P0304 P0443 white smoke misfire 07 Tahoe 5.3 4x4

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Jps0039

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This one has me stumped. Have done coil pack, plugs wires, MAF l, purge valve solenoid, and fuel injectors. The best advise I’ve gotten so far is to seal out an upper end OB2 reader to check compression and graphs. And to manual test fuel pressure. I’ve recently replaced the vent valve solenoid also and TPS. Could be bad CAT or MAP or fuel pressure regulator. Any and all advise appreciated I’m at my witts end. Live in Lee county AL if anyone lives close by. 07 Chevy Tahoe 5.3 4x4


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Jps0039

Jps0039

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Should also mention the misfire is bad at idle, shifts rough. Does better once up to speed blows thick white smoke smells like gasoline not oil.


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OR VietVet

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Gasoline will not blow out a "white" smoke. Thick white smoke indicates coolant in the exhaust therefore pointing to the likelihood of a damaged/blown head gasket. I am very surprised that with all this misfire problem that you have not done a compression test yet. That test should pinpoint the cylinder(s) involved and the source of the misfire. What does the oil look like when you remove the dipstick? how about the oil fill cap when you remove? Coolant tank inside? Using coolant? This will also effect the catalytic converters and the oxygen sensors. Do you have any codes?
 

exp500

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Put Noid lights on your injectors and watch..... My guess is you have a pinched wire grounding an injector or many injectors.
 
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Jps0039

Jps0039

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Thanks. Pops and I are going to try this next got an old one from my grandpa hopefully she still works. Know anything about overriding the AFM read that it’s potentially stuck on four cylinders


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Jps0039

Jps0039

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@PNW thanks for the response. Yeah I’m self taught and still learning. Never done compression test before but will give it a go. The Coolant levels are steady which lead us to rule out the head gasket. Oil is being burnt faster than normal.


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OR VietVet

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Oil smoke is blue, coolant smoke is white and too rich fuel condition is black. If there is another form of "thick white smoke" I need to be taught about it.
 

exp500

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PNW Vietvet- my education on white smoke came from a mitsu I bought way cheap. Owner said all he did was change spark plugs and it wouldnt run. I got it started, filled the whole shop with white smoke before I got it shut down, about 15 seconds. Scared the bejeebers outta me (seen a few vapor clouds light off in my past). Good thing air compressor didn't start up.Took another 10 minutes to air out shop so eyes didn't water. Found Injection harness pinched flat under intake manifold grounding injectors for full flow. Thats why I suggested noid light. Funny how much smoke will come out exhaust with an engine runnin. Also- you're about old enough to remember "Bug Trucks" aren't ya?
 
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Jps0039

Jps0039

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My dad corrected me and said thick ***** smoke would be like a sceeter truck. This is just regular white smoke. I will inspect the lines further and make sure there’s not a grounding issue. Thank all y’all for the responses. I will be relived once this is resolved until the next project.-JPS


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OR VietVet

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Oh yea, I know about the "killing bugs" smoke screens out the tail pipe. Hope you find the problem at the injector wiring.
 

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