was driving home one night and noticed i wasnt boosting over 5lbs, normally i would think limp mode, but theres no CEL or pending codes, if it were a bad MAF sensor it would throw a code correct? im HP tuned by a local guy here in long island, he says its not the tune but something else ?????

 

Did you do a boost leak test?

 

Pull your battery. see if that fixes it. i had the same problem before and I had to pull my battery. Could also be a bad vacuum tank

 

Did the battery didn't help, next is boost leak, but would a boost leak really cause it to lose 20lbs of boost ?

 

Usually it makes the car run like complete **** but not limit you to 5 psi unless you had a massive leak.

 

Is your BPV connected? IIRC the BPV not connect limits you to 5-7psi. Check all your lines and ensure they're connected properly.

 

Yes check your BPV. Make sure nothing is torn. a leaking or bad check valve on the vacuum tank will cause this issue too

 

It is on WG spring pressure only. I would suspect either the boost solenoid is stuck open leaving the WG constantly open, the BPV diaphram is leaking badly, or the check valve in the vac tank for the BPV is bad.

 

yes it can. i had a small boost leak for a while. turned out i forgot to tighten a hose all the way down... and after about a month it got worse and probably only losing 1-2psi at WOT, and after a while it would throw the car in limp mode and get 5psi. and when i drove it WOT in 5psi it would go down to 0psi lol....

 

i run a tial bov, with the vac line conected straight to the intake mani

 

Are you running stock intercooler?

Sorry for a dumb question. I didn't see it on your list.

 

do you have the ECP tune?

 

yea checked all the couplings there fine, and sry ecp? theres no selecting my tune, he made it so its always on

 

there is your problem...

contact vince, give him your VIN number, and let him know you want an ECP tune..

 

Wonder if you had a silent code that tripped 5 psi only cause of your BOV.

 

Often times a blown intercooler. Seams on the sides are known to pop.

Not saying that's definitely your problem but I've seen it happen a few times. Definitely sounds like a boost leak either way.

 

if you get the ECP tune and you still have 5psi problem...


what psykostevo said is correct as well..


even a small hairline crack on the fmic can give you 5psi or less

 

Did you check by doing a proper boost leak test? visual/by hand doesnt cut it. You have to put pressure (15-20psi) and hold it there and spray soapy water or leak tester (Snoop is a brand my work uses, not for cars but mining processing, dont want deadly gases leaking at fitting). IIFC there is a thread about how to perform a boost leak correctly.

 

soapy water test sucks. just hook up a fog machine to your upper charge pipe, and make sure your throttle is closed. lol... easiest way imo

 

Snoop def works better than soapy water, and is cheaper than a fog machine.