Chasing an intake leak

[Eneme]

Looking for some help diagnosing an intake leak. About 6 months ago my TPS went out (had ghetto launch control since it always wanted to be at 3k everywhere) and decided as part of some upgrades that I wanted to do that I would get a new TP/Plenum from accufab. Little while after that I got a pretty nice steal on some LT headers/Catted X-Pipe and got those put on as well.

During that time (don't remember if it was happening before the TPS went bad) I noticed the car would take awhile to come down anytime you blipped the throttle even a little bit and would hover at 1700 before dropping to 1k (which is what the car has always wanted to idle at as long as i've had it) I figured this was either from the TPS or new TB/LTs and was waiting awhile before i could get a handheld tune from AM. However the tuning guys said the cars problem was that it had an intake leak somewhere at idle, though doing a step test datalong and normal driving, they said it seemed to look fine.

I've tried spraying around the intake ports everywhere (albeit with brakeclean as i don't have starter spray) and havn't been able to find any jumps in RPM anywhere. Any suggestions where to look/ways of isolating the problem?

 

[StalkerStang]

Any codes or check engine light? Is the IAC dirty or stuck partially open?

If you don't find any obvious leaks, I would do a base idle reset.

 

[Sluggie24]

Brake clean will work to find a leak as long as it's flammable brake clean. One of those Eco friendly non flammable ones won't work. Starter fluid will work better though since it's super flammable.

Did you try spraying around the intake hose between the MAF and Tbody? Around upper intake? In engine valley under lower intake as well as on top of intake? Injector seats? All vacuum and breather/IAC lines? If there is a leak those are the only areas it could be at.(assuming no intake cracks)

 

[Eneme]

No check engine light codes aside from p1000 code if i plug the reader in but that's from LTs im assuming since it doesn't actually pop the CEL light itself.

How would i go about doing a base idle reset? And i'll give the IAC another check. Think i replaced it when i did the TPS sensor though just to have both replaced.

And I sprayed pretty much everywhere I could think. I didn't check in engine valley/ injector seats. Only thing I remember is there did seem to be some kind of response around the TB plenum/intake seating. But very very minimal if i recall. Will have to give that another look when i get some actual starter fluid.

 

[StalkerStang]

A P1000 indicates all the emissions monitors have not passed yet. This typically shows up if the battery has been disconnected for a little while. But it will set other codes eventually if there is a fault present.

 

[StalkerStang]

Before doing a base idle reset you have to make sure there are no other faults or leaks. If not it won't help.

If you can reset your KAM then do that, if not leave the battery disconnected for 15 min or so to clear any learned data in the PCM.

Start the car with all the accessories off and let it reach normal operating temp. With it idling on its own, disconnect the TPS and IAC. If the car dies, then you adjust the idle stop screw on the throttle body open more. If it still runs, then adjust the stop screw to close the throttle plate some. Repeat as necessary. Each time the car dies, and you make an adjustment, plug the IAC nad TPS back in before you restart it.

Essentially you want the car to barely idle on its own with the TPS and IAC disconnected. Once you've found that spot, shut the car off, lock the jam nut down on the throttle body and plug the sensors back in before you start it back up.

 

[Eneme]

Thanks for the info man, i'll give it a shot when I have some time! I'll make sure to grab some starter fluid first just to give it another once over to make sure there is no obvious leak before, but will definitely proceed with that after.