Jump to content
SAU Community

Recommended Posts

Hi all this is my situation.

I have a 96 r33 gtst and when driving and coming to a stop and sometimes whilst driving the car will stall.

Whilst sitting at the light after stopping the idle of the car sometimes sits at 1k or 1.2k or even sometimes

after i have started it again it idles at 2k. If i rev it it drops back to normal 700rpm. Im thinking it may be the AFM.

My car has the following mods: cat back exhaust, bov, boost controller, pod filter. Any feedback would be greatly appreciated.

Price for a new airflow meter if that is the problem?

regards

jim

Link to comment
https://www.sau.com.au/forums/topic/179316-r33-gtst-staling-problem/
Share on other sites

so most probably it has a leak right? or if i can tighten it it will take more pressure to open up.

just a quick question how does the bov controll the idle and stalling. vaccum leaks i guess

No, it wont have a leak. Its just ATMO venting.

The AFM (near your pod) normally has the air re-circ back to it. The ECU expects it to be there and buy installing a pointless Atmo BOV, your sending the ECU into a fit.

To fix the problem for good you have two options.

1. Put the stock BOV back on (less than $100)

2. Purchase some management, pay for a tune (potentially over $1500)

BOV's are a pointless mod, much like pod filters. They offer not performance gain over the OEM gear, if anything they hinder performance

a bandaid fix for it is to get new spark plugs.

spark plugs?? i had the same problem the factory bov (when run in atmo)is held open a little by vaccum from the manifold which basically intoduces a leak into the intake system, the engine is taking in unmetered air, if it is adjustable just tighten it a little other wise vent it back and you shouldnt have a problem.

Edited by drf76
spark plugs?? i had the same problem the factory bov is held open a little by vaccum from the manifold which basically intoduces a leak into the intake system, the engine is taking in unmetered air, if it is adjustable just tighten it a little other wise vent it back and you shouldnt have a problem.

If it were a factory BOV you wouldn't have aproblem if it were open at idle for letting in unmetered air, as it'd just be allowing the same metered air to travel a different path INTO the engine.

If it were a factory BOV you wouldn't have aproblem if it were open at idle for letting in unmetered air, as it'd just be allowing the same metered air to travel a different path INTO the engine.

i always thought that it would cancel out due to the air being sucked into the turbo and air being blow out towards the throttle body pipe where the bov is mounted, taking of the bov recirc pipe stuffs the balance and causes air to be drawn in, its just like having a pcv valve connected with a catch tank that is vented, it would cause a vac leak through the rocker cover, thats why near the bov recirc pipe you have the breather for the rocker cover into the intake pipe (near the afmeter) to stop a vac leak to the manifold.

i always thought that it would cancel out due to the air being sucked into the turbo and air being blow out towards the throttle body pipe where the bov is mounted, taking of the bov recirc pipe stuffs the balance and causes air to be drawn in, its just like having a pcv valve connected with a catch tank that is vented, it would cause a vac leak through the rocker cover, thats why near the bov recirc pipe you have the breather for the rocker cover into the intake pipe (near the afmeter) to stop a vac leak to the manifold.

Turbo does nothing at idle.

Air comes in through AFM, through turbo, through throttle, into manifold.

If BOV is open

Air comes through AFM, through turbo (And also through the recirc pipe and comes out just before the throttle) and then into manifold.

Whilst the car is in vacuum. Air is being SUCKED not forced through the intake.

Turbo does nothing at idle.

Air comes in through AFM, through turbo, through throttle, into manifold.

If BOV is open

Air comes through AFM, through turbo (And also through the recirc pipe and comes out just before the throttle) and then into manifold.

Whilst the car is in vacuum. Air is being SUCKED not forced through the intake.

i know air is not forced into the intake lol wrong wording, its not on boost at idle, the suction before and after the turbo cancels out when you have the recircirc pipe connected so no air is being drawn through the bov, put it this way would it be good to have a small hole in the intercooler piping which is wat the bov is basically doing.

i know air is not forced into the intake lol wrong wording, its not on boost at idle, the suction before and after the turbo cancels out when you have the recircirc pipe connected so no air is being drawn through the bov, put it this way would it be good to have a small hole in the intercooler piping which is wat the bov is basically doing.

