RB25DET engine with Z32 ECU need help !

[ar99kid]

long story short :

1. nissan skyline r33 , engine rb25det fully forged with Z32 ecu , 630cc injectors , q45 90mm maf , plus a lot of mods but don't meter here...

2. oem ecu (rb25det) #21U01 , Z32 ecu #31P02

3. i have ordered the type 2 board from RSP in UK . ( very bad experience , allmost 1 month of waiting for the board and payed DHL express shipping 3 days because i was in a big hurry ....NEVER RECOMEND THIS DEALER !!! i was too stupid because i should have order directly from here , but being over time i thought it would be better to buy it from UK to take sorter time...big mistake , 4 weeks ...

4. problem : i am not able to make this engine run on idle ! dies when let the gas

5. here is what i have done , tried a lot of configurations:

a. load adr. file Z32_256 , open bin file coresponding to my Z32 ecu. firs adjusted for 630 injectors , then for q45 maf , included tp adjustments , played with k value , etc...dindn't work. tried again without changing the tp's only k ...didn't work either...

b. load adr for type 2 from "misc" folder Z32_256_for_rb25det , did same things like above , didn't work ...

c. played with idle target rpm , rised the o2 temp value to max ,tried a lot of thongs , but no luck ... the engine starts great , when hit the throttle works great but when i let of the gas it comes down to 400rpm ( tps is on , red) but goes in some sort of limp , very rich ! if i let of the gas slowly it will hang 1300rpm and stay between 1100rpm and 1400rpm

here are two logs ...

if i 've done nothing wrong with adr. file and bin files , i was thinking maybe the board is not programed correctly to run the rb25det ? is that possible ? i was asking this type 2 board for z32ecu runing rb25det engine ...but because of the bad experience with risingsunperformance , i don't know what to belive anymore...

need desperate help !!! 3 days now and tried everything i could think of ...i am not a "hex" guy so don't really understand how ecu works , but i have pretty much experience of working with ecu , piggybacks and standalones. i have buid this car for races , and next weekend starts the championship and from waiting so long for the board i am up to my neck in time problem...

[louiswun]

In the fuel map tracing, did you see the loading goes high (the right hand side) when let off the gas padel, when the rev droping ?

[ar99kid]

yes , exactly ! do you have any ideea ? was thinking of that , but can't understand why...and is going very rich , i can see black smoke coming from the muffler also the AFR is out of scale !

want to mention that i have cleaned the AAV valve , HKS blow off is adjusted to max and also tried to block the exit of it to be shure that i don't have vacuum leaks

here is the bin i am running now , with this one is more stable but keeps hunting idle 1000-1400rpm and dies when let of gas or
in traffic when changing gears . the only way no to die is to slow down in gear untill 1800-2000 and then press the clutch to brake ... really difficult all the time

thanks for looking

[skylinegtrhr]

So car never can idle or only after You release gas pedal?
Do You have situation like this ?
viewtopic.php?f=11&t=1879

[ar99kid]

thanks for that link ! exactly same problem here ... but i do have 90* elbow 4" diam and in total lenght about 20" so it should be enough air volume there ... i will try with a plastic pipe to see if changes something

[Eric]

what kind of fuelpressure regulator are you using ? and have you verified the pressure is correct ?

Although it's hard to tell from the picture, it looks a bit like you're using a rising rate FPR ?

[Matt]

Problems noted with attached BIN
- Q45 MAF in your post above but this has Z32 MAF

That will cause issues with bad load readings due to incorrect calibration table used

Injector time is going very lean a lot then affecting AFRs

[ar99kid]

thanks for everybody's input here !

matt , i have tried both z32 maf table and q45 maf table and seems to work better with z32 , that's why that table in the bin. thanks for the new bin , will try it out today ! so from what i understand it is better to use that z32bin for rb25 than the z32 bin , right ? regarding the new k value from your bin it is 161 . i have put all the fuel table at stoich , disconnected the o2 , and run the car with no load (parked) and also driving in low load and i've got to a 180 k value being closer to the afrs needed. so is it ok to run with 180 k ? i have the most agresive porting possible on the head but still oem cams and 3 bar fuel pressure idle , could this thing influence the k so much ?

