LSJ very low boost pressure
Currently GM stage 2, k&n intake. i just put a 2.9" pulley and ported my m62. i had the zzp ls4 tb with a zzp canned tune which ran great earlier this week until gm fucked up a crank relearn by reflashing the shitty as **** gm tune back into my pcm - im currently waiting for my zzp pcm to be sent back. Anyways, tonight i get a bank 1 too lean code and then notice my boost pressure is extremely low especially in higher RPMS. im still boosting but with very little boost, low end power isnt disabled totally as the car is still driveable. at WOT boost is basically disabled which is making me wonder about my bypass actuator. If anyone is farmilliar with this issue or has experienced it themselves id appreciate some feedback!

 

How low

 

Your runing a stock tune on a deacently heavy modded car

Common sense says dont even drive it at all till your tuned


Im suprised with all that extra air flow and fuel with those injectors your not in some kind of limp mode
For the car not knowing wtfs going on

 

well when the zzp tune was deleted i reverted to stock TB. so the 2.9" pulley and ported supercharger are the only increased mods on my stock gm stage 2 tune. now today it will roll over but wont keep an idle, all hoses and everythieng are plugged in right and i even cleaned my throttle body. definitely leaning towards a fuel issue now

 

You are running larger injectors on a stock tune. Do not drive the car until you get an updated tune on there.

 

GM didnt flash you back to a stage 2 tune, they flashed you back to factory.

Stage 2 tunes cames as a part of the stage kit. A dealer cant just look it up and flash it on, it has to be purchased from the kit.

I would be very surprised if the dealer went out of their way and sourced you a stock GM stg2 tune...

 

In the summer i got a stage 2 through GM. That tune would be in the system for my car. but regardless i had the stage 2 pcm and just plugged it back in while my zzp is getting flashed. Now i need to feather the throttle to keep it running. theres either a lack of fuel or a considerable vacuume leak of some sort.

 

The tune is not in the system.
So you have more than 1 PCM?

 

yeah i kept my gm stg 2 pcm when i ordered my zzp one.

 

So your car is running shitty on a verified gm stg2 tune then?
Did you case relearned when you swapped PCMs?

 

Do not go WOT. I repeat do not go WOT. What injectors do you have in it? GM stage 2 is not designed for a 2.9 pulley... I would try to not drive it until you get your PCM back or a tune.

 

a 2.9 on GMS2 isnt going to kill anything and it wont make the car not idle! There are hundred's of LSJ's on this site running a GMs2 with 2.9 and ive even seen 2.85 in the past, Id have the tune looked at cause just a PCM swap should not affect idle! it could be pulling timing/boost due to a leak use some carb cleaner on under your hood.. If the idle raises when sprayed you have a leak! ANy other codes? Lean bank 1 is usually an intake and it should still run okay with that as my old LSJ had the same code with a K+N!

 

You have an air leak somewhere, something got disconnected or broken between the MAF and intake. Check all the hoses around the TB and all seals, normal vacuum leak procedures apply.

You can remove and cap several of the EVAP lines and such for diagnostic purposes. Don't leave them like that though.

 

were you losing alot of boost? i hit about 8psi in third last night which was better than the other night. im thinking it could be the supercharger gasket as it was a bit bent when i reinstalled it after removing the blower. the brake cleaner test was too hard to identify the leak and i did the boost by pass mod with no success as the car died when i cut off the vacuum source.

 

wasnt required cause its original pcm / original vin.