[Jimbofoshow]

This 5.3 Yukon was driven nicely in the shop. No problems at all. Soon as it crossed into the shop door it dies and hasn't started since. Pull the plugs and they are covered in fuel. It is sparking. Fuel pressure is at 45lbs. (I know its low, but should still try to pop off I would think). Only codes were p0171, and p0174. Don't make sense. If its flooding then it shouldn't be lean. I'm not really relating these codes to the current situation. Any ideas?

 

[Pikey]

If the pcm is reading lean then it will dump more fuel in an attempt to fix the lean mixture. Check for exhaust leaks. A leak in front of the cats can give false lean readings.

 

[Jimbofoshow]

Can't do much checking for exhaust leaks at the moment. It will not run.

 

[Pikey]

If you put the gas pedal on the floor and hold it there while you crank it should put the truck in " clear flood mode" it will not pump any fuel into the motor

 

[Jimbofoshow]

Been trying that. Every now and then it will try to pop off but barley.

 

[Jimbofoshow]

I don't usually have much problems with things like this, but this thing is making me look really bad.

 

[Jimbofoshow]

Tried a mass air too. Got a fpr on the way. It was leaking through the diaphragm. Not that I think that is the problem....

 

[Pikey]

I was just going to recommend checking the fpr.

 

[Jimbofoshow]

Got it in my hand right now. About to pop it on.

 

[Jimbofoshow]

And that would be a negative.

 

[Jimbofoshow]

Fuel pressure ten pounds low....it should still fire up and run bad huh?

 

[Pikey]

Another thing is the coolant temp sensor. If it is bad it will tell the PCM that it is -40 and the engine will flood from all of the fuel dumping in. If you remove the connector, check the resistance of the temp sensor, if it is open then you have your issue. It is located on the drive side between the front 2 cylinders

 

[Jimbofoshow]

Yep. I checked that. Its reading ambient temp. Its not at default.

 

[Pikey]

These trucks don't like running on pressure that low. But I figure that it should at leaAt fire up for a second.

 

[Jimbofoshow]

Uhhhhmmmmm......just unplugged coolant temp sensor and my actual values still read 55°.

 

[Jimbofoshow]

Uhhhhmmmmm......just unplugged coolant temp sensor and my actual values still read 55°.

There it goes....-38....now that was a delayed reaction.

 

[Pikey]

I am going to tag @j cat here. Maybe he is available to help out. He is pretty good with diagnostics of these kind of things

 

[Jimbofoshow]

Thanks!

 

[Pikey]

Also @99'HEARTBEAT is a magician when it comes to locating tsb's. Maybe there is one out there, maybe not...

@99'HEARTBEAT , Sorry for dragging you into this one again mike!!

 

[Pikey]

If @j cat makes it here and @99'HEARTBEAT has time to search around today then hopefully we can get s resolution for you