stall under boost ,need help

[jose]

just installed a 3" borla straight through w/test pipe on my tta & in 2nd gear while cruising at 35ish - 40 mph,if i need to go for a sudden pass or accell.enough to fly past a few cars the rpms will shoot past 4500 and the boost will shoot up as well but the car wont launch but if i dont give it FULL accel,just half throttle the boost ,rpm and the car will work as one.This only happens while i am cruising down the road at 35-40 and and for whatever reason i need to pass someone or just to feel some power,i'll accel.almost fully and it will happen,so i let off the gas.Doesnt bogg or miss, just doesnt move like it should .I could drive all day and all week and the car shifts like it should.only under this circumstance does this happen.I dont know if it is just a coinsidence that this started happening after my exhaust install.I checked all trans.shift cables,fluid good,(tranny rebuilt about 15000 miles ago),new wast.sol.,all new ignition,new maf.What else should i check? any and all replys would be much appreciated.THANKS!

 

[fubar2.5]

What is your knock count/retard when this happens.

 

[WIKEDV6]

How much boost are you hitting when this happens, it sounds like you are over boosting, check all the vacuum hoses, especially the one on the side of the compressor housing.

Good luck
Prasad

 

[QuickWrench]

Does this happen when you leave from a dead stop, i.e. launching the car under Wide Open Throttle?

 

[jose]

Thanks for your replys guys,couldnt get back sooner.I or we just had kid #4 this morning.to answer Fubars ?,i will check maybe tomorrow evening with direct scan,Wicked 6,imagine cruising at 35 mph down your favorite blvd.and a loud mustang creeps beside you,when you go to hit it ,to take him your rpms shoot well past 4500,4700 (i let off the gas at this point) and your boost will follow up to past 16,18 lbs.but youre still sitting there.But if i accel.slowly first and than nail it its fine.I checked all hoses and or connections.As for Quick Wrench,no it will not happen under w.o.t from a dead stop,or i could be doing 50,60,70.etc.mph and it pulls super strong like it should.



Thanks for your help gnuys

 

[MistaScott]

I used to stall out under boost. I replaced my old nasty vacuum hoses and voila, no more stalling.

 

[WIKEDV6]

What kind of down pipe/ waste gate setup do you have?, maybe the puck or the waste gate is getting stuck!

 

[jose]

I will tripple checck all hoses and i am using the stock dp and wastegate.Does this sound like a trans problem to you guys?the car shifts are correct in any other driving range.if i am cruising at 35ish-40 mph and lightly give it a few lbs and then floor it, the car shifts fine,perfect.but if in the same situation i needed to move.very quickly if i accel.more than lighty both rpm ant boost will shoot up with the car not mooving with the boost,like a very late shift. It seems like the car wants to shift as i am letting go or the pedal.

 

[thunder'n6]

Readjust your tp cable. Check to see if there is any resistance on the cable with the engine off.

 

[trbojo]

don't know much about trannies, but it definitely sounds like the problem area. maybe a slipping band or misadjusted cable. low fluid?

 

[jose]

I have tried just about every setting on that cable and still nothing.The more i try to understand this i think i am going to have to drop the trans.pan this weekend.



Thank all of you guys for your help.This forum is one of if not the best auto forums on the net.

 

[thunder'n6]

Before you pull the trans. Find a dealer for a company called BG. Try car dealer first. They make a product that takes the varnish off of the moving valves in the valve body. Don't use any off the shelf stuff , use it from BG. I Have used it on My GN with great results.

 

[jose]

Thanks Thunder n6, will try just about anything .