A buddy of mine is having a fuel trim problem and the tuner thinks it is either a intake leak or low fuel pressure.. So we are going to try and find the leak today, any tips/suggestions/advice to finding a intake or vacuum leak?

I was thinking of hooking up my laptop and logging idle fuel trims, STFTs and LTFTs and then hose the intake down with carb cleaner and seeing if the trims change... Sound like a decent idea??

 

That's what I would try first. I've heard (never experienced) that you'll be able to hear a change in the engine sound as well when you do that.

 

You should be able to spray some in specific areas ( like by 1/3, 2/4, 5/7, 6/8) and the idle will raise . That way you get a better idea where the leak is.

 

Thanks guys, we will give it a shot this afternoon, hopefully we find the leak...

 

Old school, use a burnable gas around the intake, and listen for the motor or rev up...i hears it dangerous, but oh well!

Dustin

 

Mmmmmm, I think I will pass on pouring gas on a hot engine...

 

No like a gas gas, not liquid gasoline, like a butane torch (not lit of course)

Dustin

 

Ahhh, that makes a little more sense....

 

When my intake was leaking long fuel trims were max out at 25%. Try tightening up the intake bolts 1 or 2 turns see if the Long fuel trims go down. I just replace the gasket and it solves my problem.

 

Carb/intake cleaner is what I've always used...