Blue smoke and smells like gas

[Charcoalyukon04]

2004 yukon 5.3L 131,000 miles

A couple months ago I'd have to floor or pump the gas to start the truck. It would puff out a huge blue cloud that reeks like raw fuel. When the truck was warm, it would start fine, no smoke. While idling and warm, the exhaust smelled like rotten eggs. It's got a new plugs and wires as of this weekend.

Yesterday morning the issues started again. Only change is while running, the rotten eggs smell is gone. But it's still puffing blue gas smelling smoke on first start and having to be floored or pumped to start.

Ideas???

 

[Charcoalyukon04]

I should add, runs fine otherwise

 

[YukonandtheHOE]

Sounds like you havebad injectors

 

[rockola1971]

Yep this sounds exactly like a leaking injector. Easy diagnosis. Check fuel rail pressure with engine and pump off. Getting a check engine light?

 

[Charcoalyukon04]

I always have a check engine light. Truck eats knock sensors. So lord knows if there are any new codes. I have a scanner so I'll check.

I had a feeling it may be injector related. Seems like it's flooding itself out. Hubby says may be fuel regulator.. I dunno.

 

[rockola1971]

You should never have to push on the accelerator to get a fuel injected engine to start. (They arent like the old carburetors where you had to manually set the choke). Its all automatic. If you are having to hold the throttle down to get started and its really rich then the engine (most likely just one specific cylinder) is getting flooded and a injector stuck open will cause that. To see if an injector is stuck open just stick a fuel pressure gauge on the rail and see what the fuel pressure is at after 30-60 mins after the engine has been ran. If its substantially lower than 35-45 psi then you have a injector stuck open and bleeding the pressure off. Be very careful with this engine at that point. All that excess fuel will make its way into the oil and thin it out. This is potentially a catastrophic event waiting to happen. AKA-- Spun main bearing, cam bearing or rod bearing. Injectors are fairly easy to replace and run around $60 each. Easiest way to tell which one is the culprit is to spin engine over and let it start then shut it down immediately and start pulling spark plugs to see which one(s) are wet(gasoline). Those cylinder(s) are your culprit fuel injector(s).

 

[Charcoalyukon04]

I'm not vehicle illiterate lol. I know I shouldn't have to push down the accelerator to start it.

I'll start checking pressue. Thanks

 

[YukonandtheHOE]

I always have a check engine light. Truck eats knock sensors. So lord knows if there are any new codes. I have a scanner so I'll check.

I had a feeling it may be injector related. Seems like it's flooding itself out. Hubby says may be fuel regulator.. I dunno.

Eating knock sensors? Does this thing ping and detonate that much you swap knock sensors because it throws a dtc? A dumping injector will eventually melt pistons and burn out valves.. not to mention dilution of oil that will kill bearings and wipe out the CAT's..
what are your current DTC's?

 

[Charcoalyukon04]

It's been to the dear many times for throwing knock sensor codes. Even before I owned it. It's been an issue since 50,000 miles. Truck now has 131,000. The sensors and harnesses have been changed quite a few times now. All is good for a few months and then they go back to throwing codes

 

[afpj]

I'm curious what your fuel trims look like. You got a scantool that can read that? I bet they're pretty wacked which would help the diagnosis.