HeatTreated

On going problem of unreliable boost pattern. (profec b acting up I think)
But when it does work, I hit 10psi, transition comes on and it bounces from 12psi-8psi several times and finally catches 10psi at about 6k rpms. What causes this?

HeatTreated

No one ever had bouncy boost huh?
Probably just a bad Profec B Solenoid Box... anyone have that?
Im going to trade out with forum member Mikey and see what happens, if so I hope Greddy takes care of it.

bureau_c

It sounds like your sensitivity (I'm not 100% sure they use that word...sharpness maybe? Attack?) adjustment is off. Try turning it down. The way I understand it, turning it higher causes your boost to ramp up faster, but too high will make it more unstable, causing spikes or at worst, oscillation like you're seeing. Turning it down too far causes ramp-up to full boost to take overly long.

Did the Profec-B work fine, and then suddenly started bouncing one day? If you so, check that the **** in question hasn't inadvertantly been moved. If not, maybe the box does have a problem.

jds

FtWorthless

I have this exact same problem! You're the first I've heard other than me with it. Mine bounces between 6-10 psi though, and then settles at 10 psi around 6K like yours. It is a new problem since my complete vacuum hose job, and is intermittent. My car is completely stock except for an Efini Y-Pipe and some extra ground wires, so it's not related to any boost controller issue, at least not for me. The problem must be related to the TCA. My TCA does not cycle with key-on key-off as it should, so I think it must not be getting vacuum or pressure properly from the solenoids. I haven't diagnosed beyond that though.

HeatTreated

thats interesting because Ive narrowed mine down to a bad Profec B control box.
like you Im still investigating.
Ill check the TCA. thanks.
I forgot to mention, at times I get a perfect boost pattern. but rarely anymore.