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Overboost only with boost controller solenoid


Sam280Z

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I'm at a loss on this one.

I have a PRofec Bspec boost controller.This one

If I run the wastegate hose straight from the manifold to the WG, I get 10psi boost before the WG opens.

If I hook up the solenoid box - run the hose from the manifold to the inlet on the solenoid box and then a hose from the solenoid box outlet to the WG, I get 20psi with the boost controller off. I can blow straight through the solenoid box. I even applied 10psi of compressed air and it seems to go straight through (although there seems to be a little restriction).

 

This unit was working before I rebuilt the engine. While installing it, I did drop the solenoid box - but I opened it up and can see no damage - looks to be pretty robust.

 

Anyone have any ideas on what might be going on?

 

Sam

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Did you try adjusting the dip switches on the back of the boost controller? I know you said it worked before, but there are adjustments you can make if it's overboosting. I figure it's worth a shot. Did you check to make sure your reference line to the back of the controller is hooked up? Also, are you running an internal or external wastegate? If it turns out that the profec is broken, I have a used one for sale in my parts for sale ad

My link

 

I know, it's a shameless plug, but I really do hope you can get yours working. I really liked mine when I had it on my car.

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Is it internal or external W/g? Did you try disconnecting solenoid wires and run?(not just unit off, but solenoid box wire completely disconnected)

If you have it hooked up like external W/g with two hose, blowing through is going raise boost.

 

Just curiosity, how is the tune with ITB turbo? Are you using MAF? What ECU? how is part throttle run? ITB turbo usually needs advance tune...

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Its a Tial external WG. I have not tried disconnecting the wires. Will try that this evening.

 

I don't understand what you mean by "If you have it hooked up like external W/g with two hose, blowing through is going raise boost."

I thought that having it hooked up Manifold -hose-> Solenoid -hose-> Waste Gate would make it act as if there was nothing there if the controller was off. It boosts perfectly to 10lbs if I bypass the solenoid.

 

I'm still working on the tune. Using Megasquirt running MSnS-Extra High Res.

It drives better and better each day as I learn. I just got it running again after a complete rebuild. I bought this car last year:

Car Ad

 

In October, a over-rev caused by stuck accelerator broke a ringland on the #5 piston. I fell into another "while I'm at it" trap...

 

N47 Block with JE pistons (flat top w/ valve reliefs) from Rebello Racing.

P90A head converted to solid lifter. Rebello port & polish. SS Valves. Rebello Cam.

Fidanza Flywheel (Spec friction surface) Spec clutch.

TWM throttle bodies, TWM manifold, Cartech plenum.

Siemens Deka 63lb injectors

BHJ Harmonic Balancer

Stock exhaust manifold w/ Holset HY35W turbo

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If disconnecting solenoid works,that means dip switch is set on external W/g.

External W/G has two ports, top and bottom. You are probably using only bottom port.

So, boost controller has dip switch to change from internal W/G to external W/g. You are using external W/G like internal, which is ok but boost controller dip switch should be set to internal W/G.

Maybe you had it hosed like external W/g before rebuild?

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Xska, you da man.

It was the dip switch. It was set to internal originally. When I rewired everything, I noticed this and switched it to external since it is an external WG. I switched it back to internal and it is working again. Thanks!

Sam

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Xska, you da man.

It was the dip switch. It was set to internal originally. When I rewired everything, I noticed this and switched it to external since it is an external WG. I switched it back to internal and it is working again. Thanks!

Sam

Do itashimashite。

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