| Please let me know if im on the right track. My 300zx is currently running 6PSI. Before this it was boosting at 4PSI! Car remarkably was running pretty smoothly at 4PSI i did not notice with daily driving not boosting very much for a long time until i put it on the dyno. After doing some boost leak testing found some big leaks in the turbo piping and had them tightened up. Except after all that tightening i gained 2 pounds of boost to get my current max boost level of 6PSI. The wastegate actuator suppose to open at about 7PSI max and from my understanding the boost solenoid when open is basically acting like a boost jet when its open tricking the system to run 3PSI more (about 10PSI). If the boost solenoid is closed (boost safety) we only get about a max of 7PSI governed by the wastegate actuator. Therefore if the car is in that PSI range (6-7) it should be in safety boost mode as the boost solenoid should be bleeding about 3 pounds from that T-joint we were looking at today. I also read that during a boost leak test or similar (ie smoke test) sometimes you'd get oil squirt out of the cam seals (or smoke) just indicates that they need replacing. There isnt a correlation with boost there because you are not suppose to see boost pressure in the valve and crankcase but during a boost leak test you are going to see pressure there since it is pressuring the system starting from the AFM which is not under boost pressure. At first i thought i might have lost 1lb of boost pressure from that but i dont think so now. I believe the auto turbos are rated lower boost pressure not sure if that has to do with the slightly smaller turbos (a fact). I found some good diagrams here:
 heres an actual picture of the solenoid:
 This article here I found really informative:
[ http://www.thumper300zx.com/z32/factory_jets/factory_jets.htm ] What I find strange is that the ECU is not throwing codes! not exactly sure whats going on here. The ECU is the one that is sending the signal to the solenoid right so if the solenoid is malfunctioning it should throw a code. Hmm if the engine is cold the solenoid is engaged from the ecu by default i believe but when we put it on the dyno it should have been pretty warm! If the ECU detects knock from the knock sensor for example it sends 12V to the solenoid to close it. Which should give a code 34 for knock sensor. Also it should detect overheating too. Perhaps the electrical connection is bad or the solenoid is somehow seized. I am leaning towards that this is a boost solenoid issue but not 100% sure. Let me know what you think. THANKS FOR READING
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300zx low boost issue - 
