Truck Won't Start

[Giant]

I have a 99 GMC Yukon that was in an accident a couple months ago. Its frame has been straightened, and body panels replaced. I've since gotten in and done the mechanicals. It ran yesterday just fine. now this morning I go to turn it on and it catches like it wants to run, runs for about a sec or two, then dies. I then try to start it again and it won't catch. If I let it sit for a few min, I get the same thing. It will start for a sec then die.

 

I want to say its a fuel related issue, but it has 1/4th of a tank and I haven't changed anything since yesterday. I don't get it.

 

Unfortunately I don't have anything to pull the codes with or I'd start there first.

 

Any help would be greatly appreciated.

 

Thanks

-Robert-

[asepgrad98]

maybe the security system or fuel pump

 

you need to find out the what the fuel psi is when this is happening

[asilverblazer]

Is the mass air flow sensor connected and working?

[Giant]

how can I check the fuel pressure without a pressure gauge? Also, any easy way to check if the fuel pump is running? Can you hear it if you crawl under the truck?

[Giant]

Is the mass air flow sensor connected and working?

 

It's connected. and it was working yesterday. Let me dig out my multimeter and see if I can check it.

 

It's almost like when you choke an engine and forget to shut the choke off. The first time it catches, then saturates and dies. After that it hardly catches until its pretty much flooded. If you leave it sit for a bit, it runs when the cylinders dry out a bit. But being fuel injected, how does the computer effectively choke the engine before it starts?

 

Thanks for the help so far.

[ZR Rider]

You should hear the fuel pump when you turn the key to ON pressurizing the sysytem

[Giant]

The fuel pump is running when I turn the key on.

The air is good as it was working yesterday and is just the intake hose + filter on the end.

The only thing left to double check is the spark (which since it fires and starts at first for a couple sec I can safely assume is ok)

 

The only thing I can think it to be is a bad sensor that is causing the computer to either lean out or saturate the fuel mixture and it keeps dying from that.

 

I'm going to see if Autozone has a fuel pressure tool and a code reader/clearer I can rent to try and diagnose this.

 

Thanks for the help thus far

[vortec22]

Could this be the security system shutting it off? I have heard of trucks having these symptoms and they needed the security re-learn done. I am not sure on this, but it sounds pretty similar.

[Giant]

lol... found the truck was just flooded. It ran fine this afternoon. Maybe the truck just doesn't like to start in the morning.

 

Either way. Thanks for the help.

 

-Robert-

[asilverblazer]

The question still remains how did it get flooded? I've heard on the fuel injected engines if it is flooded, to floor the accelerator, while cranking...

[Giant]

That is how I got it to start, my dad said to floor it for a sec, crank it with the pedal floored, then once it catches, let up.

 

the big kick is that the battery was disconnected all night. Yesterday and today it's run great.