Hey yall,

With weeks of tinkering on this trying everything I can i cannot understand why my truck will crank, run fine for 10 seconds then start making a sucking sound from the throttle body then die.

Let me back up. The truck is a one owner that hasn't run since like 2011 ish. I have to date repainted the frame, cleaned fuel tank, re o ring fuel pressure sender, new fuel pump, new fuel lines, checked firing order cleaned and regapped plugs.... etc.... I have everything for a full tune up with new parts but it runs too good at first to justify replacing all this until it runs on its own for a length of time.

I have not been able to successfully check fuel pressure at the rail due to 2 faulty gauges. Will work on that tomorrow​​​​. Just at my witts end. It does have a couple of small vacuum lines broke but nothing that should shut the engine down. I'm more familiar with a 12 valve rather than the 5.2.

Have video but trouble uploading cause it's a mp4 file from my device.

Thanks
Dusty

 

Will it stay running if you give it a bit of gas?

 

It does rev up when I jack the throttle about a 1/4 inch fast. Other than that it runs fine starts to make a sucking sound then sputters and dies.

No codes just the 55 code

 

if it will stay running if you give it some gas like HeyYou is suggesting it could be a dirty or sticking idle air control motor.

 

Cleaned it. It had some build up on it for sure. Left it out plugged and cycled the key and it moves so it "should" be working

 

Reset the pcm. Just disconnect the battery, turn on the headlights for a couple seconds, turn the headlights off, hook battery back up. Turn ignition to 'on', not start, do not touch anything, count to ten, THEN start the truck. Use the gas pedal to keep it idling for a bit if you have to. See if it will then idle on its own.

 

Okay I've gotten a day off to start back...

Got a good gauge and I am not getting fuel pressure to the rail. I'm getting up to 85 lbs straight off the pump and it slowly bleeds down.

Pulled the rail and all injectors. All injectors have been spraying clean fuel because the centers of them look brand new where is the outside is not so clean. So I'm ordering new orings. Rails are spot less.

Tested the rail with the old fuel line could keep my finger iver the line to keep it sealed off. Then i rigged a gauge up. But I had to do it backwards to work. So I pressured up on the return section and put the gauge on the pressure side. I blew the oring on the regulator at 60 psi.

My thoughts is the the pressure regulator is staying open and not allowing enough pressure to build up in the rail and its not showing up on the pressure test port.

So I'm gonna order a new regulator new oring kit for the injectors and new throttle body gasket.

 

Okay...... well I did everything I said I was gonna do in the last post. Bolted the fuel rail up installed the gauge and bam pressure..!!!!!

​​​​​Turned the key on and fired up and never tried to die. So I think my assumption with the fuel pressure regulator was the culprit.

Thanks for all the input guys. I'm sure I'll be back again with more questions.