Jump to content
SAU Community

Recommended Posts

anyway cruising home from work this morning get past the roadworks accelerate from 40 in second a few seconds in and wham feels like i hit a wall a second later it takes off again. its never happened before so kinda random, but yer i just thought i would ask.

Have you changed anything recently, boost levels, front mount etc?

Rich and retard feels like a misfire, and typically happens in the mid range (From my experience). It happens due to the ecu reading a large amount of airflow and it subsequently dumps fuel to compensate, thereby protecting the engine from running lean. If you have modified the amount of airflow through your system by increasing boost, adding a larger intercooler etc then you may reach the R & R condition. If you haven't increased airflow, and nothing could have perished/broken to cause this condition then it might be your plugs or coils, it 'feels' essentially the same.

If you have reached R & R because of mods, it's time for, HKS FCD, SAFC/SITC, nistune etc etc so you can either clamp voltage or modify signal inputs (Depending on which fix you choose) to tune it out :P

Good luck!

yeah a couple weeks after i got my stag i had one of my coils fail. felt as you described. over the next week it happened for longer periods until the coilpack completely died and it would only run on 5 cylinders. felt like crap too

my car hasnt had any mods done recently, but current mods are - jjr dump pipe, empty cat case, hks hi power cat back, jjr stealth intercooler, splitfire coilpacks, k&n panel filter, turbosmart type 3 plumb back.

i could describe this feeling like speed cut but at 70km/h like it feelt like for a second the engine turned off

i have been thinking about trying to fix the tune but i cant really decide what to do. im leaning on either a haltech, nistune or mines ecu.

was it cold?

could be that you were just a tiny % away from hitting r&r but you never did, but now its getting colder over night the air in the morning could be more dense = afm reads as more air flow

go out in the heat of the day and see if it does it

if it still does it then you could be unlucky and have a bad splitfire (uncommon but happens)

make sure ur tyres are all evenly worn i had a kindof a misfirey / jerky sensation and it turned out to be the ATTESSA system being silly cos of uneven wear! back tyres < front will cause issues, but front < back will not!

i was spitting it cos i hadn't chaged anything and was bewildered as to why it was having issues! :P

if its not that, the cross it off the list :P

Sounds like fuel cut to me.

Any idea how much boost you were pushing?

I know when I push my car hard, I get fuel cut when the boost hits 1.3bar which can happen around the 70-80kph mark

(surprised the crap outta me the first time, felt like I was going to go through the windscreen)

according to the temp sensor behind the intercooler it was 21 degrees. all of my tyres are pretty new, i cant spin the rears without the fronts doing the whole torque steer axle tramp thing so i dont try anymore. the highest my boost ever gets is about a mm or 2 below the top line on the boost guage.

I'm with iamhe77, how much boost are you running? Or better, did you notice if you had a boost spike as it happened? It sounds just like the neo's boost cut, which as you said feels just like the engine completely cut for a second.

I'd say fuel cut as well. R&R will just make the car sluggish for a while (it runs incredibly rich) and usually it doesn't revert to normal until you lift your foot.

My s2 used to hit the fuel cut limit around 10-12psi with a GT30 turbo. It was sudden and pretty sharp, but then power would kick in again a moment later.

As I understand it, R&R is if it detects more airflow than it thinks it can handle, and the fuel cut is when it detects an extreme case of increased airflow. I think its kind of like the ecu panicking. I'm not sure if the fuel cut is boost-level related as well.

Some form of tuning should help eliminate it, otherwise just turn the boost down a bit.

Edited by pixel8r

Listen carefully because I am going to say this only once...(have said it many times before though..)

1. R&R is the ECU richening AFRs and retarding timing.

What triggers this?? Excessive knock picked up by the knock sensors...Once triggered the ECU creeps back to normal maps gradually over time...

The intent of R&R is to protect engine from damage (due to pinging) if car is filled with bad or low octane fuel...

2. Airflow cut is triggered when AFM voltage exceeds a mapped threshold (has nothing to do with R&R). Threshold voltage increases with engine rpm. When triggered ECU instantly drops fuel and spark. As soon as AFM voltage drops, fuel and spark get reinstated. Thats why if you dont back off throttle car will behave as if it is missing very badly..There is no adjustment to maps.

What triggers this?? Anything modifcation thats will results in significantly increased airflow into the engine as measured by the afm..ie Less restrictive intake, Less restrictive exhaust, higher boost, bigger turbocharger..

The intent of airflow cut is to protect engine from overly lean AFRs and/or damaged to turbocharger due to excessive spooling should there be a problem with boost control..ie split WG actuator hose or WG jammed actuator...

Contrary to common belief, these features were not placed in the ECU by the CIA, NSW highway patrol, RTA, FBI, nor are they some unexplainable scientific phenomona etc etc. They were simply put there by Nissan engineers to help get their turbocharged cars through a warranty period...

Hope this makes sense...

Good explanation Paul, but to add to what you said, the NEO RB25 in the R34's and S2 Stagea's also has an additional overboost protection, "boost cut", detected by a MAP sensor that the NEO has. Usually hit around the 13-14psi mark, but I have heard of people hitting it earlier.

mine did that . it only did it at about 6 grand in 3rd . standard boost controll with exhaust upgrade and front mount . ebc fixed it . it also only ran 5 psi after it did it untill i turned car off

my 33 used to do this on cold mornings when i was running 13psi, and only at 100% throttle. once the car had a bit more warmth in it (like had come up to full temp and then driven a bit harder) it would stop. if the car had only just come up to temp and you gave it the beans it would do it, but then a few mins later it wouldn't. i just put it down to having the boost set at the limit of what the ecu liked. for me it would happen at about 3000rpm and it felt like someone had just turned the key off and then back on. had it happen in second once and when it kicked back in it started to light up the rear tyres.

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

    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
    • You haven't driven many modern cars then have you? Most of them have sfa steering feel with their stupid electric bullshit steering systems.
×
×
  • Create New...