Guest jjohart Posted December 22, 2003 Share Posted December 22, 2003 Hi, my Z mechanic spent several hours hooking up my Greddy Profec B and then used a pressure gauge to street test it, and found it wasn't regulating boost at all, it was heading into 15psi range, where my modified blow off valve would kick in, both in "low and high" boost settings. He took a pressure pump and gauge, and told me it was a defective unit, that it should have been regulating the pressure. Funny thing is, on the drive to the manufacturer approved dealer to send it in today, I found it was affecting the amount of boost-to some extent-BUT IN REVERSE...turning the low or high boost knobs all the way clockwise (to what you'd think would be max boost) caused the boost pressure to be starkly limited. Turning the dial counter clockwise, say, 3 o clock or less, the boost gauge indicated higher boost when I did up the throttle pedal. I am still concerned it isn't regulating such boost properly, as I still think I'm going up to the pop off valve's point of release, as in a secondary woosh. What else can I check? Could the mechanic have reversed something in the wiring harness? I have already tried reversing the solenoid "in and out" hoses, and that made the unit totally restrict boost, not even much into red with the stock 280ZXT gauge... I don't know whether to send this in, and so far, Greddy tech support isn't being very helpful. Anyone know this unit like the back of their hand, as to what's going on? This is the older unit with three dials. I can't understand why an LED is always on for selecting low or high boost...I thought these were two ranges that worked together? Help? happy holidays John Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 22, 2003 Share Posted December 22, 2003 do not even pay attention to the stock ZXT boost gauge... everyone pretty much agrees that they are grossly inaccurate and therefore useless. If you are going to be doing ANY boost adjusting you really need an aftermarket gauge, and the autometer ones will fit right in the stock gauges spot nicely. Good thing you have some kind of pop off valve on there otherwise you'd be seriously risking engine damage running a boost controller that is obviously not functioning properly. While youre engine may be safe, you still may be overspinning and potentially shortening the life of the turbo itself. Quote Link to comment Share on other sites More sharing options...
J Taylor Posted December 22, 2003 Share Posted December 22, 2003 I haven't messed with a profec in a while but it seems like there are 2 vacuum ports on the sensor part of it. I never could get my profec to work right for whatever reason but seems like at one point I had the 2 vacuum lines reversed and the boost went nuts to well over 20 psi before I could get out of it. Make sure the 2 lines aren't reversed. I believe one goes to the wastegate and the other to the manifold. One other thing you may want to check is the switches on the back of the control box that tell it what kind of wastegate you have (internal or external.....there are 2 settings for each). If you don't have directions I think you can find them at http://www.mkiv.com Good luck. JT Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted December 22, 2003 Share Posted December 22, 2003 I have a turbo timer which also displays boost, but in KG, so I kinda have to convert. Basically, it is telling me I am boosting between .93 and 1.0, so my guess is the boost control is pushing anywhere from 13.5-15.4psi, which is why I keep hearing the blow off valve if I press the throttle hard on enough! I guess I should pull this unit off and send it away! John Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 22, 2003 Share Posted December 22, 2003 J Taylor is right. Check your plumbing, to make sure you haven't switched the boost line (to compressor housing and wastegate) with the MAP line (to the manifold). And there are two modes, internal wastegate and external - the logic in controlling these is probably different, and switching modes could result in what you are seeing. I wouldn't try to send it back until you have a good grasp of how it is installed. My unit works perfectly, the low boost mode will regulate right at 12 psi, for the tight road courses, and the high boost regulates at 16 psi for the street and strip. Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted December 22, 2003 Share Posted December 22, 2003 I already tried reversing the hoses at the solenoid..no effect, in fact not even making max. factory boost level. I think it is properly hooked up, but the switches on the back of the unit have to be re-adjusted. DOES ANYONE ON THIS SITE KNOW WHICH FOUR PIN/UP-DOWN SETTING IS CORRECT? I mean, even my experienced Z mechanic set it for external wastegate b/c he saw a metal rod to it, but then the Greddy tech asked me if there's a nipple coming off the turbo, or something about the header having a supply line..I get so confused. All I know is, the boost controller is working BACKWARDS..Sulu, that's impossible!!...there's gotta be a hard fast rule on the right switch positioning, and now even my mechanic and the Greddy tech are saying reverse the switches...SO, IS an 83 280ZXT an external wastegate, or internal set up, so say youse guys?!?!!?? Quote Link to comment Share on other sites More sharing options...
jp 280 Posted December 23, 2003 Share Posted December 23, 2003 standard has only an internal waste gate Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted December 23, 2003 Share Posted December 23, 2003 Theres only a couple of wires on them so I would think that it is wired wrong just maybe set wrong. Check the manuel for how the switches in the back are to be set and make sure the hoses are routed correctly. One goes tot he wastegate and the onther to the vacum/boost signal line from the manifold. Set the first knob to the middle postion to start with then you could tune from there. These are very easy to use and should work good for you. Quote Link to comment Share on other sites More sharing options...
J Taylor Posted December 23, 2003 Share Posted December 23, 2003 John: Look at this pic. If it doesn't work go to the link. This is part of the profec b instructions from the website I linked you to above. This is the page that tells you how to set the switches on the back for the type of wastegate you have. Make sure yours are set like the far left or the 2nd from the left. Try them both and see if it helps anything. The right 2 are for external wastegate so I wouldn't worry about them. If this doesn't work go to this website and look at the whole instructions and make sure yours install matches. Hope this helps. JT http://www.mkiv.com/techarticles/greddy_profec_b/08.jpg Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted December 23, 2003 Share Posted December 23, 2003 Yes, the thing works properly when switched for internally activated wastegate! The external wastegate settings were my mechanic's fault! Should I ask him for a refund for the hour he spent trying to tell me it's defective instead of knowing that?!!? Thanks John Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted December 24, 2003 Share Posted December 24, 2003 If you have it set for an internal wastegate and you're still overshooting your boost, flip the switches in the diagram as shown for the other internal wastegate setting for overshoot problems. I have a Profec B on my Z and it works perfectly fine. Have you tried messing with the Mild/Sharp knob along with your boost setting? If you have an open stretch of road where you can hit between 50-90mph without causing harm to anyone but yourself, then you'll be able to set the Profec B. Make sure you have an accurate boost gauge though. It could help to have a passenger due the setting while you drive. John 82ZXT Quote Link to comment Share on other sites More sharing options...
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