On Start Up Engine Continues To Try To Start-SOLVED

[tom3]

Try cycling the ignition off and back on 3 or 4 times. Wait 4 or 5 seconds between cycles. I'm suspecting a failing fuel pump. Giving it a couple primes might make it start right up if so. Maybe.....

 

[OR VietVet]

Yes, it does not grind like a person starting a car already started, it's like a dry crank with no fuel and then when it starts to catch fine it keeps trying to start?

Ok, this is a totally different scenario. Better details. Great.

Sounds to me like the sounds are normal for an engine that you are spinning/cranking with the starter but is having problems firing off and running. Sound about right? If so, that is a totally different set of inspections. I will wait, and other members too, to see what you say back about my questions.

So many times people ask for help about a no start condition but what they share is not matching up. You can have a no start by turn key, engine spins but will not start. That is a whole different set of inspections than if someone says will not start and what it is doing is not even spinning over, "Like it has a dead battery". I am not saying it has a dead battery but a no crank/spin condition is a different set of checks.

Then you get in to internal damage that causes weird cranks and no start and and and and.

I also agree with @tom3, about possible fuel pump problems. I was leaning there by the time we got this far but still wanted some answers to those questions.

But whatever, good luck and let us know.

 

[jabberjaw401]

Post to YouTube or the like and post the link in your message.

Post to YouTube or the like and post the link in your message.

 

[OR VietVet]

Sure does sound like the fuel system lost it's prime. Did you try what @tom3 said after it sits for a long enough time? If what he suggests allows it to start quicker, then it can be the fuel pump but also could be a leaking injector. I am assuming of course, you do not smell gas.

 

[wsteele]

I have a 2007 Yukon 5.3L FF (LMG). If it were my truck, I would be thinking my fuel pump is about to go south.

If you can get ahold of a fuel pressure gauge (you may be able to borrow one or rent one cheap at your FLAPS, a quality new one costs like $30 so don't pay a lot for a rental), drain off the residual pressure in the line at the Schader valve with the blade of a screwdriver (on the passenger side fuel rail) and hook it up. Turn the key on once (on not start) and leave it on, go check the pressure. It should read between 50-60 psi. If it doesn't, you likely have a failing fuel pump.

 

[Larryjb]

+1 for the fuel pressure gauge, especially when starting.

I notice that it's a hard start the first time, but after that it starts much easier. This suggests to me fuel pressure is leaking down over time.

I have the older style with the fuel pressure regulator. You're doesn't use one, so I got curious. The video below actually has some good diagnostic steps:

(Although this video is for the older style, some good diagnostic steps are shown.)

 

[wsteele]

+1 for the fuel pressure gauge, especially when starting.

I notice that it's a hard start the first time, but after that it starts much easier. This suggests to me fuel pressure is leaking down over time.

I have the older style with the fuel pressure regulator. You're doesn't use one, so I got curious. The video below actually has some good diagnostic steps:

(Although this video is for the older style, some good diagnostic steps are shown.)

Actually he does have a fuel pressure regulator, unfortunately it is located in the fuel pump assembly, not up in the engine compartment like yours. I believe the last few years of NBS moved the FPR into the pump assembly. The 2007 kept that setup and only in 2008 did they get a whole new pressure regulation strategy with the FPCM and pressure sensor. He can actually change the regulator in that assembly but it is so much work dropping the tank to replace the pump, I think just replacing the whole shebang makes more sense at that point.

 

[OR VietVet]

I think the statement, "continues to try to start" may come from hearing the starter drive still spinning after he lets the key go. If it isn't that, I have no idea what he is trying to get across to us.

If originally he said, " Have to try cranking engine 3-4 times before fires off. Then runs fine and restarts easily if crank right after shut off", this would have been short diagnosis but that phrase thru me.

I have to try and remember, just like my customers in my shops, the customer is telling us what they seem to be experiencing but most of them have no mechanical background and will say things that don't mean anything.

He is new to forum so may love his rig but hopefully gets used to reading here and starts to adapt. The more you know about your rig, the better.

 

[wsteele]

I think the statement, "continues to try to start" may come from hearing the starter drive still spinning after he lets the key go. If it isn't that, I have no idea what he is trying to get across to us.

If originally he said, " Have to try cranking engine 3-4 times before fires off. Then runs fine and restarts easily if crank right after shut off", this would have been short diagnosis but that phrase thru me.

I have to try and remember, just like my customers in my shops, the customer is telling us what they seem to be experiencing but most of them have no mechanical background and will say things that don't mean anything.

He is new to forum so may love his rig but hopefully gets used to reading here and starts to adapt. The more you know about your rig, the better.

I think it likely is the fuel pump, but as you pointed out early on, it can be something else that causes the bleed down of fuel pressure in the rail after shutdown.

A gauge test will confirm where he is at pressure wise. That test is the first step in the diagnostic process in the shop manual for the '07.

 

[jabberjaw401]

Sure does sound like the fuel system lost it's prime. Did you try what @tom3 said after it sits for a long enough time? If what he suggests allows it to start quicker, then it can be the fuel pump but also could be a leaking injector. I am assuming of course, you do not smell gas.

Let me try here in a bit sorry guys I work nights and back to work tonight so my response times may seem weird, my son is getting ready to go to the Navy and we are still recovering from Florida lol I have a disabled 15 year old too lol good boy though