Intermittent multiple cylinder misfire helpppppp!!!!

[Calcam22]

I just recently purchased a 199 gst and this is my first turbo vehicle. I've had it for a few days now and I already am getting massive migranes . When I purchased the vehicle it had a p0300, p1400 and 4 other codes I can't remember at the moment I will add when I find where I wrote them down at . The rmcm is intermittent, it will run good for a little but when you start crusing it starts acting up like loss of power and sounds like a Sti kind of and after it does it the first time every couple minutes it goes into that "mode". I have checked and cleaned almost everything I can think of that would cause the problem but no success. The maf is good. The plugs and wires are good and the coil is good. I don't have and boost leaks anywhere and the motor has great compression. It does have an eBay fpr(the gold one with the gauge on top don't know the brand) and I think an aftermarket bov. Stock wg. Now the way the previous owner uped the boost was creating an open leak off the wg. Vacuum line comes off wg to a T one side is open and the other goes to the intake manifold. The vacuum line from the bov is stumping me. There are two nipples on it one on the top and one on the bottom. I have it connected to the top one because it releases pressure the best. Now that line goes to a T as well then from there to the boost gauge and the other side goes to yet another T. This T one goes to the intake and the other goes to my fpr. Back to the bov if I have the line connected to the bottom it only puts out 7 psi but if I have it at the top it makes 20 which is way to much I think. I'm just a true newb to the whole turbo world and need some serious help

 

[dsmer1]

I just recently purchased a 199 gst and this is my first turbo vehicle. I've had it for a few days now and I already am getting massive migranes . When I purchased the vehicle it had a p0300, p1400 and 4 other codes I can't remember at the moment I will add when I find where I wrote them down at . The rmcm is intermittent, it will run good for a little but when you start crusing it starts acting up like loss of power and sounds like a Sti kind of and after it does it the first time every couple minutes it goes into that "mode". I have checked and cleaned almost everything I can think of that would cause the problem but no success. The maf is good. The plugs and wires are good and the coil is good. I don't have and boost leaks anywhere and the motor has great compression. It does have an eBay fpr(the gold one with the gauge on top don't know the brand) and I think an aftermarket bov. Stock wg. Now the way the previous owner uped the boost was creating an open leak off the wg. Vacuum line comes off wg to a T one side is open and the other goes to the intake manifold. The vacuum line from the bov is stumping me. There are two nipples on it one on the top and one on the bottom. I have it connected to the top one because it releases pressure the best. Now that line goes to a T as well then from there to the boost gauge and the other side goes to yet another T. This T one goes to the intake and the other goes to my fpr. Back to the bov if I have the line connected to the bottom it only puts out 7 psi but if I have it at the top it makes 20 which is way to much I think. I'm just a true newb to the whole turbo world and need some serious help

have you pulled your plugs, read them, and regap them? that could be the cause of the
misfire. have you performed a BLT? and a diagrame or even pic of these multiple t peices would be a great help

 

[Calcam22]

I replaced the plugs the day I baught the car with ngk bpr6es plugs. Please explain what Blt means like I said I'm new to all this. And I would show pictures if my phone would let me upload them but since I'm doing this from my phone I can't I'm still trying tho

 

[dsmer1]

yes you may ahve bought the plugs, but they might not be gapped correctly. the gap is .028" and a blt is a boost leak test. it tests all leaks in the intake and hoses that see vacuum.

heres the link: http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html

and i diagram at least would be great. its hart to follow all of the t pieces and where they go. but it sounds rigged. this is why that diagram would be a great helper

 

[delta448]

Vacuum line comes off wg to a T one side is open and the other goes to the intake manifold.

Unless there is a bleed-off restricting device in the T itself or right after it on the open port, this setup disables the wastegate. The wastegate actuator must see boost pressure to open the wastegate, if the vac line to it is open to atmosphere, no pressure is getting to the WGA. To fix this problem, plumb the WGA directly to a nipple either on the compressor cover or on the intercooler piping as close to the compressor discharge as possible. Plumbing the WGA to the intake manifold is not recommended as it disables WG function during rapid throttle close and can cause overspeed when the BOV opens under intake manifold vacuum.

Back to the bov if I have the line connected to the bottom it only puts out 7 psi but if I have it at the top it makes 20 which is way to much I think.

It makes 20+ on the top nipple because the wastegate is not functioning properly and ~7 on the bottom because when you connect your line there and leave the top unhooked, there is no pressure on the top of the diaphragm holding the valve closed. The top nipple should be connected to the intake manifold on a dedicated line, the bottom nipple should be connected to the charge piping on a dedicated line. -Assuming you have a typical BOV and want to use the "fast release mode", otherwise just cap off the bottom nipple and the valve will hold without leaking at higher boost pressures.