speeddemon7

Ok ill try and keep it as brief as possible.This issue became apparent once I changed my old injectors with new ones.Its seems that the car has a problem accelarating once the boost is dumped in second gear.
For example im at a stoplight and I take off in first.Car accelarates fine.I hit second gear and the car accelarates fine all the way up to redline but If I let of the gas and the car is just cruising at 4000k or above and I try to accelarate again the car is extremely sluggish and it really struggles to get up to 7 or 8 psi.Also when I let off the gas again the bov barely makes a noise and then this really weird booop sound comes from the second intake or what could possibly be the second turbo.Whats really weird is that if I do let off the gas in second and I let the car rev down below 4000k to say 3000 rpms the car build boost normally once again.All of this seems to point to the secondary turbo control system.

speeddemon7

does anyone have any idea what could be causing these symptoms?

legal-z

i would say you definitely have a vacuum leak. where you ask? if i could answer that i would be a rich and retired from repairing third gens.

speeddemon7

I thought so.I have a few leads.But I couldnt find it by spraying carb cleaner around.I tried and no jump in idle at all.The car runs very strong otherwise though.Weird.Definately weird.

alberto_mg

having a similar problem myself. difficult getting boost in secondary. check to make sure your solenoids are connected properly and that you didn't crimp a vac line somehow. how many miles on the car? also check the thread in the archives for a few things to check. what a biatch...

911GT2

It sounds like some type of CCV problem to me. Check out the autosportracetech troubleshooting page (sorry, I don't have the link handy, I think thats the name of the site though).

Basically the CCV adds secondary boost into the intake track. Sometimes the solenoids that control it aren't working properly, and it won't close again once its opened until it sees a whole lot of vacuum for a decent amount of time (as would happen if you let the engine rev down to 3k rpm or so). If it stays open, you get serious turbo lag anwhere under 4500 rpm, as you've described.

speeddemon7

hey 911.thanx for the input.I really appreciate it.One thing though.I get the turbo lag after the boost has been released and I try to boost again while being in the same gear.Also what is the ccv? Is it the charge control solenoid? thanx.

speeddemon7

im seriously thinking that when I put the car back toghether after changing out the injectors I may have crimped a vacuu, line somewhere in the rats nest.I guess Ill have to go back and take the uim off and check every vacuum line to make sure it isnt pinched down.

legal-z

it's constant crap like this that drove me to go non-seq...and i'll never go back.

speeddemon7

do you mean a single turbos or the twin non sequential modification? how does the twin non sequential setup work? does each turbo produce like 5 to 6 psi a piece?
How do they spool up speedwise compared to the sequential twin setup?

legal-z

i'm using stock twins that are set up to run non-seq. each turbo spins all the time and they produce boost just like functioning twins would over 4500 rpms. spool up is a little slower. i get full boost at about 3500 rpms. do a search on this board and you will find plenty of links/descriptions/how-to's, etc. if you want more info, pm me and i'll send you what i have.
andy

911GT2

Here is the link I was talking about earlier. http://www.autosportracetech.com/RX-...leshooting.htm

A malfunctioning CCV (Charge Control Valve) would cause the exact problem you describe. If it sticks open, your turbos will remain in parallel mode, or non-seq mode, which is basically that they are both providing boost all the way through the rev range. As such, it takes a bit more time to get them spinning fast enough to produce any boost.

If you switch gears, the CCV sees a lot of vacuum for a while, which may or may not cause it to unstick.

Try this: go full throttle up to like 6k rpms, off throttle till it falls back down to about 4k rpms, then go full throttle again. If theres a lot of lag as you described, quickly jump off the throttle then back on. That allows the CCV to see a quick burst of pressure/vacuum ,which should open it.

My real opinion: Go non-seq. Then you won't have to deal with all the sequential troubleshooting issues.

alberto_mg

non-seq sucks imo. **** happens no matter what. diagnose it and fix it.