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Fuel Cut When Cruise

YangLIU

By YangLIU,
in Four Door Family & Wagoneers

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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
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YangLIU Rising Star

YangLIU

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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

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  • 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

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