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Discussion Starter #1
I have a Profec B installed on my 97 supra. I was running 1.3 bar on the low boost setting. For the last couple of days I have been unable to boost past 1.1 bar. I turned up the knob almost all the way little by little and still nothing past 1.1 bar.

The clincher is that the boost controller works fine on the high boost setting and I am able to boost to whatever I set it too.

This would rule out boost leaks, vacuum leaks, and stuck solanoids since all these would be shared on the high boost setting. Someone suggested a defective head unit.

Has anyone ever experienced this problem? If so is there an easy fix for it?

Any help would be appreciated. I am ready to pull the head unit and send it back to greddy if I can't figure this out.

Thanks,
Pete
 

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Magic said:
I have a Profec B installed on my 97 supra. I was running 1.3 bar on the low boost setting. For the last couple of days I have been unable to boost past 1.1 bar. I turned up the knob almost all the way little by little and still nothing past 1.1 bar.

The clincher is that the boost controller works fine on the high boost setting and I am able to boost to whatever I set it too.

This would rule out boost leaks, vacuum leaks, and stuck solanoids since all these would be shared on the high boost setting. Someone suggested a defective head unit.

Has anyone ever experienced this problem? If so is there an easy fix for it?

Any help would be appreciated. I am ready to pull the head unit and send it back to greddy if I can't figure this out.

Thanks,

nah nothing wrong with it
mine does that too
at low boost at max level cant pass 1.1
and high boost whatever u want
i never set at low boost , doesnt even feel like my car's fast
i always set mine at high boost around 17psi
usually i turned it off if not racing :)

Pete
 

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Mine only hit around 22 psi.... I swapped it out with an EVC EZ.

Profecs have a reputation of doing this type of thing.
 

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Discussion Starter #5
Josh S said:
I can only hit 1.2bar with the low boost all the way up. The high boost knob let's me go as high as I want to.
That is strange. I was able to hit a solid 1.35 bar with the low boost knob at just past the 12 o'clock setting before.

Does anyone have any idea why this would stop working all of a sudden?

Thanks,
Pete
 

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i am having the same type of problem. i can't adjust the low boost setting at all on mine. its always at 8 psi and doesn't go any higher or lower. i hate these damn things. the high boost setting works fine but i can only boost to 18 psi on cold nights and around 15 or 16 psi in the summer. i think a lot of it has to do with my altitude. i live in colorado which is around 4300 ft.
 

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I can tell you that so far I think the Greddy Profec B is a complete piece of crap...but I'm willing to bet that the installation is also crap, so I can't blame the boost controller just yet. Once I have my mechanic investigate more thoroughly, I'll have more to say on the matter.

I am personally a big fan of the HKS EVC EZ, and by default I will be swapping over to that in the future. ;)

Steve T.
 

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Ask Lar at SP. 630-893-5002

He has done many PROPER twin-turbo/Profec B installs. It is a bit tricky. I'm pretty sure it has to do with the MKIV setup only, as I have installed/programmed many 300ZXTT's and DSM's with no trouble with either the low or high boost settings...
 

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Discussion Starter #9
FYRARMS said:
Ask Lar at SP. 630-893-5002

He has done many PROPER twin-turbo/Profec B installs. It is a bit tricky. I'm pretty sure it has to do with the MKIV setup only, as I have installed/programmed many 300ZXTT's and DSM's with no trouble with either the low or high boost settings...
How could it be installation, if it was working properly for a week and all of a sudden just stopped working? I doubt it could be a problem with the installation since it worked fine before.

Also remember high boost works fine. Any other suggestions/comments would be appreciated.

Thanks -pete
 

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I have the Profec-B also and I had Phil Panas install mine and I know for sure it is not the installation, its the head unit for sure. I can set my low boost to around 16psi, and when I get on it the damn thing creeps way up to 22psi on a good cool night in ATL. So I set the high boost right to around 18 psi and I only hit around 16-17 psi that's it. My high boost does not work properly at all. I seem to overboost on low boost settings periodically. I thought I had the system figured out about two weeks ago when I uninstalled and reinstalled the ProFecB. Everything worked great for about two weeks, then just this past Saturday when racing a SC 01 Cobra, I got on it at boost setting at 18, the damn thing shot way up to 23psi. So I strongly believe it is a problem with the unit not agreeing with the supras.
 

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Discussion Starter #11
does anyone else have any input on this?

thanks,
-pete
 
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