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Discussion Starter #1
hi

stockish GTR, jap chip

AFR seems to be really high at idle and part throttle, i have seen 12.0/1 at idle and worse on rundown

can someone just confirm that AFR is 14.5 at idle on a well running GTR when warm?, it seems to warm up right from cold.......AFR 15.0/1 but when its warm this just seems to go mega rich

lambdas need replacing maybe or they could even be disconnected from the ECU?, would this throw a code up?

regards, brian
 

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Discussion Starter #3
yes i know that

its the 12.0 at idle that concerns me not the 15.0/1 during warmup because the rich condition causes borewash
 

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As a reference, my car
Idles @ 13:1
On cruise its 14.7:1
WOT its 11.5:1


Usually cars should idle and cruise @ 14.7:1
 

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Discussion Starter #5 (Edited)
As a reference, my car
Idles @ 13:1
On cruise its 14.7:1
WOT its 11.5:1


Usually cars should idle and cruise @ 14.7:1
thanks mate!!!

mine is also off the scale rich lower than 10.0:1 at WOT

it does not use the lambda sensor at WOT though so why should it be so rich compared to yours?, i take it yours is stock or chipped ECU and not a remapped PFC or the like? (which we may expect to see leaner conditions on?)

Idles @ 12:1
On cruise its 11:1
WOT its <10:1
 

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My ECU is programmable, hence me being able to chose the AFR's I like.

It sounds like your fuel pressure regulator has been moddod. Does it look like the top has been pushed in?(to alter the spring rate)
 

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What setup are you using? Injectors, ECU, FPR etc..
 

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Discussion Starter #8


looks stock, the fuel pressure at idle is 3.5bar..

ECU is a nissan remanufactured ECU with a STORM chip ("tokyo power base" it says..)

injectors "look" stock?

i rebuilt it but i know nothing about the engine management side, thanks for helping!
 

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What setup are you using? Injectors, ECU, FPR etc..
I'm guessing your ECU uses wideband lambdas, therefore making your AFR readings reliable? I'm mulling over this particular issue now - I want wideband accuracy in my car, but I don't think the Apexi Power FC supports it (not sure on that), plus I'd like to drive an A/F meter with a wideband...meaning I might have to add a bung or two to my downpipes...?
 

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Discussion Starter #11
i use the stock lambdas for the ECU and a wideband for a readout that does not go to the ECU (just displays the infomation in the cabin)

my AEM wideband has a facility to output the voltage to the ECU in narrowband format but this would only be one sensor for both banks and i assume the ECU can correct just bank one if need be, my wideband would give an average for both cylinders which would be a disadvantage?

(i have one at the sensor just before the cat, ebay do cheap bungs)

i guess for best results you would use two widebands but this would be expensive and TBH i have so many gauges now i cant look at them all lol
 

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With the PFC datalogit, you can log AFR, but the ECU won't do anything with it.
 

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Discussion Starter #13
so can someone confirm that fuel pressure as stock is 3.5 bar at idle please?
 

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Yes, I think its close. Mine is set to 48psi, which is 3.3bar. 3.5bar is 50psi.

I think STD is 48psi
 

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Discussion Starter #18
it seems that the car isnt going into closed loop, disconnecting the lambda sensors results in no change to the fuelling

ECU loom looks like it has a few spliced conections on it from a piggy back ECU that was once fitted and then removed, may just be a misplaced wire hopefully
 

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3bar standard pressure....

With vacumn off.

Rob
 

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Discussion Starter #20
i had a look at the wires going to the ECU..there was no voltage present at the ECU clip from the lambdas (pin 29/55)

i have a AEM wideband that can output a narrowband sigina lso i tried feeding this to those pins but there didnt seem to be any effect to fuelling

i guess this looks like an ECU fault?
 
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