S14 slant top Sputtering and breaking up in boost

[street_white180sx]

Hey guys i am a little bit stomped here. I have a S14 Zenki Silvia with a slant top motor. The problem i am having right now is when i am going in boost my car will sputter and fall flat at times or it will break up. Here is the checks that i have already made thus far.

Checks for Codes in the system only came up with code 55 which means no problem present. Changed plugs put sum ngk V powers in number 7 heat range. Found the fuel filter was dirty replaced the fuel filter and the problem is still present. Ohmed the ground side on the coil pack harness resistance is ok. Check fuel pressure at Idle 36psi ,when full throttle pressure jumps to about 50psi. Checked MAF voltage and voltage checked out OK. Checked TP checked out OK. Ohmed Ignition coils checked out ok. After all of these checks i am kinda stumped to what the problem is with my car.

What other Checks can i make or is there any suggestions to what my problem possibly could be.:-/

Also Mods to Car are HKS air filter, HKS EVCIII, stock dp with 3 inch catback gutted cat runnin 0.8 bar and FMIC

Can it be dirty injectors or possibly anything else. Please this is my daily driver.

[street_white180sx]

Any Ideas?

[codunc]

What fuel pump are you running?

[Anomas23]

Are you using stock BOV? and are they're any leaks going to it?

[street_white180sx]

running a blitz BOV. The pump is still stock but my pressure isnt low so i didnt suspect the pump to be bad.

[street_white180sx]

Any help with this problem?

BUMP

[Dousan_PG]

spark plug gap?
did this problem show up out of no where?

[street_white180sx]

Gap is .28. 1st it wud go away when it got warm now its pretty much continuous.

[guitaraholic]

I had a bit of the same problem. And this is where it got kinda weird, for some reason the boost was showing around 7 psi, but I had it shared with the BOV and the WGA was on its own nipple. I would run fine on normal driving, but if I hit boost with anything more than 1/2 throttle it would sputter.
I found out later after switching the vaccuum lines around that my WGA was broken and I was hitting 17psi and I guess the fuel was cutting off. Although when I first got the car up and running after the swap I hit 17psi before without any cut (yes it was stupid could have went BOOM but luckely it didn't, it just started doing it out of the blue after 4 or 5 months.
I tried looking for boost leaks, and everything else. Well, I was in the process of upgrading anyways (injectors, ECU and MAF), well, after that it fixed it fine 17psi and no probs. I got and HKS actuator now and usually run 10psi or so.

So, try this,,, see if your car is able to accerate under say 1/2 throttle or so (its kind of like modulating boost with the thottle). If you are able to hit a little bit of boost then you might have the same prob I did. I never really figured it out, but upgrading those three fixed it.

Hope this helps you a little maybe.

[fliprayzin240sx]

Double checked the timing? Check if its good then im thinking water temp sensor. When you said its fine on start up but gets shittier when the car gets to operating temp.

[street_white180sx]

nah at 1st it was shitty on start up and then it wud clear up when warm. still feeling the coolant temp sensor?

[street_white180sx]

Its actually got worse. As soon as i boost to 0.3 bar it breaks up and when i turn up the boost more it gets more violent. Should i pressure test the system for leaks?

[slider2828]

Sounds like coolant temp sensor and check your couplers.

Did you hit anything? When you pulled your plugs... where there any discolorations?

Sounds more like a coupler problem to me.

[slider2828]

Did you check your exhaust to turbo area to see if the gasket cracked or leaking anything? Do you hear anything different in the engine area?

[street_white180sx]

Nah no exhaust leaks. I checked over all of those things. Me and my friend are supposed to pressure test the system tomorrow and check for any leaky couplings because visually i see no leaks or tears. Before i changed the fuel filter the plugs were white. now they are brown which indicates a good burn. I work to a ford dealer and right next is the nissan dealer so maybe i can ask one of the guys to use the consult on my lunch break and take a look at whats goin on. Is there anything i should look for with the coolant temp to check if its bad besides the resistance because i dont have my meter on me.

[street_white180sx]

Well i finally found my problem. Apparently the heat from my manifold decided to slowly heat away the insulation on the wires on the connector for the coilpacks causing the wires to touch together causing my infamous popcorn machine from the exhaust. So i will have to repair the harness and see whats up.

[RedStage]

any further problems with this?

mine has started to do similar.
First happened yesterday.