WaLieN, you can't use a bleeder on that, since it will constantly bleed the pressure out of your tank when then car is under vacuum (which you don't want to happen).

The grainger valve is more of a "pop-off" valve, it only vents at the set pressure. The further you screw it in, the more pressure it takes for it to vent. When the pressure drops below the set level, it stops venting.

I get mine from McMaster-Carr (www.mcmaster.com).

From them, the valve is part number 48935K25, but you may need to unscrew it and put the ball on the other side of the spring in order to convert it from vacuum to pressure blow off operation.

The hose barb (3/16") for it is 5346K51

Well, per TCB100's suggestion, I tried switching the lines to the actuator... no love. Normal boost , with no transition and tapering off above 4500.

Occasionally, my car will make the farty-no-power-didn't-transition-back sound when I haven't "boosted" in a while, say after i've sat at a light and try to pull away quickly. That was definately gone with the hose switch.

I guess i'll have to try the bleed valve.

Be so advised that the same TC solenoid that AUTOXER has had difficulty with also has shown a partial failure mode. I discovered this during testing about a year ago, while chasing another problem. I'll leave it up to you to consider the ramifications this could have.

Here's what happens: there is pressure on the TC solenoid, it switches states and should vent. It does not, rather; it will bleed down slowly, in my case it took 30 seconds or so from 15#, and when it got down to about 3 psi in the line then the internal spring would overcome the pressure and it would open rapidy. Found a spare, it worked fine.

AUTOXER: Great job on the methodical troubleshooting.

I was reading his post with great interest because I occasionally experience a similar problem. However, in my case, boost always comes right back to about 6 or 7# and sits there (when the seconday should be fully on-line). It's acts like the secondary is locked out--just as when the engine is cold. This could have something to do with the wastegate controls. Further testing is indicated, but I'll take suggestions...

FWIW: I have also diagnosed another unsual boost transistion & secondary behavior to a leaking cover plate over the precontrol valve on the turbos. IF YOU HEAR A BUZZING, RATTLING OR RAPID METALLIC TAPPING SOUND THAT STARTS AND GETS LOUDER AS PRIMARY BOOST IS DEVELOPED then check this cover on the turbo center section for leaks. I wrote a post about this problem for another thread. For more info. search on my name to find it.

The pressure relief valve didn't work. The solenoid spring must be weaker than 9 psi. I guess I need a new solenoid.

Pressure Chamber Regulator
 

I use the Norgren R07-100-RGAA which can be purchased: http://www.jhf.com/CatalogHtml/0676.htm
It should be place between the check valve and the pressure chamber. It comes with a guage, so you can read how much psi is being stored in the chamber.

Back from the dead:

I've located a presure regulating valve (Peter Farrell actually put it on my car years ago to help w/ this problem, and it was subsequently removed by KD when the motor was done), however, I would think it would be better to plumb in AFTER the presure tank, instead of before... that way the tank can hold all it wants, but you know that the "feed" to the solonoids will only be X amount. I suppose it's real easy to try both ways though.

Any disadvantage to plumbing after the pres. tank?

What sort of valve are you referrring too?

If you are taking about the check valve then it needs to be before the tank Sounds like you are saying PFS added a non-stock valve.

I've had the described problem in this thread since installing the PFS puple 'puter WAAYY back in '98-99. I initially took it to PFS, who had it for a couple weeks, and returned it declared "fixed". Worked better, but not exactly perfect. That fix included this non-stock pressure regulating valve, clearly visable near the pressure tank, though I can't remember exactly where.

The car went to KD rotary in '01 for a new motor, and Dave removed it in addition to other little things. Still never really worked right. I put in '99 turbos last spring, and it worked perfectly when I got it back, for about three weeks... when I took the car back to RP for a re-try on the oil pan reseal. Got it back, and it didn't work well at all.

I took it apart, replaced the TC solonoid with a brand new one, and replaced all of the silicon lines going to it. Checked the pressure and vac tanks, and replaced check valves. Still doesn't work. I currently run the car with the pressure line to the actuator disconnected completely, and it runs passibly OK on vacuum alone. That's how i know it's pressure-related. The pressure obviously isn't being vented imediately when the throttle is released, and hence the solonoid is stuck in twin mode.

I found the old valve in the box of stuff i got back from KD, and I'm going to try it again.

BTW: here are some photos showing doing a test while the solenoid is still in the rat's nest and in the car.

:-) neil

PS: note the power-supply made by me from 1980!

http://www.silcom.com/~neilv/rx7/diag-setup.JPG
http://www.silcom.com/~neilv/rx7/12vdc.JPG
http://www.silcom.com/~neilv/rx7/T-tap-n-mityvac.JPG

Oooohhhh..... you should really consider stuffing rags or something in your LIM ports to avoid dropping something in them. :eek:

Yep, I stuffed them with rags after I looked at this picture.

:-) neil

I dug up the regulator PFS stuck on my car back in the day, and as soon as I locate a mityvac to test/reset the pressure level to about 9-10 psi, i'll try it and report. Stupid me, I futzed with it and moved the setting... otherwise I could've just thrown it on.

UPDATE:

Problem solved!!
I connected a mityvac and boost guage to the air presure regulator, and set it for 9 psi max. I read in the manual that the actuator itself is meant to work with between 7.5 and 11.5 psi... and i'm guessing the solonoids were as well. Spliced it into the outgoing presure line from the pressure tank, and viola! No more boost issue, even running 15 psi.

I wish i'd put this thing back on years ago! One of the PFS mechanics obviously analyzed what was happpening a long time ago. I can't believe how much time and money i wasted to get back to this point.

Not quite sure what you did. Could you post a few pics to help me visualize what you are talking about?

Dave et al.,

Can someone verify that the Turbo Control solenoid is the THIRD one from the front ?

That is, it is the solenoid with the Tan electrical connector ?

Which one is the charge control solenoid ?

I'm asking, because my symptom is back . . .

:-( neil

Yes, it's the third one from the front on the bottom - dig up the vac diagram and follow the lines to the turbo control actuator to be certain.

Dave

I'm having some boost issues that might be a result of my bad knock sensor trying to kill HP.

I'm surprise that no one has mentioned this.