Jump to content
SAU Community

Recommended Posts

Hi all,

I have an R33 S2 GTST manual wit low ks in good condition. always serviced and only mods are a turbo back exhaust, bmc filter in std airbox and an r34 gt-t intercooler.

Right, now the car has a intermittant fault and I cant pick what it is. It used to do the typicall near stall issue where the rpm would drop then bounce up then drop again. I cleaned the aac valve as per the diy thread and it was fixed! great!

After a while it started doing something similar and i noticed a vac drop on my boost gauge, the car did the same thing, felt gutless and smelt of fuel. I found a vac leak which fixed that problem. great!

now the damn thing has come back again but its very intermittant. Somedays it will be completely fine. sometimes it will play up (eg of the fault, slow to the lights push the clutch in and the rpm will drop almost to 0, bounce up high and then slowly settle, when I try and take off it will hesitate and then settle. now whats weird is i cleaned my afm the other day and it went away.) NOTE when it happens the vac reads lower on the gauge but it goes back to normal idle reading when this problem dissappears.

After a while it did it again and the cleaning the afm didnt seem to fix it. i reset the computer and it went back to normal and after a few weeks it happened again...

I dont get it?? Any ideas?

(note. car has new plugs, coils are in good nick, it dosnt misfire, new fuel pump and filter, only run 98 etc etc)

Any ideas appreciated!

Thanks

ok new development. really need some help with this one guys.

The car seems to be worst when its cold. once its at FULL operating temp (say 15mins after starting) it seems to be ok, although the vac is still a touch low.

I also reset the computer last night (discharged for 12hrs) and no change so thats ruled out.

Also when the car starts the fluctuating idle, if i take off and give it a little bit of go (just typical acceleration) the car seems to hesitate and stutter back and forward while accelerating then over a certain rpm will come to life. maybe this can help diagnose it?

Any help is VERY appreciated

thanks

Edited by TUF250

already done, replaced plugs note even 5,000 ago with bcpres with a 0.9 gap (car runs std boost) and coils checked out fine.

remember its an idle hunting problem and the car stutters and pulses as you accelerate then picks up all lost power at about 2500 to 3000. if it was coils it would show up in the higher rpm band from what I have read.

im going to try a replacement afm tonight and see what happens

keep the ides coming.

there seems to be alot of people that have had this issue but no one has posted up their results

Glad u sorted it, I've been following this as I occasionally get the same problem.

Do you also get bad fuel economy? Sometimes I get bout 250-275 from a full tank with mixed city and country toad driving. That's about 14-15 l/100km which isn't good.

Does the afm get used in fuel calculations all the time? My other car has a MAP sensor instead so wondering if the AFM does the same. The other thing might have been O2 sensor but that would give you rough running after warmup if it wasn't working.

yeah i replaced my 02 sensor a while back. got it from bursons for about $100. When the car was carrying on, which didnt happen all the time the economy was bad. but once it settled it seem to go back to normal. afm can dictate mixtures to a degree but when it was playing up you could smell fuel. probably the computer trying to compensate.

you can buy them new from nissan. would be big $$$ though. Look around in the for sale thread. usually some floating around otherwise put an add up in the wanted dection. i did and got heaps of replies

Hi all,

I have an R33 S2 GTST manual wit low ks in good condition. always serviced and only mods are a turbo back exhaust, bmc filter in std airbox and an r34 gt-t intercooler.

Right, now the car has a intermittant fault and I cant pick what it is. It used to do the typicall near stall issue where the rpm would drop then bounce up then drop again. I cleaned the aac valve as per the diy thread and it was fixed! great!

After a while it started doing something similar and i noticed a vac drop on my boost gauge, the car did the same thing, felt gutless and smelt of fuel. I found a vac leak which fixed that problem. great!

now the damn thing has come back again but its very intermittant. Somedays it will be completely fine. sometimes it will play up (eg of the fault, slow to the lights push the clutch in and the rpm will drop almost to 0, bounce up high and then slowly settle, when I try and take off it will hesitate and then settle. now whats weird is i cleaned my afm the other day and it went away.) NOTE when it happens the vac reads lower on the gauge but it goes back to normal idle reading when this problem dissappears.

After a while it did it again and the cleaning the afm didnt seem to fix it. i reset the computer and it went back to normal and after a few weeks it happened again...

I dont get it?? Any ideas?

(note. car has new plugs, coils are in good nick, it dosnt misfire, new fuel pump and filter, only run 98 etc etc)

Any ideas appreciated!

Thanks

Yeah I'm having an issue like this with my '93 R32 GTS-t. I'm running a big stereo as well which, when playing beats, increased the gravity and frequency of the near stall/hesitation on moving off from idle and hesitation in low revs.

With this in mind, I started by replacing the battery as it was proper fu**ed. This improved things 10 fold as the new one has 580 CCA and can handle the stereo as well as the cars electrical needs but I'm still getting the occasional hiccup (which 99% of the time occurs when I stop and pick a friend up, but is only present for a few seconds.

I think AFM will be next - I'm gonna give the z32 a clean and see what happens.

If cleaning the AFM doesn't completely eliminate the problem I'd be testing the ignitor chip and the voltage to the fuel pump.

I have new splitfire coil packs, recently regapped plugs and I have recently replaced fuel filter.

I'll let you know how I get on with mine but this seems to be a pretty common issue with the early RBs (20 and 25).

Your latest problem, does it tend to happen when the car is warm? Ie. seems to run ok when cold, but starts playing up when the car warms up?

What does it mean if it does this while its warm?

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

    • Old Son, did you re-use the Holden ABS in the new shell or try a different module?
    • Yeah, nah. I had the actuator rod off it today. The arm will not move at all. Neither out, nor in. Yeah, you'd think so, but I've been thinking about that. Even when the actuator rod fell all the way off at the beginning of this saga, it would build more boost and faster in lower gears than it would in higher gears, and you'd think that that was the opposite of what should happen. But I strongly suspect that there is a thing with the gearing getting the revs to rise faster, that there must be some transient effect with the gas flow rate rising quickly, that you don't get with the more steady state case of the higher gears. Keep in mind - the gate is not shut in either of my weirdnesses. So things are not "normal". We normally think about a turbo spooling up (below the wastegate target) with the gate shut. I have all sorts of mental models running now where the gate is a little bit open, and having it stuck open allowing gas out while it should be going through the turbine has all sorts of weird effects (in these mental models). I'm thinking in the higher gears, the ex mani pressure builds to the point where enough gases spill out the wastegate to just prevent the pressure rising much more at all, or just creeping up, all the whole the revs are increasing and getting closer to the point where a gear shift becomes necessary.
    • Is it possibly wastegate actuator itself is sticking, or even the rod to flapper? Otherwise I reckon things are getting a bit rusty/worn   Also odd it won't boost in 3rd to 5th, but will in 1st, I'd expect the other way around with it slightly open as there's more time on your way to redline for it to spin up
    • Does anyone know ow what these two plugs are for and if they should be unplugged? Just put the dash back together and can't remember if these were plugged in before or unplugged! (Blue and white plugs) 🤦🏽‍♂️
    • Did some FASTing ...got the impression that the actual part# was a moot point ; seems all of these hardlines for coolant are discontinued/NLA... like, I take it you're after the hardline that bolts onto to the manifold...that's NLA according to amayama & nengun .... ...just to clear up some confusion, they typically mounted the AAC valve to the intake manifold somewhere near a coolant passage, so the body of the valve heats up & holds it open when engine's up to temp - no coolant flows through the valve, it's a mechanical, thermal connection.
×
×
  • Create New...