need a pro- 2001 silverado p0121

theman
Posts: 5
Joined: Sun Sep 07, 2014 7:32 am

Re: need a pro- 2001 silverado p0121

Unread post by theman » Sat Sep 12, 2015 12:40 pm

The $.12 problem So I was wrong after about 50 miles light came back on. At this point I decided there has to be an air leak somewhere. So I bought me two cans of carb cleaner and a piece of hose went around the entire engine. Check every fitting everything. Couldn't find a air leak anywhere. What I did notice is the oil fill extender tube did not fit very well. The O-ring was bad I also noticed. That right next to the filler tube is an air intake hose that connects to the throttlebody just before the blades It's meant to supply fresh filtered air into the engine and then the sucked out by the PCV valve But because the O-ring was leaking it was now sucking air into the throttlebody. Bypassing the mass airflow sensor Which is more than likely throwing that reading off and was what was causing my code Also the PCV valve it would now be sucking air directly through the leaking O-ring. So basically what I figured out it's because that O-ring was leaking it resulted in a massive air leak At least that's what the computer thought The engine looks at the position of the throttle the air coming into the engine and the RPM if those three don't match then we got a problem. I'm pretty confident that was the problem the truck is never ran better I'm at 75 miles right now on my way to get my state inspection. Thanks

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: need a pro- 2001 silverado p0121

Unread post by carriedi » Sat Sep 12, 2015 11:13 pm

The IAC counts should have shown a low count for the unmetered air. that's what the IAC does. It's a vacuum leak that is controlled by the computer. Glad you found the problem. Hope all goes well now. Happy driving.
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