Secondary Boost Problem....
08-24-08, 12:17 AM
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Secondary Boost Problem....
Hey guys,
I've been searching for a long time now and have come up with nothing that matches my symtoms exactly. My car just started having a secondary boost issue out of no where and I have checked all the vac hoses and everything seems to be in check. I have also gone through the http://www.autosportracetech.com/RX-7/rx7stuff.htm website with no luck.
My problem is that my primary is boosting just fine but my secondary is kicking in at 10psi but then quickly falling to 5psi and then bouncing between 5 and 6psi. I was just hoping that you guys could point me in the right direction.
A few details bout the car would be that I do get a small cloud of greyish smoke at startup which only comes during the initial firing and quickly stops. My boost pattern is supposed to be 11-9-12 but has recently gone to 11-9-10-5~6....the car drives like normal just no strong kick when the secondary should come online(which is what is used to do). Primary boost is normal and strong but when the secondary should be coming online I am kind of getting a flat power curve feeling from the car. The car usually pushes 300+rwhp but now feels that I am making significantly less in the top end.
i am hoping that my turbos aren't toast and I see no reason for them to be bad. I'm hoping just a vac leak which I can't pinpoint in the rats nest. Maybe you guys could point me to a location that causes such symptoms. My vac at idle is around -16 which is how it's been for years, so nothing out of the norm there. The car for the most part sits in the garage (driven twice a week) and doesn't get any abusive/hard driving. One day the car was boosting fine and the next I'm not making full boost on my secondary.
Mods on the car are in Sig. Any advice or a point in the right direction will be much appreciated! Thanks guys
I've been searching for a long time now and have come up with nothing that matches my symtoms exactly. My car just started having a secondary boost issue out of no where and I have checked all the vac hoses and everything seems to be in check. I have also gone through the http://www.autosportracetech.com/RX-7/rx7stuff.htm website with no luck.
My problem is that my primary is boosting just fine but my secondary is kicking in at 10psi but then quickly falling to 5psi and then bouncing between 5 and 6psi. I was just hoping that you guys could point me in the right direction.
A few details bout the car would be that I do get a small cloud of greyish smoke at startup which only comes during the initial firing and quickly stops. My boost pattern is supposed to be 11-9-12 but has recently gone to 11-9-10-5~6....the car drives like normal just no strong kick when the secondary should come online(which is what is used to do). Primary boost is normal and strong but when the secondary should be coming online I am kind of getting a flat power curve feeling from the car. The car usually pushes 300+rwhp but now feels that I am making significantly less in the top end.
i am hoping that my turbos aren't toast and I see no reason for them to be bad. I'm hoping just a vac leak which I can't pinpoint in the rats nest. Maybe you guys could point me to a location that causes such symptoms. My vac at idle is around -16 which is how it's been for years, so nothing out of the norm there. The car for the most part sits in the garage (driven twice a week) and doesn't get any abusive/hard driving. One day the car was boosting fine and the next I'm not making full boost on my secondary.
Mods on the car are in Sig. Any advice or a point in the right direction will be much appreciated! Thanks guys
08-24-08, 12:40 AM
#2
Could also be a clogged cat if it's at higher rpm...how many miles on the cat?
Other than that, check your actuators and corresponding solenoids... turbo actuator, wastegate actuator, and the one in the y-pipe up top. Could even be an intake hose that's collapsing at higher rpm too...
Other than that, check your actuators and corresponding solenoids... turbo actuator, wastegate actuator, and the one in the y-pipe up top. Could even be an intake hose that's collapsing at higher rpm too...
08-24-08, 12:52 AM
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Nah don't think it's a clogged cat because the issue is from transition to redline so primarily the 2nd turbo and not just upper RPMs. The cat is a highflo bonez with probably about 10,000 miles on it, if not less. As far as the intake pipes go, I will check it out but I'm fairly certain it's not the culprit. Could it be a boost leak? because my coupler from my efini y-pipe to my intercooler looks a little funky but is less than 1,000 miles old (installed by PFS). And by funky I mean the metal clamp overhangs the end of the coupler itself. I would think that if it is a boost leak that it would affect the primary boost as well, which is functioning properly, so I have cancelled that out. As far as the actuators themselves, I've been looking at the brown actuator that is right below the intake pipes and it seems to be funtioning properly....
08-24-08, 01:01 AM
#4
Well, invest in a MityVac and get to work on the solenoids...
One note, the main actuator uses both vacuum and pressure to open...usually that can be the problem, I would start there. Oh and don't forget the check valves too.
One note, the main actuator uses both vacuum and pressure to open...usually that can be the problem, I would start there. Oh and don't forget the check valves too.
Last edited by PandazRx-7; 08-24-08 at 01:20 AM.
08-24-08, 01:32 AM
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it sounds like i have the same problem with the secondary turbo occasionally and it drives me nuts. i cannot find any leaks anywhere either. usually my second turbo kicks in fine. i have seemed to notice i have the boost problem (bouncing between 5&6psi) when i first accelerate hard with the second turbo only. i swear i have no vac lines popped off or boost leaks in intake tubes/connections. this problem is so frustrating because you dont know how the car will react when you step on the gas. i guess im down to the solenoids or actuators as the reason to my problem now. i was searching pettit's site and i came across their blueprinted charge control valve assembly that has me wondering if that might be it now. i feel at this stage i have eliminated all of the "cheap" fixes and now im down to playing the cat and mouse game with the actuators and solenoids...
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