Gtr Runs Like A Dog With Boost At Low Rpm

[glasstechaudio]

hello everyone, i used the search but couldn't find anything that solved my problem. i have an 89 GTR and occasionally, although it seems to be happening more and more often, when i start up the car when given the smallest amount of throttle it gets a minimum of "0" on the boost gauge. (i have an aftermarket greddy boost gauge that the last owner spliced into the fuel pressure reg. line) it won't go negative if i have my foot even slightly on the gas. also, it spools up very quickly, it'll be around .5 bar by 3k rpm. when it does this it runs like a dog until it get to around 3500 rpm, at which point it takes off like normal. there is a deffinate power increase at 3500 rpm but the boost gauge doesn't go up, in fact it usually twitches to lower boost. also the exhaust temp goes way up fast. after a few km it, very noticeably, goes back to normal. it will run normal boost pressure and not be sluggish at all. also when it is doing this if you try to just drive it normally and maintain a speed it will sputter and cut out, the boost gauge also twitches when it sputters. it feels like the car is breathing through a straw, or has a potato in the exhaust or an air / fuel problem. it doesn't do it all the time and i am totally stumped on the source of the problem.

also the previous owner had butchered the factory wastegate and bov vacuum lines. they removed the factory boost control solenoid and install dual hks bov, then ran the wastegate lines to the bov's. currently i have the wastegates hooked up correctly and the bov's with no vacuum lines going to them at all, when i tried hooking a vacuum line from the plenum to the bov's it kept bleeding boost pressure.

any ideas??? i need some good pointers or at least a "start looking here" from someone. thankyou for reading this and any help you can give.

[GeeTR]

Sounds like a disaster; BOV feeds, wastegate feeds and boost gauges tee'd into FPR feeds.

Start at the basics.

- If the factory solenoid has been removed, what controls boost?

- Your aftermarket BOV will need a vac source so it seals. Either hook it up properly or remove it.

- Remove ur boost gauge from the FPR feed, and hook it up somewhere else (stock MAP sender?)

- Your inlet plenum seeing less vacuum when you race the motor is normal lol

- How long have you had the car, do the issues coincide with you doing anything to the car?

Get a workshop manual and good luck