If there's a recirc ppipe, then that's like saying, with a hole in the intercooler piping, put an AFM so the ECU knows.

The air, even if the engine is pulling air through the BOV from the recirc pipe, the recirc pipe is still AFTER the AFM, therefore, it's affectively just "changing lanes" but it still went through the toll

If there's a recirc ppipe, then that's like saying, with a hole in the intercooler piping, put an AFM so the ECU knows.

no its only there on idle due to the high vacumm, so its sealed under boost, im just saying at idle low rpm with vacumm. Its too hard to explain, its exacltly the same a have a pcv valve with a vented catch tank almost the same thing. By the way Im basing this if the factory bov is run to the atmoshpere, i understand that if it run with a recirc pipe there is no difference it just taking a different path still to the throttle body, i think there was a misunderstanding MBS206

Edited by drf76
no its only there on idle due to the high vacumm, so its sealed under boost, im just saying at idle low rpm with vacumm. Its too hard to explain, its exacltly the same a have a pcv valve with a vented catch tank almost the same thing. By the way Im basing this if the factory bov is run to the atmoshpere, i understand that if it run with a recirc pipe there is no difference it just taking a different path still to the throttle body, i think there was a misunderstanding MBS206

If there's no recirc pipe, that's most likely one of the huge issues.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Hello, just just bought an 1999 enr34 with a stock rb25neo and I'm looking to upgrade the engine to 500whp I know some basic things but wondering if there are things I'll need to do to upgrade the stock block and all the bits and pieces to achieve this.
    • Thanks everyone for the replies and suggestions. Got the seats out (hoping I could find some existing grommets but no such luck). By tapping and measuring etc. I could figure out where I could drill through if needed. But first I borrowed an inspection camera and managed to go through factory holes in the chassis rail and could see that the captive nut was holding steady which is why it could retighten. So it was indeed a stripped section of thread, so I applied downforce by levering the bolt head with a screwdriver and went slowly back and forth until it came out. Camera helped a lot cos I could monitor that the captive nut was holding tight. Now I just have one very seized main subframe nut to tackle 😅
    • BOVs do have a purpose, if you ever log pressure before and after the throttle body, you will see a spike pre throttle on lift off from a WOT condition. Enough to bend throttle blades / damage e-throttle motors or simple assist in blowing off cooler pipes. FWIW, the above on really applies to those running at least 2 bar of boost. OP shouldn't have an issue, on the other hand, here are some videos of my shit box over a decade ago with some succulent dose with the airbox on and off. That shit box is unrecognisable these days 🫠    
    • I've tried all different combinations of BOVs/ no BOV and stock bypass valves over the years, on gear changes the stock bypass valve seems to get the car back on boost quicker because in part the turbos wheel speed isn't being slowed down by reversion, although they have issues holding boost much over the stock setting. Most aftermarket BOVs you can adjust the spring, tighter will make it open later and close sooner, but in my experience it'll cause a bit of flutter at low load/rpm anyway. I've also got some input into this whole no bov causing turbo wear, never had an issue on any on my turbos HOWEVER, I got my R33 GTST with 200k kms on it, with from what I can see still has the original turbo, no lateral shaft play but has about 4-5mm of play in and out which to me seems like a worn thrust bearing from years (100-150k kms?) of turbo flutter running no bov, so maybe there is some truth to it in the long run. But that'll never stop me loving the Stutututu while I have the car.   OP just wants to know if he can run a atmo vented BOV with no major issues and the answer is YES, plenty of people do it, there's no harm in installing it and seeing how it runs before spending $$$ on an aftermarket ecu, last time I bought a Nistune it was $2400 for install and a tune , unsure of todays prices but you get me. Crazy money to spend just to fix the minor inconvenience of stalling that can be overcome by letting the revs come down to near idle before putting the clutch in or a little bit of throttle to avoid it. You're better off leaving the ecu and tune for after a bigger turbo/injectors have been installed to take full advantage of the tune and get your moneys worth.   Let OP have his Whoosh sound without trying to break his bank haha
    • I see you missed the rest of the conversation where they have benefits, but nothing to do with avoiding breaking turbos, which is what the aftermarket BOV made all the fan boys, tuners, and modders believe was the only purpose for them...
×
×
  • Create New...