P0172, P0175 too rich, 07 6.2 about to throw in the towel

[chucksrt]

Regulator is in the tank on this one. Single line - returnless system, non-DI. The data here just confirms the rich condition, but doesn't tell us much else.

 

Is this a flex vehicle? I don't see it in the parameters, so I don't know if that's the fault of the tool, or that the truck isn't flex ...

It is not a flex vehicle. The fuel tank pressure sensor, coolant semsor and the o2 sensors are the only things i haven't replaced. The o2's seem to be switching when checking live data. I did not pay notice to the coolant temp readings.

 

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[wildcatter]

Your fuel tank vent is plugged.Remove the vent filter and solenoid and clean both.Also check to ensure the solenoid is working.Check the vapor canister as well for plugging or flooded.

[chucksrt]

Your fuel tank vent is plugged.Remove the vent filter and solenoid and clean both.Also check to ensure the solenoid is working.Check the vapor canister as well for plugging or flooded.

Could this also cause an extended crank? I started my car after sitting all day and it cranked for a while before it started. And the pending code (P0172,P0175) came on just as i started driving.

 

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[wildcatter]

Shouldn't cause extended cranking,but definitely filling problems.Since you have both issues, I would check to see if you are getting raw fuel in the vapor line from the tank to the engine.

[Jsdirt]

A plugged fuel tank vent would starve the engine of fuel. He has the opposite problem. A soggy charcoal canister, or raw fuel in the line would definitely cause his issue though.

[wildcatter]

Every plugged vent I've worked on showed no signs of fuel starvation to the engine.i believe the vent in the cap would prevent that from happening.

[Jsdirt]

I think I'm thinking of a different vent than you are talking about. You must be talking about the vent that allows you to fill up without gas puking out of the filler neck. I was thinking of the vent on the charcoal canister that lets the tank breathe (in only), or cap, if that's where they put it now.

[chucksrt]

I ordered the EVAP vent valve assembly so i went out last night to drop the spare tire so i could be ready to install it when it came and i noticed the smell of raw fuel. As my luck would have it the spare is seized and won't come down! So i need to find a way to get the spare out of my way so i can replace the vent valve and find the source of the smell

 

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[wildcatter]

The safety lock on the GM spares are awful. The lock is supposed to release when you crank the wheel up. They always stick. I have gotten some to release by cranking the wheel up and whack the end of the winch cable that holds the rim.Use a hammer.That will usually jar the lock loose so it can be winched down.Good luck. I have had to cut the cable with a torch a time or two.

[Jsdirt]

Yep - just about all of them come down with the fire wrench in this part of the country.

[chucksrt]

I just finally got my spare down and will brr replacing the vent valve assembly, but i wanted to know if that could cause it not to start? It has an issue that is getting worst. If i drive and turn it off and let it sit for 20 minutes or so it will have a really hard time starting initialy. If i turn the key off and restart it it will fire right up. Almost as if it doesn't have fuel. If i drive and stop and restart it 5 minutes later it starts right up. The only codes are the ones i have mentioned already.

 

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[Jsdirt]

Not likely unless the tank is filled up until it's coming out the filler neck, and the valve failed at the same time.

 

From here it sounds like you may have a failing fuel pump. Get a pressure gauge on there, and see where it sits at idle, snap-throttle, and shut down. Pressure should increase slightly on a snap, and hold steady for at least 5 minutes when shut down. 55-60 is what you're looking for if memory serves correctly ...

 

Thing is, normally a failing fuel pump will throw lean codes.

[chucksrt]

I was able to replace the vent tube assembly. Went fairly smooth. When i drove it i noticed that the service stabilitrack light and check engine lights were out. They were pretty consistant before. The truck did hesitate to start however. But it did. Drove it a couple of times and sure enough the service stabilitrack light came on a couple of times. I did not recheck the codes but i am sure it is still for running rich. After driving it the check engine light has stayed out although i know there are pending codes. But start up is tough. I am going to buy a fuel pressure guage tomorrow hopefully. It seems like the fuel is bleeding down, but i know the injectors were just done and tested so i am sure the only other piece is the fuel pump. From what i have seen, it looks like tje regulator is built into it as well as the fuel tank pressure sensor. I cant imagine how that could be related to the P0172, P0175 but i hope it is for my pockets sake!

 

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[wildcatter]

Have your filling issues gone away?

[chucksrt]

Have your filling issues gone away?

I have not gilled up since. I was afraid to fill up then have to drop the tank to replace the fuel pump.

 

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