Thread: vac leak i think?

Ok so at idle my ltfts are at 16.4 which means vac leak.....got some carb spray and sprayed every possible leak area......no change in idle.....wtf i recently put in aluminum lim gaskets with the l32 lim and genv and im running a silicone gasket on sc and tb adapter plate......im stumped.....i guess it could be on the bottom of the tb since i couldnt get alot of spray up there....

I'm having the same problem. Car idling high, checked everywhere & can't find the leak. Car has a new motor w/ aluminum LIM gaskets. I'm leaning towards both of us having a leak in the LIM gaskets. As the leak hasn't been visually identified...

I had the same issure with spraying and no idle change replace your the Vac line harness from your MAP,SC Snout,Fuel Pressure Regulator, BBV Solenoid

can buy the complete Vac line harness from GM for like 26$

What is the serv no on your pcm? If its a 01+ PCM it could be the dreaded cat diagnostic test that makes you run +16.4... but thats only if you have a 01+ PCM and you run a rear o2 sim. Anything done to the rear o2 sensor?

Also, from my experience ... a really bad MAF tune can do that. I saw that after I cammed my car.

Originally Posted by Lawngoose

What is the serv no on your pcm? If its a 01+ PCM it could be the dreaded cat diagnostic test that makes you run +16.4... but thats only if you have a 01+ PCM and you run a rear o2 sim. Anything done to the rear o2 sensor?

Also, from my experience ... a really bad MAF tune can do that. I saw that after I cammed my car.

well i have a half ass maf job on my car until i get it retuned, i just have a basic lq4 bin on it and my inj. flow rate increased for the 65#'s, could i get this from running pig rich, my exhaust smells rich....?.....its only +16.4 once the car heats up.....if my LIM gaskets are leaking can i remove and reseal without ruining them? i got a 00 pcm with no rear o2 and codes deleted.

Originally Posted by matt5112

if you have the stock cam you should still have around 20 " of vacuum.

You got a boost gauge right?

well i have a half ass maf job on my car until i get it retuned

I bet that's not helping, since your MAF values correlate with your LTFT's. When you get your MAF straight... start a MAF tune, with the correct values for a LQ4.

Originally Posted by Lawngoose

You got a boost gauge right?

well i have a half ass maf job on my car until i get it retuned

I bet that's not helping, since your MAF values correlate with your LTFT's. When you get your MAF straight... start a MAF tune, with the correct values for a LQ4.

stock cam, 1.95 rr and yes i got a boost gauge it sits right at -20 at idle......i have the correct values for an lq4 but none of them have been altered i just put it on the lq4 so it would start up and idle i have done any "tuning". i having a friend do the nitty gritty tuning.

i didnt rtv the gasket guides across the valley area tho....i only did the gasket pieces! do i need to rip it apart and re seal that area?

Ok, according to your boost gauge it doesnt sound like a vac leak. Just a wack MAF or tune.

Originally Posted by Lawngoose

Ok, according to your boost gauge it doesnt sound like a vac leak. Just a wack MAF or tune.

this.

Originally Posted by Bio248

this.

ok good.....what would my boost gauge be showing during vac leak how far off would it be?

Originally Posted by BoostJunki3

ok good.....what would my boost gauge be showing during vac leak how far off would it be?

You would have less vacuum ...

Originally Posted by Lawngoose

You would have less vacuum ...

lol why thanks.....would it be alot or very minimal? like 18 or 10 is what im getting at.

my maf tune is not even a tune lol we just re entered the hz numbers for a lq4

I would depend on the size of your leak... I would think. I think its your MAF Table. Get some one to help you MAF Tune it.

Weird how it sits at like 5 and 6 when i first start....the minute the motor is hott it shoots right up to 16.4

youre seeing the transition from open loop to closed loop.

Originally Posted by Bio248

youre seeing the transition from open loop to closed loop.

ok so your def thinking i have no vac leak then? thank god i just put the shyt back together and didnt wanna tear it apart.....i had to torque the SC bolts to 14 ft/lb instead of 17 ft/lb due to the silicone gasket....would u guys reccommend oem gaskets over silicone ones?

i always liked OEM gaskets, but if its sealed then i dont see a reason to switch.