. If you have fuel flooding your motor then if it sits long enough(i.e. overnight) the fuel can vaporize/evaporate enough that it will start up ok.If the motor is flooding from gas, it's usually because of a leaking injector. When you shut the truck off, fuel pressure is still in the lines and the injector will sit there and drip fuel into the motor. The best way to check for this is by hooking up a fuel pressure gauge and watching the pressure after you shut the truck off. It should hold pressure. If pressure starts dropping off almost immediately then you have an injector leaking. The pressure could also drop off due to faulty pressure regulator or fuel pump but this would cause the fuel to go back to the tank leaving the lines empty and causing a long crank but it will start rather quickly without holding the throttle open. It just takes a few seconds for pressure to fill the lines again before it will start. If you have to hold the throttle and crank it for a bit then that sounds like leaking injectors. Are you comfortable hooking up a gauge to check fuel pressure? Your local parts stoor should have a tool loan program where you could get a fuel pressure gauge.
So I know which setup we're dealing with, what motor is in your truck?
Is this a difficult task-I am not comfortable with most car repairs. Routine maintenance is my forte! Can this be done at an auto repair shop, reasonably?
It is a 5200 V8. Does that help?
Yes, the fitting where you hook up the gauge is easily accessible and the test pretty easy to perform. Now changing the injectors is bit more involved. A shop should not charge more than an hours labor to test the system and check fuel pressure.
What would I request when callin a repair shop for a test?
Another test you could do without tools to narrow down the possibilities is to relieve the fuel pressure after you shut it off. If there is no pressure in the fuel lines then the injector should not drip. So if after shutting the truck off, you relieve the fuel pressure and the problem goes away then we can safely assume you have a leaking injector. This test can be messy as yo
How is this done?
This test can be messy since you will be letting fuel out of the fuel rail by pressing the valve on the line. You will initially want to shield yourself with a rag because the pressure will be high at first and the fuel will spray. After you intially let the pressure off it will then just dribble out of the fitting. You would need to continue to relieve the pressure until the motor cools because the heat from the engine will cause the gas to expand and continue to build residual pressure. We keep pressing the valve to prevent pressure from building up by the heat.
If you relieve the pressure and it starts right up without holding the throttle then we will have determined for sure that we are dealing with a leaking injector. When you go to start it though, you will want to cycle the key a few times to prime the fuel lines and build your pressure back up other wise you may have a long crank due to the lack of pressure in the lines. Each time you turn the key to on(not start) the pump runs for a few seconds to build pressure.
I think the easier test for me and my experience is to have a fuel pressure test done at an auto repair shop! so, if you do not have any more suggestions to assist with my problem, I will refrain from rating your answer until I get my truck checked out. If this resolves the problem you will be given an excellant rating!
When you look at your intake manifold, you need to look for the fuel lines which go to the fuel rail which feeds the fuel injectors. On this line, you will have a valve whcih is similiar to the valve stem on your tires. It will be slightly larger and metal on a metal line. You may or may not have a plastic cap on it that will need to be removed. To relieve the pressure you just press the valves pintal with a screw drivers etc (just like relieving air form a tire). Agian fuel will spray at first so shield yourself from the gas so it doesn't get in your eyes etc.
This is not a test that I am comfortable performing!
No problem, I am at your disposal for as long as needed. I defintiely agree that having someone check the pressure for you would be more accurate and less messy. They should also no how to interpret the readings and isolate the problem to either the pressure regulator or injectors.
You are welcome. Let me know what they find. Thanks.
It has taken me this long to get an appointment for my truck and have a fuel pressure test done. Thankfully following the fuel pressure test the problem was found and another 1/2 hour my car was fixed. This after 3 trips to other repair shops who didn't know what was wrong! So, even though you were not completelycorrect in your answer to the problem with my truck, because of your suggestion to have a fuel pressure test done the problem was found and resolved. So I am rating you OK. The real problem which was then replaced was the fuel pressure regulator. Thank you