Jump to content
SAU Community

Fuel Cut When Cruise

YangLIU

By YangLIU,
in Four Door Family & Wagoneers

 Share

Recommended Posts

YangLIU Rising Star

YangLIU

Posted
Posted (edited)

Hi buddies,

just changed high flow turbo and spark plugs.

now i found there is random fuel cut problem:

1. when keep around 40% throttle on acceleration and get around 8-10PSI. sometimes i will get fuel cut once suddenly, boost pressure is gone. at this time, if i press acc pedal a bit more deeply, and make more throttle, then the car will keep acceleration and make more boost.

2. when cruise on motoway at 110km/h, just keep around 20-25% throttle on acceleration. it is about 2500-3000rpm and around -5PSI. sometimes i will get fuel cut too, just suddenly feel fuel cut and boost go down to -15PSI. I need to press acc pedal more deeply then the car will accelerate. it makes hard to cruise at 110km/s. i found there is no problem when cruise at 80km/s,90km/s,100km/s.

all fuel cut problem is just a second. all i need to do is press acc pedal more deeply

i keep my eye on boost gauge and AFM voltage, no problem when i got fuel cut.

any idea for this? :woot:

Edited by YangLIU
Link to comment
https://www.sau.com.au/forums/topic/459213-fuel-cut-when-cruise/
Share on other sites
YangLIU Rising Star

YangLIU

Posted
  • Author
Posted (edited)

Just because you have it doesnt mean thats why. The P0235 code is unexpected overboost. Clear the code and see if it helps. I had a hdi ebc and didnt constantly have the code.

i heard this from somewhere:

if the car is cold, then stock ECU will not allow high boost.

so if you are running EBC, you will easily get P0235 error.

but actually when i got fuel cut, the boost is less than 12PSI. i think there is no overboost?

how about remove/block stock boost sensor (for stock boost controller, not for the gauge)?

Edited by YangLIU
YangLIU Rising Star

YangLIU

Posted
  • Author
Posted (edited)

I have removed the gauge boost sensor. I still have the boost sensor that is near the bov. Have you taken your car to a mechanic or nissan to run a consult on it.

i haven't ran on consult. I just run cell code procedure every time. any difference between consult and cell code procedure?

i think the problem is not related to stock gauge boost sensor.

Edited by YangLIU
scotty nm35 Grand Master

scotty nm35

Posted
Posted

Sounds like AFM or boost cut. Both can show up at weird times as the turbo is much larger now, more airflow for the same boost. Definitely get it on a Consult3 and let us know. If there is no real error showing up, it could just need a tune as it's hitting parts of the map it was never supposed to.

Which highflow did you go for? It might be time for an Emanage...

YangLIU Rising Star

YangLIU

Posted
  • Author
Posted (edited)

Sounds like AFM or boost cut. Both can show up at weird times as the turbo is much larger now, more airflow for the same boost. Definitely get it on a Consult3 and let us know. If there is no real error showing up, it could just need a tune as it's hitting parts of the map it was never supposed to.

Which highflow did you go for? It might be time for an Emanage...

actually i got this GCG highflowed turbo from a mate, not quite sure how they highflowed it. GCG just told me both intake and exhaust end get highflowed.

i haven't got boost/AFM cut when hit 19-20PSI. my problem always happens when boost at around -5PSI or 8-10PSI.

i cleaned P0235 error code and lower the boost level a bit on EBC.

i saw the stock boost sensor is before throttle and boost sensor (for stock gauge) is at the end of manifold (after throttle). I connected my EBC with boost sensor (for stock gauge) together at the end of manifold. im thinking shall i move stock boost sensor to the end of manifold too with EBC together, because the boost level before throttle is a bit higher than manifold (after throttle)

post-137368-0-21147000-1440556687_thumb.jpg

Edited by YangLIU
scotty nm35 Grand Master

scotty nm35

Posted
Posted

Only the MAP sensor on the BOV pipe is causing the code, and it means the sensor is seeing 21psi or more. Looks like your gauge is out by a fair bit.

