Jump to content
SAU Community

Recommended Posts

hey guys,

I am experiencing terrible bogging down at low revs in my R33 GTR V-Spec in the past 2 months or so.

eg. If I am wanting to turn left onto a main road, my car will struggle to bring up its revs. So it will hover around the 950rpm / 1000rpm mark for a considerable amount of time, before it builds up and I can take off.

Most of the time when it happens.. I will roll very very slowly, I can count from 1 to 5 at least before it starts to gather some revs and move. And it can happen at the lights at times, so I can imagine people behind me will be like get a move on, wtf is going on.

on maybe 2 occasions i felt a very slight 3 or 4 light jerks while it was happening. but mostly it is smooth just very slow.

I reved through to 7500ish yesterday, seemed to get up there fine, hit 12.1 psi

..if i launch off at around 1500rpm or 2000rpm the car will get away nicely.

Ok the numbers...

On my power FC it idles on 20 degrees timing, which will drop slightly to 18/19 degrees during the occurrence, when it picks up it seems to increase normally, no crazy jumping around..

I know idle is supposed to be 950 on the RB26, currently it is jumping between 871-929rpm.

The boost vac is sitting on -13 after a test drive.

Are these numbers about right or in the ok range? Or are there some discrepancies there that will give me a clue?

So far I have:

1) Replaced plugs with new spark plugs & fresh oil / oil filter change

2) cleaned up air pod filters

3) cleaned AFM with CRC CO Cleaner - stuff that leaves no residue

4) Replaced fuel filter

But none of these things have made any difference. Current tank has injector cleaner in it.

ohh.. and when bought the car, it did once and a while back fire, its become more frequent these days, happens when releasing throttle to change gears sometimes, or when slowing down and releasing the throttle.

In terms of mods, it is pretty stock, just running pod filters, front pipe back exhaust system, Power FC

Any help is very much appreciated,

Thanks :)

Edited by Skysthelimit

thanks for the suggestion..

I've tried to check for them the best I can...

I have gone around and tightened up the all the hose clamps I can see.

I can not hear any leaking, all the hoses seem to be in good condition, its hard to listen for any leaks with the loud exhaust. Whats the best way to check for leaks?

Edited by Skysthelimit

Either pressurise the intake with compressed air while the engine is off and search for leaks. Or while the engine is idling, grab a can of carb cleaner (or similar) and spray around pipes, gaskets etc. The idle will change (raise) as the engine sucks in the spray.

either vaccum leaks or could also be clutch slipping. i had the same problem and i thought it was my terrible diff ratio until i tried to launch last night and car didnt go anywhere but clutch slipped

Cant be clutch as he said it was fine on launch. Also the clutch will slip, revs will rise, speed wont.

It the car coughing, spluttering, popping at all? My car would just not drive below 2krpm but was worse up top. I had two problems. Initial problem was failing fuel pump so I was lean popping everywhere. After that was fixed, I was running too rich and the plugs were fouling up.

Vacuum leaks are easy to find. Everything under the bonnet should sound smooth, no weird or unwanted sounds. Get a short piece of hose with dia. about 5 cent coin, put one end in your ear and the other go around the engine bay. It will help you hear a leak without hearing other engine noises. If you are in neutral and you raise the RPM to say 1100 does it hold? Or does it pop and choke on itself.

thank you for the suggestions guys :) ..

the car lets out two exhaust pops on gear changes.

..I don't think clutch, same reasons as SargeRX8 stated..

put on my other boost gauge, has different measurement for vacuum.. getting 300mmHg at idle is that low?

when decelerating gets to 500mmHg

if in neutral and hold revs at 1100 it holds fine, smooth, as well as any other revs I try in neutral

Hmm. Vac sounds a tad on the low side. Check your cam timing - just incase.

Edit - otherwise still sounda like a vac leak of some form.

Edited by _x_FiReStOrM_x_

mine is doing a very similar thing as well. get alot of backfires, changing gears it pops, decelerating and just touching the throttle will backfire and idle is very rough

doesn't have the get up and go as i thought a gtr would have.

got a funny noise happening under the bonnet as well but have put that down the a small leak in the BOV's when the car is not under load. same sort of mods as the op's as well.

car is running very rich at the moment so for a tune next week, hope that sorts out the backfiring and idle issues

hmmm ok, thanks for the ideas guys :)

I'll have to get it checked out by a workshop I think, tried the hose to ear thing to look for vacuum leaks but couldn't find any.

Eric, who you booking it in with? I think I will get mine booked in also for a dyno tune and try and sort the issue out.

is normal vacuum at idle 500mm/Hg? I remember reading that somewhere, but not sure if I remember correct.

Edited by Skysthelimit

I go to Aaron at ITP Racing (used to be In tune Performance) in Bibra lakes(SOR), Its going in next monday, going to change the cat today to a highflow unit and will do a oil/spark plug change on friday. will also check all the pipes and vacuum lines

http://www.intuneperformance.com.au/

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

    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
    • So, a bit of a side trip, but one that might be interesting for people with JDM cars and japanese head units. I know @Pac previously posted about a carplay/android auto adapter he installed which used the AUX input, and @V35_Paul put in one of the Tesla style units that replace both screens. The option I went with was a Lsait LLT-YF-VER5.87_2 (https://www.alibaba.com/product-detail/Lsailt-8GB-Android-Multimedia-Interface-for_1601187633672.html). Price was $1,150 for a single unit although they are much cheaper if you are willing to buy 2....$857ea. Make you you get the version 2 not version 1, it is faster and has a better UI - this is the manufacturer listing: http://www.lsailt.com/product/348.html. BTW if you've never bought from Alibaba before, don't be concerned....these guys can't stay in business unless they are responsive, ship fast etc, they were excellent (probably faster shipping than most local places) So, this was my task for a lazy Sat afternoon....looks complex but was all done in a few hours (it probably helps that I had some of it apart before so it was a bit familiar). I also decided to add a HD USB drive recorded at the same time and the unit also supports an aftermarket reverse cam (if you don't want to retain factory) and also AV in and HDMI out It looks much worse than it is, in fact in was genuinely all plug and play (no custom wiring at all). This video was pretty good (skipped a few steps), unfortunately they are an Aussie seller but no longer sell this unit (I guess Carplay/AA adapters are easier to install and much cheaper) https://www.youtube.com/watch?v=T5hJfYOB8Dg
    • That still isn't a lot to go on. I don't have a Y50 Fuga Head Unit wiring diagram. I can say that a lot of nissans of that age shared head unit plugs, so if you are in Australia something like this would probably help: https://aerpro.com/app091# You plug that into the car loom, then either plug the head unit ISO into that (if it has ISO), or you buy and ISO adapter harness that you wire in. Bit of stuffing around, but once you have ISO its easy to change things in future.
    • It is a kunfine Android screen . Does anyone know the wirering diagram of the fuga ??
    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
×
×
  • Create New...