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Discussion Starter · #1 ·
Hey guys,


Sorry again for the seemingly funny questions.. hehe..

Anyhow, im using the Apexi PowerFC in my 34 GTR and when i gas it hard, like my throttle all the way down and the car is accelerating and i reach rpms of around 5500 onwards, the check engine light starts blinking all the way until i shift and it does it again from 5500rpms onwards in every gear if im going full throttle.

My mech claims that Nissan's and PowerFC's have this effect and it happens on his S15 as well...

Someone else mentioned that it might be injectors maxing out and the engine not having enough fuel...

But on my GTR tv thingy, the injectors show 99.7% and not yet 100%..

So is it true that this normally happens wiht PowerFC's or is something else up?

Also when i press the throttle fully to the ground, the tv console on the GTR only shows 90 - 91% on throttle. Never 100%.

Have never shown 100% before.. is something wrong with it?

Thanks again everyone!
 

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That's what your ECU does to tell you that it's reading knock (detonation) from the engine. 99.7% injector duty may as well read 110%. They're maxed out and you'll be killing your engine if you carry on IMHO.

Go to the boost setting on the Power FC and turn your boost down as a matter of urgency. Then find someone who can remap your car as mapping it to hit 99+% injector duty at 5,500rpm is just plain nuts.

Re. the throttle showing 90-91% - get someone to sit in the car watching the display, open your bonnet and go round to the engine and physically pull the throttle linkage as far round as it goes. You could find that your accelerator cable needs adjusting - could be that extra thick carpet you get on R34s is stopping your accelerator going all the way down ;)
 

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Discussion Starter · #3 ·
Jim27:

Thanks for your response bro.. The thing is, the car was tuned by Eiichiro of Autoselect Japan and he'll only be back here sometime next month.

They were saying that the knock sensor on the PowerFC is really sensitive and sometimes the engine isnt really detonating and the PowerFC will still show that it is.

No no.. I wasnt saying that the injector duty is 99.7% at 5500rpms.. What i meant was after giving it full throttle and hard for gears 1 2 and 3, i find my peak injector duty to be 99.7 and not yet 100% so im assuming thats ok?

Thanks alot for the responses..
 

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Still not ok, injector duty should never go about about 80% as far as i believe. I'm sure someone else can confirm?
 

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Discussion Starter · #5 ·
D4T: Im doing around 99.7% - 99.8% injector duty at full throttle..

I was assuming its ok cause the injector duty never reached 100%..

Im not sure how much power im making but the specs of the car are as follows: (Just engine mods)


-Nismo Intank Fuel Pump
-APEXi GT Spec Intercooler
-Trust Oil Cooler
-APEXi PowerFC
-Twin SSQV BOV's
-Twin HKS Pod Filters
-Autoselect Lenght Tuned Front Pipes
-Blitz Nur Spec exhaust (pipes are 100mm or 110mm i think)
-HKS EVC4 Boost Controller
-SARD Oil Catch Can
-HKS GDMAX III Twin Plate Clutch

Thats about it i think..

Standard turbo's boosting 0.9bar for low boost and 1.2bar for high boost.

At low boost, in certain gears only will the check-engine-light blink under high rev's and by high im meaning like 5500rpms - 7000rpms.

At high boost, almost thru every gear at 5500rpms - 7000rpms it blinks and only when full throttle..

My car was road tuned so i dont know the power output but a few people/tuner estimates it to be around 400whp..

Is there something wrong with my car?

Thanks alot in advance for the responses.

Appreciate it as im clueless now... Hehe.. Thanks again
 

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Your duty cycle is to high, 90% max to preserve the injectors and to ensure the AFR you are asking for is being achieved.

Blinking engine check light IS A VERY BAD THING. The PFC is showing you that the knock reading from the sensor is higher than the threshold setting. IF the setting has not been changed from standard (60) you are most likely doing engine damage everytime you use full throttle.
 

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The check engine light flashing may have nothing to do with det, it may just be warning you that the injectors are exceeding the duty cycle threshold set in the PFC. You will need to make a note of the sequence of flashes as this will tell you what it is warning you about... Either way, the duty cycle is definitely far too high.

Have you set the PFC for peak hold values? if so, you will be able to check what det. levels you've been getting.
 

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Discussion Starter · #9 ·
So meaning the tuning is running far to aggresively and should be tuned down a tad?

How do i check the PFC peak hold values and also how to check what det. levels ive been getting?

Thanks again guys

Really appreciate it
 

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To get peak hold on go into 'Monitor' and select the sensors you want to view then when they are on the screen press 'up' and the maximum value will be displayed / stored.

Go to 'etc' then 'function select' and see if 'injector / airflow warn' is on. You'll have to figure out which symbol means 'on' from the others as i can't write it on here! If you switch it off and then the light stops flashing then it was warning you about the injector duty which is still a problem but not as bad as if it still flashes and is knock!

In any case turn your boost down and take it easy until you get a tuner to look at it!
 

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Yes they are - i think the default is 0.1s for knock and 0.5s for inj duty but i wouldn't much like to be trying to see which it's doing at full boost and 6000rpm!
 

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if you carry on like this, with that light blinking, you WILL blow up your engine. How do I know? I just got mine back after a four-month rebuild and $7000+ USD....
 

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Yes they are - i think the default is 0.1s for knock and 0.5s for inj duty but i wouldn't much like to be trying to see which it's doing at full boost and 6000rpm!
Yep, had a look at the manual and it says 3x0.1s for knock, continuous .5s flashes when injectors are maxed.
 

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I'm starting to have the same problem. Iv got 800cc injectors so I can't really see them maxing out. The car ran fine for about 4 months after being tuned and now it's doing what the other guys doing
 
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