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Old 11-21-2010, 07:24 PM   #9
chrisfrom nj
 
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Join Date: Feb 2005
Location: west orange nj
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Quote:
Originally Posted by 91chevywt View Post
It's worth checking the cat out...bad fuel spiders can cause rich conditions that will wipe out the catalytic converter in a hurry. Tap on the outsize of it with a rubber mallet and see if it rattles.

You say fuel pressure is good...you didn't check it only by squirting a little fuel out of the test port right? The CPI motors are very sensitive to fuel pressure, as they require pretty high pressures to run correctly. I forget what it was exactly though...but i'm sure you could find out online.

You may have a leaking poppet in the fuel spider or a leaking fuel line under the upper-intake manifold. Either of these issues will allow the truck to start very easily and idle or warm up fine, since the engine can handle the extra fuel, but once it warms up it'll have no power cuz it's too rich.

It would be worth it to look at the o2 sensor as well. If you have over 100k on the truck and it still has the stock sensor, it would be worth it to replace. I think theyre like $25-$30. But investigating the fuel spider is the best thing to do since they are so troublesome
im going to check the cat tomorrow when i have it on the lift i pulled off the vortec cover and looked at the injector everything looked the same it was black not clean i checked the fuel pressure with the fuel pressure gauge it said 55 at idle and it goes up when you rev it the think that gets me is if its 55 when you turn the key on without starting it then it drops to 15 when the pump shuts off im getting a new o2 tomorrow the truck has 99,000 miles
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