eric, yes i have a rising rate fpr . it is on 3 bar idle and going up with the boost by 1.7:1 ratio. i wanted this setup because i will keep this car for city driving also and didn't want to mess with very big injectors . for the power levels that i want i have a high volume / high pressure fuel pump and can flow up to 300lph at 5bar which is more than enough for 550-600whp .

so far i have made some progress ( helped by skylingtr thanks ! ) i have focused on the maf setup and one thing that i have noticed : didn't tried the extension on the maf with a longer pipe yet , but i have a very big compressor ( garrett bb turbo t04zr capable of over 680hp ) and because of this my HKS bov setup is too small . i have a great amount of air surging the turbo at only 5psi and i was thinking that this issue will affect also on small rpms and low load and it did !!! i have disconnected one hose (the one going to the idle control valve) and when let the throttle off was blowing outside, a lot of air !!! this thing helped very much my idle , doesn't die at all ! so i will improve the setup with two recirculation valves between the compressor pressure pipe and the compressor intake and still keep the bov . will let you know how it works !

thanks all for watching !

[skylinegtrhr]

and because of this my HKS bov setup is too small

Yes we also have to run two BOV's (other is on "cold pipe" so it is not on picture I post) as one was giving problems and revers flow was affecting AFM, seams to me that we all have to make same route for finding solution for big turbos setup.
We are now considering one big Turbosmart or HKS racing BOV or maybe new type Synchronic BOV

[Eric]

>yes i have a rising rate fpr . it is on 3 bar idle and going up with the boost by 1.7:1 ratio.

keep in mind it's very hard to tune a car with a rising rate regulator, this because the fuel pressure (and injector flow) will be all over the place.
In my opinion you don't really need it with the 630cc injectors, which should be fine up to approx. 600 hp with a normal FPR.
If your goal is 550-600 whp you should first find another AFM, because a Z32 or Q45 FM will not read over 500 whp.
For fuel you could increase the overall fuel pressure to 4 bar or consider 680cc or 740cc injectors...the RB25/26 should still idle fine with those.

[ar99kid]

eric, i know the q45 maf is going for 500 , but i still can alter the maf table so for a given voltage to "messure" less air , right ? and still play with the tp scalers so when i hit 1.6 bar ( i think that will be close to my target ) to be in the last two columns . this is my thinking ... that will be in the future , right now i am working on that f*** idle problem and make another BOV work like a diverter !

thanks for the input !

[ar99kid]

so far i have made this , see the pictures and seems to work much better
now. still dies when coming from 4000rpms but up to that point of rpms comes
down prety good and keeps the idle after a little bit of hunting. will do
again a boost leak test to see if there is something else coming up and will
let it be for the moment.

i have drive some power runs on the street and after working a little bit o the maps i've got some pretty good results ....seems that when coming into boost i am bearly keeping the car on the street in the 3rd gear , very happy !

BUT there is a problem thet is strange to me : 1st , 2nd and 3rd gears are running great , i can map them perfectly in the main fuel map . when i change the 4th gear the ecu is reading some other map !!! very rich !!! even if i try to lean the main map is only changing 1,2,3 and the 4th is still rich . please see the .bin file that i am running and also the log ...

for matt : is it possible that the knocking fuel map is used by the ecu to run 4th and 5th gears ? i have set all knock fuel map to 10 AFR ...

please let me know , thanks !

[ar99kid]

didn't let me put more than 3 attch so here are the bin and the log.

at the begging of the log are the gears changing 2nd , 3rd and 4th . on the 3rd about in the middle of it there is a low tps for a moment because the car started to go sideways and i had to let the gas a little . please look at the 4th afr and you will see how rich they go

any input is very welcome , thanks !

[Eric]

the Z32 ECU has a special high gear fuelmap.

there are a few topics on here how it works and how to disable it if needed (set high gear coefficent to 0)

[ar99kid]

thanks eric !

i was very tired last night... started fresh this mornig and did find the high gear fuel map , but only after i have reloaded the adr file. when burn it to the ecu worked fine, after read it from ecu seems to not load that fuel map...strange. does it need all the time to load the adr file ?