Alex

In trying to find my boost problem, I noticed something interesting about the Turbo Control circuit. My car is generating pressure on one side and vacuum on the other, but it will not release until both the rpms have dropped below 4500 AND the clutch is pressed. In other words, if I'm autocrossing and slow for a corner (down to say 3000rpm), but don't downshift, then get back on the power, the turbo control will still be open, causing a slow build-up of boost. If I were to dip the clutch just before I get back on the gas, the turbo control would release, and I would build boost much faster coming out of the turn.
My car is totally stock, so is this a problem with my car, or is this normal? Anybody ever noticed this?

CCarlisi

I have a similar problem (which I'm sure everybody is sick of hearing about by now). When I gun it from 2k-8k everything is fine, but when I let off so the revs drop below 4500 but stay above 2800 I get little to no boost. From here I can do 1 of 2 things: (1) let revs fall to 2800 at which point, according to the PFC commander, it switches back to primary only mode and I get power again (2) wait for the revs to climb back to 4000 and then power builds normally.

when you let out the clutch are the revs falling to 2800? -that might be what's doing it not the clutch.

Here is what I've replaced so far:
all vacuum lines
all check valves
checked pressure and vac tanks
both turbo control solenoids(1 on the manifold 1 on the rack).

nothing has helped. Dave at KD said it might be a short in the wiring harness(dear god) but hasn't tested it yet. I know two other people that had this problem. One was in alaska and I'm not sure what happened to him. The other blew his motor due to other issues.

Not sure if this helps, but I try:p

cool_koo

I'm getting the same problems... mine can't make boost unless I slowly thottle the gas...

Jared_rx7

I have the same problem as you guys and it's such a bitch when you wind it up in first gear and then go to catch second at about 3 or 4 grand and you get almost no boost at all. The boost will gradually build up after 4500 but if I where to just gun it in second at say 2500 then I would get a perfect boost pattern. It just doesn't make sense, any help would be appreciated.

Alex

Sounds like you're describing the same symptoms. Here are a couple scenarios I tested.
1. Floor in 2nd from 2500rpm, turbo control opens at 4500. Shift to third near redline, turbo control stays open. Let off to about 20% throttle in 3rd, hold for 5-10 seconds (still above 4500), then shift to 4th. Turbo control switches off the instant I hit the clutch, even before the revs drop. Repeated this 2 or 3 times.
2. Floor in second from 2500 to redline. Then slowly slow down to about 3000, still in 2nd. Push clutch in and hold, turbo control turns off.

My boost problems all started when I changed the vacuum hoses, so I'm assuming it is not an electrical problem.
Can anyone confirm or deny the relationship between the clutch pedal switch and the turbo control solenoid?

Alex

By the way, this isn't my original problem. I started taping into the systems because my boost pattern is 10-5-8. I thought I wasn't getting either pressure or vacuum on one side of the turbo control, but obviously I am, so I must have some other problem, I'm next going to check out the pre-control circuit.

CCarlisi

awhile back someone told me this was normal. the theory being it is more efficient to let it lag if it's just below the transition point than to switch it back to primary only mode for a second then back to primary/secondary mode. I can understand that if it didn't switch at say 3500 but 2800 seems pretty low. It's cutting out 1700rpms of power in the middle of the powerband.

BTW on the PFC switch menu you can monitor the function of the solenoids that control both actuators associated with the seq non seq mode (believe the turbo control actuator and charge control actuator). When it gets stuck in non seq mode both solenoids remain in the non seq mode. So whatever the cause is must be effecting the signal that they get.