P0172 95 4.3 vortec running rich need help
September 11th, 2018, 10:56 PM
#21
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Rats,so the vacuum leak for 02 test will show,(a)02 is working or not,right now it's .8 or so,with leak,hopefully it goes down to .2,so if it drops(b)pcm?
September 12th, 2018, 7:03 PM
#23
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Updated my software for my scanner today and did the induces vacuum test. It didn’t change the fuel trims. But I did find out that the catalyst is toast and is more than likely partially clogged and causing too much back pressure on the engine. I suspect at this point that it’s causing incomplete combustion and not slowing enough fresh air into the cylinders and causing the rich running condition. So for now the project is on hold until I have the time and money to replace the catalyst.
September 12th, 2018, 7:06 PM
#24
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I also plan on changing both 02 sensors out with the catalyst. At this point everything upstream checks out good. So I’m honestly hoping the new sensors and cat will be the solvation to the code coming back.
September 12th, 2018, 9:27 PM
#26
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September 18th, 2018, 11:14 AM
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Ok so
cleaned out the Cat and surprisingly it worked to stabilize it because it was fuel soaked and not damaged I lucked out on being able to clean it out. I just used a garden hose and simple green soap in a bucket and then used my vacuum / blower to air dry it out before putting it back into the truck. But it still has the fuel rich condition. Surprisingly enough I found a simple and ingenious way to check the fuel regulator on the vehicle using an air gun. and will post the link.
cleaned out the Cat and surprisingly it worked to stabilize it because it was fuel soaked and not damaged I lucked out on being able to clean it out. I just used a garden hose and simple green soap in a bucket and then used my vacuum / blower to air dry it out before putting it back into the truck. But it still has the fuel rich condition. Surprisingly enough I found a simple and ingenious way to check the fuel regulator on the vehicle using an air gun. and will post the link.
September 18th, 2018, 11:19 AM
#30
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It actually worked. Sprayed the face of the fuel pressure regulator with air and fuel mist was expelled from the vacuum hole proving that the vacuum diaphragm has a pin hole leak. Next step is to replace the regulator sometime this week and see if that solves the problem.