hi i drive a 97 gst which is 100% bone stock so here's the problem, whenever i drive and boost gets up to about 5/8 (between the middle needle and third needle) on the stock boost gauge (omg he doesn't have an aftermarket boost gauge!, working on that :/) it starts cutting out really bad, almost like I'm pressing the gas and letting off repeatedly. so i did a boost leak check and it seems to be holding up pretty much everywhere, didn't see any bubbles at all at 15psi from the air tank except from the 2g bov. so i took the recirculation pipe off and drove it about 1/4 mile just for fun to see if i could hear it leaking and sure enough it leaked extremely bad, whenever the boost gauge read about half way up, the bov actually released completely and the car lost all power, i have a video of it but i cant put it on the computer because i lost the right cable... but anyways i just bought a cone type filter cuz the stock square boxy style are crap and a greddy type s bov to replace the crappy stock plastic one, and now it holds boost but cuts out even worse, i guess because of higher boost but the thing that throws me off is that without the recirculation pipe on the bov it actually runs a lot better. I'm looking for some troubleshooting options :P because i have no idea what the deal is.

also i have a 255 fuel pump, home made boost controller, and an e316g in the garage not on the car so if putting either of those on the car would help with troubleshooting but wont hurt my car let me know

 

You are either overboosting (which you cant even tell cuz you dont have a boost guage), you have a boost leak (check the IC pipes), or your plugs or wires are bad

 

i have checked the ic piping but i will check again and the plugs and wires are pretty much new, only like 15k on them and it might be over boosting i guess i will put on the mbc and set it down about 7 or 8, i forgot to mention that the check engine light is on but its been on for a while because the thermostat sensor or some crap but i ran up to the part store and had it scanned again today to see if another code came up but i couldn't tell because of the check engine light already being on and sure enough there was one, so i got two codes p0170 and p0125, one of them is the thermostat and the other is something else the guy couldn't even tell me. also i read my above post and i wasn't really clear on what was going on so I'm going to try to be more specific. whenever the bov is vented and the hole on the intake is open it runs pretty damn good except a very small cutout, whenever the bov is recirculated there is a large cutout and the car has almost no power, whenever the bov is vented and the hole in the intake is covered, the car hardly runs at all. i am thinking maybe the maf is reading that it is getting more air than what it actually getting because when you add extra air after the maf it runs decent, is this possible?

 

P0170 is your problem. That is a fuel trim malfunction code. Ussually it means that you are not getting enough fuel and probably running lean. That would explain the problems your having. Again it points to me back to overboosting because that will cause a lean condition.

 

what exactly can i do to stop this problem???

 

Did you adjust the boost with your home made boost controller? If you did, you probably adjusted it too high because you don't have a boost gauge to accurately read your boost. Get a boost gauge and see what your boost is set at.

 

p0125 is a closed loop operation temperature not reached ... po125 or mut128 this code is not just a thermostat code if you researched this code any you would know how to repair this code and why it is the problem as to why your vehicle is acting so. any ho this is the break down of this code and how to eliminate it ...

step 1 Remove thermostat check that it closes fully at room temperature .then place thermostat in container of hot water check that thermostat begins to open at 195 degrees F (90.5C)valve lift is .31" from close to open . if thermostat operates as specified go to next step.

step 2 disconnect ECT[engine coolant temperature] sensor connector. check resistance [ohms] .check resistance between ECT terminals . resistance range is 9000-11,000ohms at 77 degrees f . if resistance is specified go to next step if not replace ECT sensor

step 3 Check pcm[power control module ] ECTsensor connector ,junction connector and wiring harness between pcm and ect sensor. if wiring and connectors are fine replace pcm


now i will give you the diagnosis steps for the other dtc 0170 is as stated above is a fuel trim malfunction . and looking at it honestly i doubt you have the scanners involved in tracking this down my suggestion is fix the 0125 and for gods sake this code is as well linked to t he ect sensor so do what i told you here and i bet it will fix your problem . now let me tell you why this is going on and how i know this the first code set the second the ect provides the engine operating temperature. this tells the pcm how to manage the air fuel ratio well untill the car warms up it operates in a closed loop operation and this is read from the ROM[Read Only Memory] in the pcm.after the engine reaches a set temp it switches over in to a open loop state where the ecu can now take sample readings and adjust fuel trim according to the engine demands . now a faulty sensor would not allow the vehicle to get a proper reading so as you step on the gas its not getting all the proper info to make the proper adjustments to the fuel trim in the pcm .so it cannot calculate how much fuel to dump hence the fuel cut.

 

^^^Dude did you not read his post....he knew he had a bad thermostat already. And sorry but i doubt a bad thermo is causing boost cut. But hey you never know.

 

ill try it out asap, and ya i dont have the stuff to check but i have a friend who does and ill be going over to his house as soon as he is off work, is it going to kill my car to drive it as is until then??? itll probably only be a few days

 

Just dont floor it and try to stay out of boost.