Jump to content
SAU Community

Rb25 Stalling Momentarily

Marcus89

By Marcus89,
in Forced Induction Performance

 Share

Recommended Posts

Marcus89 Proficient

Marcus89

Posted
Posted

My r34 rb25det neo has decided to develop a strange issue where I will be drifting and when I shift gears from 2nd to 3rd mid drift it will stall out just for a second causing it to bog down. Initially it happened rarely at the start of the night but got progressively worst as the night went on. It got the to point where clutch kicking it in 3rd (after having shifted 2nd to 3rd and had the stall out) would cause the same issue to happen again rather than for the car to start hooking up like it had done earlier in the night. I went to pits to try and find any potential air leaks or something along those lines but could not find anything and the car idles perfectly beautifully does not hunt. After being in pit for about 10 mins took it out for a run and it seemed to have no issue at all. Went for another go and the issue was back again.

Whenever I drove normally ringing out 1st, 2nd and 3rd gear there was no noticeable issue it only presented when I was drifting.

Engine mods are as follows:
Nistune
3inch turbo back exhaust
Hypergear g2.5
Bosch 550cc injectors
Oil cooler
FMIC
52mm Alum rad
Bosch 023 fuel pump
Still running recirculating BOV

I feel a likely culprit could be the fuel pump being on its way out. Does anyone think a fuel pump that's starting to run out of steam would present with these kind of issues?

Another option I was thinking was that my recirculating BOV could be leaking air out as some of the piping is a bit average and this could be a big enough difference for it to confuse the ECU as it doesn't see the air that it expected to be there.

I really wish the issue was something more obvious/severe as it seems so vague I don't really know where to start and unfortunately don't have the money to just start changing everything (crap job and going back to uni). In the end it is my daily and still drives perfect for daily duties at least at current.

Link to comment
Share on other sites
XGTRX Veteran

XGTRX

Posted
Posted (edited)

Does it come off boost with gear changes and is the rpm around the 3k mark, if so the mixture could be leaning out slightly when you come back on throttle. Just a thought.

Edited by XGTRX
Link to comment
Share on other sites
robjen Rookie

robjen

Posted
Posted

Might be completely off track here but a log truck I was driving did this cut out thing. It was too quick to log a fault code so after 12 months of looking poking, trying and several trips to cummins and brown and hurley and anyone else who might know something it ended up being the fuse holder in the battery box. Pliers on the fuse holder, squeeze, insert fuse, never another problem. Maybe not the problem but I always start by shaking fuses.

Link to comment
Share on other sites
Ben C34 Grand Master

Ben C34

Posted
Posted

Does it come off boost with gear changes and is the rpm around the 3k mark, if so the mixture could be leaning out slightly when you come back on throttle. Just a thought.

Is that based on something?

If the ecu Is tuned correctly there won't be any weird lean spots.

Link to comment
Share on other sites
XGTRX Veteran

XGTRX

Posted
Posted

Is that based on something?

If the ecu Is tuned correctly there won't be any weird lean spots.

Unless something is not doing/ or can't do what it is being told to do.

Link to comment
Share on other sites
Ben C34 Grand Master

Ben C34

Posted
Posted

Unless something is not doing/ or can't do what it is being told to do.

Of course.

I just wondered because you were specific with the 3000rpms I thought perhaps you had experienced or heard about something .

Link to comment
Share on other sites
XGTRX Veteran

XGTRX

Posted
Posted (edited)

Of course.

I just wondered because you were specific with the 3000rpms I thought perhaps you had experienced or heard about something .

Just mentioned it because especially in the OP's description it seems to be happening at a point where it may be transitioning off boost to on boost where if things aren't spot on a temporary lean condition may occur which is consistent with the occurrences the OP is describing. Just a suggestion anyway.

Oh and a guy with a 200 that was street driven had to add a heap of fuel in this transition area when he started drifting but it couldnt be done on the dyno, had to be done on the street.

