83turbo280zx Posted February 10, 2009 Share Posted February 10, 2009 hey guys, i have an 83 turbo 280zx with a WEIRD problem. I have a boost leak that i have never seen before, here's the scenario Im @ WOT in 1st gear, my gauge shows my boost levels spiking between 7-10psi rapidly, and also a loud hiss can be heard from under the hood in synch with the boost spike to 10psi. I shift into second gear same thing, and as soon as i shift into 3rd gear it spikes to 10psi once, and then hits a steady 7psi with a loud hiss. I have a NSX Manual boost controller made of basically home depot parts, bought the whole thing on ebay, i checked the bleeder hole which was free of any dirt or clogs, checked all of my wastegate lines, good, checked all vacuum lines, good. Reseated my jpipe couplers, also replaced the line from the Jpipe going into the vacuum control valve, aac valve, etc. There was a tear in that line so i replaced it, tightened all clamps, still have this spiking problem. I am lost as to where to start next. I dont think its my Emergency Relief Valve because i put washers in it awhile back to keep it from opening under 10psi. Here's when it started happening. The other night i was on a cruise driving around with a bunch of imports in the area when i started running only 5 cylinders, i pulled over and checked my wires, #6 came undone, so i re-seated it and everything was fine. Then on the way home i was reaching full boost no problem, 10psi every WOT pull. Then out of nowhere in one of my WOT pulls getting on the freeway i hear a loud hiss and it shoots down to 7psi. And ever since its been doing this sort of problem. I can give it 3/4 throttle and it will creep to about 9psi, but as soon as i go WOT it will shoot down to 7 and start hissing @ me. Anybody have any clue? I've tried searching all around for common problems with the VCV and AAC valve and haven't seen anything like what i have. If i haven't given as much info as you need, please ask and i'll answer any questions that you have that can help you help me out. Any ideas? Quote Link to comment Share on other sites More sharing options...
z-ya Posted February 11, 2009 Share Posted February 11, 2009 How does it behave without the boost controller removed? Does the boost go to 7psi and stay there? If so, your Home Depot boost controller is probably suspect. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted February 11, 2009 Share Posted February 11, 2009 Do you have the factory turbo intake manifold on the car? and If so have you modified the factory pop off valve? it is set to open at 10psi so you will not over boost your car. Quote Link to comment Share on other sites More sharing options...
83turbo280zx Posted February 11, 2009 Author Share Posted February 11, 2009 Do you have the factory turbo intake manifold on the car? and If so have you modified the factory pop off valve? it is set to open at 10psi so you will not over boost your car. not to be a douche, but i said i put washers in it in my post, lol. anyways i've solved the problem, tonyd pointed me back to the pop off valve and it was indeed the culprit. it was on its way out i can open it with my fingers and after i put the washers on awhile back that was very hard to do. thanks for the input tho. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted February 12, 2009 Share Posted February 12, 2009 Yeah sorry about that I missed that line. But yeah even after putting washers on it after a while the spring can weaken and I suspect that's what happened. You can go to Lowes and get the correct size pipe plug and just plug it. Quote Link to comment Share on other sites More sharing options...
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