Hey guys i have a small delima here. Ok my SES light came on just the other day, so i decided to go up to a chevy dealership and the tech there told me that i have an intake manifold leak. Now the reason he says this is cause he threw the TechII scanner on the truck and said that banks 1 + 2 both read leanand my fuel trims are all messed up. Now i imediatley thought that I must have had an exhaust leak cause it sounds like one. When ever the truck is in park and i rev up the engine, I can faintly here a slight leak which sounds to me like it was coming from the flange where the shorty and the stock y meet together!! So the first thing i'm thinking is that my o2 sensors are getting too much air or not enough exhaust etc. But then he says that would make sense except the fact that the scanner read that there are two banks reading lean!! So my questions are 1: Is there a way that i can find out which one it is 2: Can anyone tell me if any of this makes sense and if not, what do you think it could be!?? Thanks Fellas

 

The Best Thing I Can Tell U From Dealership Exper. Go To Any Auto Part Store And Get A Can Of Brake Cleaner Are Use A Bottle Of Water And Start Your Motor And Spary The Base Of The Intake It Will Make The Miss Fires Go Through The Roof And You Might Even Make The Ses Light Blink The Motor Will Run Rough That Is A Way For You To Check It Intake Gasket Are Easy To Do Take About 1 Hour

 

Ok so i sprayed my intake manifold as much as i possibaly could and still nothing happened. No spudders no slowed fires no ses. So now what?? How do i know if its my exhaust which I've been thinking it was this whole time. I couldn't quite do the same thing cause it bubbles up as soon as it touches the ex. manifolds

 

Did you check the torque on all the bolts?

 

For the most part they're all prettty tight but i dont have a tprque wrench though so i dont know the specs. I did however tighten some of the header bolts up on the driver side!!! When i had the headers installed I had someone else do them for me cause i had no welder and i got the rest of the exhaust system thrown on as well!! Well i got an intake coming so ill change it anyway along with gaskets and O rings!! But as for the exhaust i still dont know what to do cause i cant tell which it is and dont wanna spend 100's of dollars trying to find out.

 

You may want to check you collector gaskets on a colder morning/night. I can see mine spitting out steam. Anywhere there is an exhaust leaking it'll be black around the area.

I hear that if the collectors are leaking, it can suck fresh air back into the exhaust, therefore throwing the front O2's out of whack.

 

Sounds good so basically when it gets cold tonight try it out and see if i can see the steam leaking out and if so then it should be black in the are or areas that are leaking!!?? Now i know this sounds dumb but collector gaskets, are we talking the smae gaskets im thinking of on the manifolds or am i just that dumb lol.

 

Boooyaaaa I found it unfortanatley i burned the living **** out of my hand! But its exactley where i thought it was. Exhaust leak where the shorty flange meets the stock y pipe. The gasket there is blown through, i just got far enough in there to see part of it hanging out of the flange. Anyway i reached my hand down there not thinking i just drove to work and wow oh wow is my palm jacked up!!! Anyway thanks guys for all your help, I still think the dealership was trying to screw me into buying parts i didnt need!

 

Holy **** your back. well glad you found it not where is the build up you promised me.

 

Hehe youll be happy to know that im breaking down the engine this weekend to take it to the mahine shop, the heads, valves and all, pistons rods and crank. Theyre all going hehehehe
And the valves, pistons, and rods are getting the heat treatment coating!!! Once it gets back its off to FLP for the 4l80e for the L5 upgrade, and I'm expecting this sometime around May. So mid summer ill be up and runnin N/A, then come christmas ill be runnin the turbo.... Oh new news though im gonna go with th wieand intake manifold with the direct port NOS 25 shot and 100shot dual stage!! Its on like donky kong