Edited by XGTRX
Link to comment
Share on other sites
Ben C34 Grand Master

Ben C34

Posted
Posted

Really it could be anything.

It could be reversion in the maf causing a rich conditon.

They are fussy when it comes to how the bov is plumbed back to the inlet.

Mine carries on a bit sometimes due to this, but being an auto doesn't cause problems and doesnt happen often. I am going to change the angle the bov return is attached to the inlet pipe to make it point as much towards the turbo autos possible.

Link to comment
Share on other sites
Trex Grand Master

Trex

Posted
Posted

How much fuel did you have?

I had this problem when the filter at the end of the fuel pump was a tiny bit higher than stock, it would get worse the lower the fuel got.

skylines and stageas suffer from a lack of fuel when throwing them around. May need a surge tank?

Link to comment
Share on other sites
rondofj Veteran

rondofj

Posted
Posted (edited)

I have a 34gtt that does this on downshifts and especially under load, it bogs down for 3-4 seconds and loses 60% of power or even more, its that bad. I have recently found it sometimes does this on up shifts as well but only under load when shifting a bit early up an incline etc. My tuner found the map tracer cell in my power fc jumps 5 cells when it does this, pinpointing to a high voltage drop in my z32 which is possibly measuring more air from b.o.v. reversion n causing the ecu to retard timing n add more fuel. He said it is most likely my bov angle pipe causing afm reversion- not an ideal entry angle- see pic

post-49401-14028386776606_thumb.jpg

Edited by rondofj
Link to comment
Share on other sites
Marcus89 Proficient

Marcus89

Posted
  • Author
Posted

Cheers for the tips guys. I was thinking of BOV reversion being a potential issue rondofj I guess the easiest way to suss that out would be on a dyno although seems a bit strange it only really does it when I am sliding. I have put the BOV return pretty far down the intake pipe but it doesn't point that much towards turbo which isn't good.

I don't think it is fuel surge as I feel it would be even worst when transitioning back the other way and not just grabbing a higher gear while maintaining the same slide which doesn't really slosh the fuel around much.

I've started to think it may actually be a small intake leak that opens up more on boost causing the car to run real rich on boost (Will be doing a intake pressure test soon as it's easy and free)

Link to comment
Share on other sites

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • silviaz
      My BMW 335i

      By silviaz · Posted

      Gosh these bmw's are worse money pits than JDM's! I won't complain about my car anymore 😂
    • Murray_Calavera
      Newbie from VIC

      By Murray_Calavera · Posted

      I'll just leave this quick tip here after reading your joys of getting the car in the air. It should take no more then 10 minutes to get the car safely up on stands.  So for the front, jack on the tow recovery points (marked in red). Put the jack stands under the lower control arm mounting point (marked in yellow). This photo is of a R34 GTR, however the process is the same. For the rear, jack under the diff (marked in red). Put the jack stands under the rear subframe or where the lower control arm mounting point (marked in yellow). Which point you use will depend on your stand, pick a nice stable point.  You've probably already read this but it's worth repeating. When jacking up the car or using stands, stay away from the chassis rails/pinch welds. Even the factory jack point, stay away from that too unless using a factory jack. I used those jack points for years without issue until I turned into an old man and bought a QuickJack lol. 
    • DraftySquash
      Newbie from VIC

      By DraftySquash · Posted

      And this is where the leak is happening: https://www.dropbox.com/scl/fi/7h1vlmg2j5aa7rksvsjc9/IMG_9982.jpeg?rlkey=d3bnpau5f615zmxqmca0llvr7&st=kquvdxvs&dl=0   Apologies but it seems adding an image from a link does not work when the images are in Dropbox. 
    • DraftySquash
      Newbie from VIC