The cut will be AFM, it isn't just a voltage cut, it cuts at lower voltages depending on the cell it's in on the map at the time.

YangLIU Rising Star

YangLIU

Posted
  • Author
Posted (edited)

Only the MAP sensor on the BOV pipe is causing the code, and it means the sensor is seeing 21psi or more. Looks like your gauge is out by a fair bit.

The cut will be AFM, it isn't just a voltage cut, it cuts at lower voltages depending on the cell it's in on the map at the time.

from EBC, i never hit 21psi, so i assume move MAP to manifold could resolve P0235 issue?

for AFM cut, i need to scan with consult3 later

Edited by YangLIU
YangLIU Rising Star

YangLIU

Posted
  • Author
Posted (edited)

With a Highflow you should not really be trying for boost over 19psi on the standard injectors and fuel pump. When I had my 30/71r I only ever ran 17PSI.

just saying

sweet!

any idea for the boost/afm cut when cruise on motoway or 8-10psi boost.

Edited by YangLIU

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

    • Wazmond
      Stock rb25det neo questions

      By Wazmond · Posted

      Hows your intake piping? Are you still running stock? Having in the stock AFM position would mean, if the BOV was shut/venting out, it'd create the almost stalling kind of effect right // "the rich pulse behaviour" due to MAF thinking air is flowing ? But this would be better than having the bov in the stock position + MAF on/just before cross over piping right?
    • GTSBoy
      Stock rb25det neo questions

      By GTSBoy · Posted

      Essentially, yes. Although I wouldn't put the AFM on the crossover pipe. I'd want to put it into what amounts to the correct size tube, which is more easily done in the intercooler pipework. I bought a mount tube for card stile AFM that replaces the stock AFM - although being a cheap AliExpress knockoff, it had not flange and I had to make and weld my own. But it is the same length and diameter as the stock RB AFM, goes on my airbox, etc etc. I don't have a sick enough rig to warrant anything different, and the swap will take 5 minutes (when I finally get around to it and the injectors & the dyno tune).
    • Wazmond
      Stock rb25det neo questions

      By Wazmond · Posted

      So to summarise, the best thing to do is to move recirc to between turbo and IC, and maf on the crossover pipe. Meaning I'd need a recirc flange, drill a hole in the piping on turbo outlet area. And drill hole on crossover to fit/weld maf sensor? Either that or put the MAF on the turbo inlet right?  Is an aftermarket recirc/blowoff valve recommended? Do currently have family in Japan so could probably bring something back with maybe a cheeky lil SuperAutobacs run?
    • tsuokun
      Lets play a game - What is causing my oil consumption?

      By tsuokun · Posted

      Yep, so far most have said that it looks like corrosion on the wall from piston not moving. Which then has probably damaged the oil rings and caused those vertical marks. The longest the engine was still after the rebuild, was the winter of 2018 - 2019, plus the boat trip to Japan. When I shipped the car, it had normal gas in the tank but before that winter pause, it had E85 in tank.  In any case, even if either one of those was the cause, it happened close to 6 years ago and the car has been driven something like 30 000kms after the fact. Again, apart from the plugs and the dip stick, there is nothing in the way the car runs that would indicate what has been going on in the engine. I am going to consult a shop and ask their opinion, what would be the best approach. I do have some access to a garage I could use to diagnose further myself, but time is very restrictive. Might end up buying another engine that could be used while this one is being remedied. Without pulling the head, it will be impossible to find out if it needs another bore, but here's to hoping a hone would suffice.  Goddamnit, I would really have preferred this not happening.  
    • 25RBGT
      Got this r31 silhouette flood car to rebuild.

      By 25RBGT · Posted

      Boot is going to be replaced eventually. I just wire brushed what I could and rust converted. Then painted in rust kill primer. the spoiler also got repainted and plugs replaced on the ends. The under side of the bonnet is going to be black also, currently white. But red on the top side, same colour code as the silo to begin.
×
×
  • Create New...