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-   -   i hate my boost system (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/i-hate-my-boost-system-655976/)

AWD-RWD racer 05-25-07 11:03 AM

i hate my boost system
 
ok, ive replaced every single coupler, and every clamp was replaced with t-clamps. now when i hit it, (doesnt matter what gear) it will boost to like 5 psi..then it tries to go higher.....it goes something like this (all within split seconds) 5-6-7-4-5-6-7-5-..........it tries to build boost, but loses it somewhere. any ideas what kinda problem im having. (oh and that boost number is not the seq going on and off....thats just when its trying to build boost)

DriftTrix 05-25-07 11:33 AM

Its kind of hard to get too, but I would make sure that your waistgate actuator bars are hooked onto the waistgate. When the bar is released your waistgate is open, also check the vacuum systems around there for any loose ends because it also needs vacuum in order to open the waistgate.

I had the problem of not going over 5, i dont remember it getting as high as 7 but it may be possible...

AWD-RWD racer 05-25-07 11:55 AM


Originally Posted by DriftTrix (Post 6977198)
Its kind of hard to get too, but I would make sure that your waistgate actuator bars are hooked onto the waistgate. When the bar is released your waistgate is open, also check the vacuum systems around there for any loose ends because it also needs vacuum in order to open the waistgate.

I had the problem of not going over 5, i dont remember it getting as high as 7 but it may be possible...



ill check it out this weekend. but if the vacume lines were messed up (ie the wategate would not be opening) then i wouldnt be losing boost....right? i just redid the whole vac system, a few months ago as well.

gracer7-rx7 05-25-07 12:11 PM


Originally Posted by AWD-RWD racer (Post 6977264)
i just redid the whole vac system, a few months ago as well.


^Did you revisit that instead of randomly replacing couplers?

Sounds like a hose might be incorrectly installed or one of the solenoids is no longer working properly.

AWD-RWD racer 05-25-07 12:25 PM

yeah, but if it was installed incorrectly then why would it work before but not now :) ? may be a selenoid. i dont know. im limited on my time that i can mess with the car. just looking for suggestions on where to start

Speed of light 05-25-07 12:31 PM

I had an exhaust leak from a cover plate on the turbos that caused a similar problem a few years ago. I was going crazy trying to find a problem with the solenoids, etc.. Turns out that 4 bolts loosened up and it was acting like a wastegate. Tightened everything down, and all returned to normal. It's easy to access, but you have to get under the car to a visual check. You can check the TCA and prespool rods at the same time, since they are in the same locaction. So is it making any unusual sounds?

Buzzardsluck 05-25-07 12:41 PM

Ill just assume you havent visited these sites

http://www.autosportracetech.com/RX-...erOverview.htm
http://www.autosportracetech.com/RX-...leshooting.htm

Great pages that helped me out a while back when my seq. system wasnt building boost before 4500rpm.

Another note is that solenoids can check out just fine but still not work, this was my problem.

gracer7-rx7 05-25-07 12:49 PM


Originally Posted by AWD-RWD racer (Post 6977356)
yeah, but if it was installed incorrectly then why would it work before but not now :) ? may be a selenoid. i dont know. im limited on my time that i can mess with the car. just looking for suggestions on where to start


Ah, I see...

Do you run a boost controller or stock boost control?
Does this happen at a certain RPM or throughout the whole rev range?
What are your mods?

I have a similar boost oscillation when I try to run with the boost controller off but its only at transition (~4500 RPM) and only when I try to run less than 10 PSI and only when I run a mid-pipe. If I run a cat, there is enough exhaust restriction that I can properly control boost. I will also be checking what Speed of Light mentioned soon since I never thought of that.

After I replaced vac hoses, I had to go back weeks later as one of them popped off. I wiped it down and zip tied it and its still holding up now.

The links buzzard posted are great reference.

AWD-RWD racer 05-25-07 01:14 PM

mods are:
aem ems
greddy 2row fmic
hks intakes
efini y pipe
3" turbo back no cats
99 spec turbo's
pulley kit
greddy elbow
greddy profec b spec 2 boost controller

as far as sounds...yes....sounds like a high pitched wistle while trying to boost. then when i let off....its like a.......WHEW! noise.

ill check out that under the car stuff tomorrow. maybe something came loose


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