      By DraftySquash · Posted

      Here are some pics from the auction: https://www.dropbox.com/scl/fi/gkbfaa7urogzhyzxtdgq4/4cd77e2d-e19f-45fb-80a0-f9a88fd7f51f.jpeg?rlkey=39p7xyvgr33kj0avcjry2v4ap&st=ncxmagj4&dl=0   https://www.dropbox.com/scl/fi/gkbfaa7urogzhyzxtdgq4/4cd77e2d-e19f-45fb-80a0-f9a88fd7f51f.jpeg?rlkey=39p7xyvgr33kj0avcjry2v4ap&st=ncxmagj4&dl=0
    • DraftySquash
      Newbie from VIC

      By DraftySquash · Posted

      Hi all, From the western suburbs here. Just got my 2000 R34 GTT registered today! Got it imported from Japan through a mate who is doing them and managed to find a decent one. This one has only done 110,000 Km and had no body rust etc. so was very happy. I used to own a 25Gt back in 2015 (ate Ramen noodles for years to save up for it), but unfortunately, it got stolen TEN DAYS after I bought it!! Came back from Uni and the car was missing - cops found it in Springvale a month later with a lot of needles  😒 It was too late by then and I had moved on to a different car (300ZX), and after that one got broken into around 2018, I was in a very bad place and decided I would never buy a car again because it was just pointless!!! ~yeah, I have some very bad mojo~ 🥺 But now, with a stable job and a secure garage, I thought I'd get the R34 4D again but not as a daily! I love the R34s but a GTR is still a bit off my pay grade so settled for the GTT instead.    The first step for me is to get this car serviced and have all fluids, belts and spark plugs changed. I might do the brakes at one point too but atm they are fine, the fluids are what I want changed since this car probably sat in a garage for a long time. I'll then get some coilovers since the suspension needs to be changed anyway (the dust cover kit is disintegrating). I'll also upgrade my car alarm to a Viper system and then look at rims and tyres (I'm a sucker for TE37s - might have enough saved in another 3 years for that).   Today: I was planning to do the oil, coolant, air filter and fuel filter change this week. Started on the oil change today and MY GOD what a pain!! I used to think the 300ZX engine bay was cramped - oh I was so wrong! 😂 I've done the usual services on my cars before so it was not like I was going in blind. I looked up all the forum details about what oils to use, what coolant to use, what points to use to jack the car or place stands etc but I did not expect it to be this hard. Long story short - all I managed to do was the oil and filter change. I think I might end up taking it to a mechanic for a coolant change because my SCA stands and trolley jack just can't get far enough underneath to the cross-member and I don't want to be crushed under my favourite car....yet. Side note: In Dandenong, there used to be a shop that lets you hire their hoists - does anyone know if they have those around? I can't seem to find the Dandenong place anymore. I contacted them off FB almost 6 years ago and I'm not in it now. If anyone know of one, that would save me some time going to a mechanic for the basic services. Oil: Dark and gooey but no metal pieces. Oil Filter: Was a b***h to take off but no red flags Air filter: Yucky! Was black (Smells like fuel which makes me think it may have been running rich? - am I way off?)   Concerns: I have but one concern atm and that is that there was a very small amount of oil leaking where the engine and the transmission connect (Automatic). It may be the rear seal? It's not a massive leak and it does not affect the oil pressures or leak oil all along the driveway. It's been falling into the cover this whole time. I've taken the cover off so I can check the garage floor from time to time.  I also have not seen my engine temperature gauge ever sit at cold and slowly move up to the right spot, but that might be because every time I saw the car today, it was running. I'll check that again tomorrow. ATM it just sits right in the middle. I may just be paranoid but I don't want an overheating engine while my gauges say everything is fine. 🙈 Other than that, I'm very happy with the car! Feels like it's about time I went back to spending my weekends driving or cutting my arm on stupid sh*t in the engine bay.   PS: I will post a pic later on because I underestimated soooo badly today and it was dark by the time I finished! PPS: I broke the two damn plastic pins that hold the intake funnel section to the front bar. This is the piece made to bring cold air to the airbox. The connection to the airbox is fone, but the two clips just broke off! Should I be worried? Anyone else done that? 
×
×
  • Create New...