2006 Silverado 5.3 floods when starting

I got a 2006 5.3 silverado that floods out when I try and start it. Its always the worst the first time I start it each day. I bought this truck with a bad frame, and switched everything over to a new frame. So I did have alot of stuff apart on this truck. I asked my mechanic and he thought that maybe an injector could be leaking fuel into the engine. But I took the fuel rail out and watched for leaks, but I didnt see anything. Also the fuel pressure is at the correct psi. What Could be causing this? Thanks

Does the fuel pressure hold when you turn off the ignition? What temp is the ECT reporting to the PCM (if you have a scan tool)?

//2000CAYukon

Check the vacuum hose for fuel in it.
Always check pressure on a cold start cranking and after it warms up?
What is your fuel pressure specs?
Does it have black smoke out tail pipe?
Any codes or check engine lights?
How are you figuring it is flooding?

Hey, I had a guage on the rail, I had 62 lbs. when I turn the key on, then it drops to 56 and holds there. I know it's flooding because you have to hold the throttle down a bit and when it finally starts it shakes around and smokes black. You talk about gas coming in the vacume line. Which line and how would that be possible ??

Hi, Check Dist. Rotor

Does the fuel pressure hold when you turn off the ignition? What temp is the ECT reporting to the PCM (if you have a scan tool)?

//2000CAYukon


I would guess he probably hit it right on the head, wouldn't be the first truck to think its a different temp than it actually is..

Hey, I had a guage on the rail, I had 62 lbs. when I turn the key on, then it drops to 56 and holds there. I know it's flooding because you have to hold the throttle down a bit and when it finally starts it shakes around and smokes black. You talk about gas coming in the vacume line. Which line and how would that be possible ??

The vacuum line on the fuel pressure regulator.
If fuel in the line regulator is bad.

As said check both of the tempt sensor readings in the VCM
Several things can make it act like it is flooding.

Run the full fuel pressure test.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 55-66 fuel pressure.
Cold start should be 55/62 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 55/62 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
If pressure does not come up with return line pinched or blocked off.
Go to fuel filter and hook a gauge direct to a line at fuel filter.
Pressure should come up to 75 or more and will hold after fuel pump is turned off.
If it leaks down there after fuel pump is turned off it is LEAKING BACK THREW PUMP CHECK VALVE OR PUMP MODULE LINES.
Post back your fuel pressure readings.
MT

Hi, Check Dist. Rotor


The 5.3 does not use a dist. or rotor....

i would first check fuel pressur regulator... pull the vacuum line off, if it smells like fuel it needs a new regulator. even if you don't see fuel, if the smell is there you need a new one. pretty common issue with the 5.3L

Going to try a temp sensor today, I'll let you guys know. Thanks for all the help

Going to try a temp sensor today, I'll let you guys know. Thanks for all the help

You are welcome .
Proper testing should led you to the problem.
Fuel pressure test and a good scanner check would be in order.
Good Luck

Going to try a temp sensor today, I'll let you guys know. Thanks for all the help

We in the auto industry call that "shotgun diagnosis" or "playin darts" hope it works for you.

We in the auto industry call that "shotgun diagnosis" or "playin darts" hope it works for you.

the DTC will not reveal a bad ECT reporting the wrong engine temp to the pcm/computer....some vehicle owners/mechanics ...because of the cost factor, which in this case is small will do this shot gun approach....a better method would be to measure the ECT resistance after the vehicle has set for a few hours/overnight and then measure the sensor resistance to the spec resistance for that temperature...

connector corroded pins etc...at the ETC...

the fuel side appears to have checked OK so this did have troubleshooting done..