ok i posted last night that my 67 camaro with a 5.3 and ls1 intake starts but idles up over 2000 rpm immediatly then after a minute or so starts to make its way back down to around 700 but something isnt right. im only pulling about 6 inchs of vacuum according to my gauge i hooked up and when i hit the gas it almost dies. im really really confused right now. i sprayed carb cleaner everywhere and didnt find much. the only placce i see it idle up when i drench it is around the throttle body. but its not but maybe a couple hundred rpm and i gotta seriouisly soak it down to get it to idle up any so im not sure if thats even it. so where all is the most common vacuum leaks. also what scanner tool do i need so i can check all of my sensors and make sure like the maf and everything is working right. who figures this one out ill buy a case of beer lol. if you need more info just ask any help is greatly appreciated

 

oh yeah i also got a error for the map sensor on the autozone scanner i borrowed. but i figure its caue im not pulling much vacuum

 

Assuming everything's connected up,

as it should be and the motors mechanically okay (no airleaks, stuck TB etc) You need to get hold of someone with either EFI-Live or HP-Tuners as you more than likely have some PCM issues.

 

exhaust leak or clogged cat?

 

well right now im running open headers but i dont think i have an exhaust leak. and i think i have a vacuum leak cause of the low vacuum but cant figure out where

 

This is definately a Leak. I would make sure there isnt any leaks after the MAF. Check the back part of the intake where there are three connections. The MAP sensor, and two tubes. I believe one is from the brake booster and and the other one is a pretty thin one. If that doesnt work, check your fuel pump and fuel filter.

Is there any popping when you step on the gas?? Double check your spark plugs/wires.

 

Vacuum that low usually means mechanical. Since you've already sprayed I'd do a leakdown or compression test. If the dry compression test fails do the wet as well and report your results. When you have 6 in vacuum your MAF is your least concern. You haven't reported enough info to get much help without a rabbits foot.

 

ok what else do you need to know ill try to answer questions. does anyone know where i can get an intake pressure tested around bowling green ky??

 

It would help to know mileage and driveability issues. What mods and have you used dope or not? When you say you want intake pressure tested do you mean using a pressure transducer? That's pretty heady stuff and requires not only the transducer, but a fast o scope and someone why can interpret the waveforms on the display. The First Look is used with the pico scope, but good luck finding someone that has those and can read the waveform correctly. Since you've sprayed the intake you're better off doing compression and leak down. Leakdown is more specific, but the First Look is amazing. It tells you everything without tearing the motor apart. Bernie Thompson of ATS sells an 8 channel oscilloscope with 2 time bases and pressure transducers. With that a leakdown will be a waste of time

 

Ok this is a 5.3thats completely stock with the exception of an ls1 intake and throttle body and I just mean is there a way to take the intake off and have it tested for cracks that could be causing my vacuum leak.

 

And as far as driveability issues it's never been driven before. Just finished the swap. And before anyone asks yep I had the computer done for a 5.3 engine and everything removed that I needed removed

 

Oh and about 80000 miles on engine bought from I beleive lkq. Or lqk I can't remember

 

You've basically done the test when you sprayed your intake. You could go one step further and have someone spray the intake while you watch your STFTs on bank 1 and 2. The STFTs will react more quickly than your idle speed. If you STFTs go negative when you spray you have a problem. The ECM is pulling fuel to compensate for the extra fuel that got in during the spraying. If the STFTs don't go negative your OK.