2G BLT Air Coming From Valve Cover Breather Hose

[JeffwithaG]

Hi everyone, I am attempting to determine why my GSX Bucks/Hesitates when going WOT. I can gradually build boost all day long without an issue, but if I floor it, it falls flat on its face. It bucks, pops, hesitates, etc. I have the same issue when swapping Mass Airflow Sensors and I dont have any CEL's.

Anyway, I am troubleshooting the issue with a BLT. I fixed a small leak at the BOV flange, but now there is air coming out of the hose from the Valve Cover that routes back to the air intake. I swapped out PCV's; I have a genuine Mitsubishi one on now, I also verified its working appropriately and I get the same result. I also get the same result when doing the BLT with the engine cold or warm.

I'm not sure if this means turbo shaft seals are bad? Or something else. The car doesnt smoke and it idles nicely.

I've attached a picture. Its coming from the hose resting on the BOV. I'm sure you all know this as you are all smart as hell and well versed with these cars. I'm just trying to fumble my way through this.

I'm leaning towards the knock sensor or the TPS being incorrectly adjusted. I went through the procedure of adjusting TPS when I installed the rebuilt throttle body. I dont have a pocket logger or DSM link.

I'm really stumped. Anyone in New Jersey want to work on this car haha? I just want to be able to drive it once with full power and enjoy the DSM awesomeness.

Maintenance Includes:

New NGK Plugs
New NGK Wires
New Fuel Filter
OEM PCV Valve
OEM Oil Cap
Flow Tested 450cc Fuel Injectors
OEM Fuel Rail
Fuel Pressure Regulator
Rebuilt Throttle Body
New Crank Position Sensor
New Alternator
New Alternator Belt
New Battery
New EGR Valve
Timing Belt/ Water Pump
Air Filter
New Valve Cover Gasket
New Coolant Temp Sensor

 

[Mauispyder]

When was the last time your spark plug wires were replaced?

 

[JeffwithaG]

I have NGK Wires and Plugs, both have less than 200 miles on them. Gap on the plugs are in spec also.

 

[Vegas Smith]

It's not uncommon to see air coming out of the VC during a BLT at the turbo because the turbo seals are "dynamic" and seals under use. The air escapes the seals and goes down the drain tube into the oil pan. As far as your sputtering, it's difficult to say as that could be caused by many things. Next item I'd check/replace would be fuel pump

 

[JeffwithaG]

It's not uncommon to see air coming out of the VC during a BLT at the turbo because the turbo seals are "dynamic" and seals under use. The air escapes the seals and goes down the drain tube into the oil pan. As far as your sputtering, it's difficult to say as that could be caused by many things. Next item I'd check/replace would be fuel pump

Awesome, thank you. I will search around for a test and a replacement option if needed. Part of me is happy I'm going down this rabbit hole of finding the source of the issue as I am getting a lot of normal maintenance items taken care of. This community has been invaluable for the knowledge base and getting items from the Classifieds.

 

[motomattx]

Just to put it out there, NGK makes great spark plugs, their wires for these cars however, I have seen them brand new cause misfires, only to be fixed by swapping in used oem wires, Im not saying that its the problem here though, but just something to have in your head.

 

[JeffwithaG]

Just to put it out there, NGK makes great spark plugs, their wires for these cars however, I have seen them brand new cause misfires, only to be fixed by swapping in used oem wires, Im not saying that its the problem here though, but just something to have in your head.

I had some cheap, off brand $10 RockAuto wires on it previously. I could see them sparking in the dark and decided to replace them with the NGK's. The same issue was occurring with both sets of wires.

 

[AWD-Tony]

There's a write up on pcv system in dsm...they all leak. I put a one way check valve in the pcv hose and I hold 40 psi forever when BLT.

What did you gap the plugs to and which ngk plugs?
How much boost are you running?

 

[JeffwithaG]

There's a write up on pcv system in dsm...they all leak. I put a one way check valve in the pcv hose and I hold 40 psi forever when BLT.

What did you gap the plugs to and which ngk plugs?
How much boost are you running?

I will check out the write up, thanks. Wires are NGK ME77/8100. Pugs are NGK BPR6EGP. The car has the stock T-25 at stock boost levels.

I think the plugs are the culprit. I pulled them and they look possibly lean fouled. Also, i adjusted the gap down to 0.028 and the car ran way worse. I bumped it up to 0.034 and it runs way better. The bogging started at roughly half throttle when gapped to 0.028. Should I check out BPR7ES maybe? I can never which are better for stock turbo/boost levels.

 

[AWD-Tony]

6’s are fine for stock level. 7’s are colder plug. You’ll want 7’s when you make more power. Try gapping to .30 then.

 

[JeffwithaG]

6’s are fine for stock level. 7’s are colder plug. You’ll want 7’s when you make more power. Try gapping to .30 then.

Okay I will try that out tomorrow. I might try to swing by a store tomorrow for a new set just to be doubly sure.

 

[JeffwithaG]

Okay I will try that out tomorrow. I might try to swing by a store tomorrow for a new set just to be doubly sure.

I got some new plugs and gapped them to 0.030, same issue occurs. Bucking, popping at WOT. I can ease into boost all day., but once the accelerator gets to 70% is where the issues occur.

I'm going to test the coils and O2 sensor this weekend. After that, I have nothing left. I will look for a Mitsubishi/Evo/DSM specific shop to help out. I dont know anyone around my area with a lot of DSM knowledge.

 

[Vegas Smith]

It's possible your MAF sensor is going bad. I don't believe you can clean it so look into signs of a bad maf and decide if it's worth buying a used one to see.

 

[Vegas Smith]

Just to put it out there, NGK makes great spark plugs, their wires for these cars however, I have seen them brand new cause misfires, only to be fixed by swapping in used oem wires, Im not saying that its the problem here though, but just something to have in your head.

This inspired me to take out my fairly new ngks and throw in an old set of magnacores.....car idles much better with no miss. Bravo.

 

[JeffwithaG]

It's possible your MAF sensor is going bad. I don't believe you can clean it so look into signs of a bad maf and decide if it's worth buying a used one to see.

I have three 2g Mass Airflow Sensors, its does the same with all three.

 

[Vegas Smith]

I have three 2g Mass Airflow Sensors, its does the same with all three.

I didn't ask you how many you had. I said get another one! JK

 

[JeffwithaG]

In case someone searches this thread in the future, the issue has been resolved. The initial issue was related to the EGR Valve being "bad". This was causing the car to sputter along and you could gradually increase the throttle like a quarter of an inch at a time to about 30 MPH. New EGR Valve got installed and the car ran much better, I could actually drive it around town, but couldnt go WOT. After some additional troubleshooting (and help from a forum member), it was determined that the wastegate was malfunctioning (probably stuck closed). When you go WOT, the car was hitting fuel cut which was the bucking/hesitation I was experiencing.