unusual hesitation/miss silvia sr20det , sadly now need help

[Jcollison016]

hey guys i want to start off by introducing myself, im john from Baltimore i some what recently picked up a rhd 240sx "silvia" if thats what you want to call it. anyways ive tried sorting this out a little bit with some but not to satisfying results, basically at crusing throttle it had a slight miss or hesitation with a small backfire super annoying as its my DD well i figured lets start simple maybe my spark plug gap was off, plus it was time for new plugs anyways ngk bkr7es. so my old ones were gapped at .035 so the new ones were to be gapped at .032 to see if there was any noticeable improvement sure enough right away the first day or so it seemed fine idle was smoother cold start improved. but now a few days after that the miss/hesitation is back on occasion not all the time, but when it comes its back with a vengeance, it will start doing it going down the highway and get to the point where my engine will stop firing for a few seconds and die out untill i jam the gas and she returns to runnung, she runs fine when im into boost except at wot on occasion also where it will hesitate also which could be a simple boost leak that i will get to eventually, but first i want to fix this problem to see if it has anything to do with that. also when i first start driving it and after driving for awhile it will want to stall when i pull off in first also missing for a few seconds, even stalling all the way out sometimes. my only diagnosis at this point would be that the rfl and its horrible seal are pulling so much vac and causing it to go lean and for this to happen? anyone else have a similar problem any input is greatly appreciated guys!

[2_Liter_Turbo]

If you have a vented blow off valve and you are still using a MAF, a faulty bov could be your issue. Also, pull the plugs again and check to see how everything is running. If you've been running way too lean and burning up the plugs, it could have ran fine for a bit and then gotten worse as the electrode gets burned away. Hopefully that's not the case, and it's just a leaky BOV. These cars are very picky (when using a MAF sensor) to boost/vacuum leaks. They will run like poo if everything isn't spot on. Try blocking off the BOV and driving it around (without going full throttle) to see if it goes away.

[Jcollison016]

im gonna go give that a whirl real quick, i have a feeling its just running lean honestly. thank you will return in a few minutes

[Jcollison016]

problem persists maybe a touch better but i didnt want to cruise for miles with my bov shut, theres still another side to this problem im still on oem fpr you think that may have something to do with it, didnt pull plugs yet but both times i did previously they all were pretty consistently white with a touch of brown/gold/yellowish color. i should have also mentioned when i changed the plugs last it was because i couldnt hold crusing speed at all just half throttle then off the gas had to do that all the way home

[Jcollison016]

If you have a vented blow off valve and you are still using a MAF, a faulty bov could be your issue. Also, pull the plugs again and check to see how everything is running. If you've been running way too lean and burning up the plugs, it could have ran fine for a bit and then gotten worse as the electrode gets burned away. Hopefully that's not the case, and it's just a leaky BOV. These cars are very picky (when using a MAF sensor) to boost/vacuum leaks. They will run like poo if everything isn't spot on. Try blocking off the BOV and driving it around (without going full throttle) to see if it goes away.

sorry i dont know if i have to tag you or something for you to see i responded

[2_Liter_Turbo]

No, I don't have auto notifications setup, lol, I was just out in the garage. As for the FPR, you'd have to get a fuel pressure tester to see if it's functioning correctly. From the left, I see you're on 740cc injectors, walboro 255 and some cams. Which turbo are you running? Do you have a wideband air/fuel gauge? If so, what is it reading?

[Jcollison016]

i believe it is a 50 trim, a rebuilt godspeed turbo bench balanced 11k rpm aka ebay, but thats temporary my buddy has a 6262 fs i may grab but i think its a little smaller then im looking for i have a afr gauge but no controller yet i haven't broken the bank on these little things yet because i have a feeling im gonna have to fix something major or rebuild it entirely. is there any reader that will tell me the afr's on a dyno at a local shop, there is a shop just down the street called ma motorsports apparently they do awesome work, last time i was in there they had vaughn gittins old mustang in there but would they have a tool to read them? or is it a wideband only kinda thing

[2_Liter_Turbo]

i believe it is a 50 trim, a rebuilt godspeed turbo bench balanced 11k rpm aka ebay, but thats temporary my buddy has a 6262 fs i may grab but i think its a little smaller then im looking for i have a afr gauge but no controller yet i haven't broken the bank on these little things yet because i have a feeling im gonna have to fix something major or rebuild it entirely. is there any reader that will tell me the afr's on a dyno at a local shop, there is a shop just down the street called ma motorsports apparently they do awesome work, last time i was in there they had vaughn gittins old mustang in there but would they have a tool to read them? or is it a wideband only kinda thing

They would definitely have something to read your AFRs, but having them diagnose (or any shop) what's wrong will cost a bit. I would definitely get rid of the godspeed turbo as soon as you can. With parts like that, you'll be chasing gremlins forever, lol (assuming it's not the only ebay part on the car). If you have a known boost leak, I'd definitely fix that before going any further. Also, check out he coolant temperature sensor (the two wire one, not the single spade one), as that sends a signal to the ecu for operation as well. I had one go out and the car ran horrible, spent $20 on a new one and it was golden. If you don't have a factory service manual (for checking sensors, etc), go to the link below, we offer them free of charge.

240SX FSMs