CA18DET JDM ECU 4 pin AFM, idle with or without O2 signal

[louiswun]

Enigne:JDM 8 port CA18DET
ECU: JDM ECU 23710-36FXX
Chassis Harness: Original Euro S13 200SX, 4 pins AFM plug, no O2 sensor plug, no CAT temp sensor
AFM: Original 4 pins CA18 AFM but now swap to Z32 AFM
Injecors: used to be GTR stock 444cc but now swap to GTR35 Denso hi impedance 620cc

My old set up is JDM ECU + JDM CA18DET + 444cc + CA18DET stock 4 pin AFM
But after I have changed to Z32 AFM + 620cc injectors, I have found that I cannot get the idle spot on 14.7 AFR.
I have tried ......
left the AFM 4th pin (green wire with yellow strip) unconnected or
direct connect the 4th pin to the AFM ground wire
connect a 4K ohm resistor between the AFM ground and the 4th pin
connect a 2k ohm variable resistor between the AFM ground and the 4th pin
connect a 500 ohm variable resistor between the AFM ground and the 4th pin
connect a 200 ohm variable resistor between the AFM ground and the 4th pin
No matter how I did to the 4th pin, the idle mixture did not affected
No matter how I change the K value + latency combination, If the AFR when partial throttle without loading is correct (ie: between 14 to 15), the idle mixture is always 11.X to 12.X
I have tried 3 JDM ECU, same.
I have tried to load 36F00 and 36F05 bin file, same.

When I was so furstrated on the idle, I try to feed the simulated narrowband output (from my wideband) to the ECU.
And I have found that if no O2 sensor signal connected, the idle always rich, Nistune showing 0.3X voltage on O2 signal.
If the O2 sensor signal is present, the idle will pull down to 14.X and Nistune showing the real O2 signal.
But the mixture still rich after I hit the throttle to free rev my engine, but it will finally pull down to 14.X
I have a switch between the simulated narrowband output to my ECU,
This video is showing with or without O2 signal and how's my idle mixture goes.
http://www.youtube.com/watch?v=2ZaAWK9Aoow

I always thought JDM ecu did not requir O2 sensor as I've been running my enigne without O2 sensor since 2006.
But now I belive it require O2 sensor, otherwise it will be too rich on idle.

Seems like I have the same situation with KillerB
viewtopic.php?f=7&t=1427

and skylinegtrhr DENSO EVO9 injectors on CA
viewtopic.php?f=12&t=1901

[skylinegtrhr]

and skylinegtrhr DENSO EVO9 injectors on CA
viewtopic.php?f=12&t=1901

Yes but our EDM S13 was with O2 sensor and 3 pin AFM so problem was definitely with injector setup. (also we couldn't make it to idle stoic , only if we get latency to some crazy numbers but then car was not drivable at all)
On B13 EDM SR20DE which don't have O2 and have 4 pins AFM , when we try to not connect for pin we could make good idle but car time to time become very rich and start to stumble, but when we put exactly the same resistor as was OEM AFM there is no problem.

Try to isolate problem by putting 4 pins AFM or JECS injectors on car.

My only idea was that DENSO injectors should use different resistor pack but values are same for EVO9 and S13 CA (s13 CA pack should be 6 Ω and injectors 2-3 Ω, EVO 9 5.8 − 6.2 Ω and injectors 2-3 Ω and R35 is driving injectors straight from ECU so no resistor pack injectors value is 11.1 - 14.5 Ω) ) but never experiment with it...

[louiswun]

and skylinegtrhr DENSO EVO9 injectors on CA
viewtopic.php?f=12&t=1901

I know that the R35 injectors is high impedance, and I know that it does not require the resistor to control the current draw, I had bypass the resistor before starting the engine, and all 4 injectors are received full power.
This problem was not on the injector / resistor combination.
On RB20 and RB25 engine, I have tried 5Ω and 6.8Ω resistor with low impandence injectors, the only different I could found is the injector's lag time (lantency).

After got a hint from Matt, I tried to adjust the VQ map and now my idle can adjust to stoic,
On SR and RB ECU, the VQ Map is 64 point and matched the Z32 stcok VQ Map, using Z32 AFM on those ECU will not see this problem, or the different is so small and easy to adjust accroding to the mV it shows in nistune software (VQ Map tracing).
But on CA ECU, the VQ Map is 56 point and the map tracing is off scale.
Now, my K value and lantency is rougthly adjusted,
I have to find which load point my ECU is reading from, after adjust the first 6 point of 56 point, my idle is close to stoic. If the K value and lantency changed, the VQ map also need to change to suit the K value/ lantency combination.
I think when my engine is on boost, after final adjusted the K value and lantency, I will need to re-adjust the VQ map again.

I have found another problem,
my ECU is showing code 55 (No Fault) on mode 3 self diagnosis,
but my ECU only respone in the knock fuel map and knock ignition map,
The actual AFR and ignition timing is 100% following what I have in my knock maps.
It did not response on the main maps.
And the TPS idle timing is only showing 10 instead of 15.
There might be something wrong to force my ECU using knock maps.

PS: my engine harness is EDM S13 AT, but swap to MT gear box.
The gear switch is not connected.

[skylinegtrhr]

After got a hint from Matt, I tried to adjust the VQ map and now my idle can adjust to stoic,
On SR and RB ECU, the VQ Map is 64 point and matched the Z32 stcok VQ Map, using Z32 AFM on those ECU will not see this problem, or the different is so small and easy to adjust accroding to the mV it shows in nistune software (VQ Map tracing).
But on CA ECU, the VQ Map is 56 point and the map tracing is off scale.
Now, my K value and lantency is rougthly adjusted,
I have to find which load point my ECU is reading from, after adjust the first 6 point of 56 point, my idle is close to stoic. If the K value and lantency changed, the VQ map also need to change to suit the K value/ lantency combination.
I think when my engine is on boost, after final adjusted the K value and lantency, I will need to re-adjust the VQ map again.

When You finish with VQ map modification can You please post that map?

[Matt]

With CA18 the ignition maps (knock/main) are not actually knock. Yes need to update the software to reflect this Nissan 'special' change specifcally for this ECU to call it timing average1 and average2 perhaps?

The timing map cells selected get added together and then divided so effectively there is an average. Should be regardless of knock or not (pretty sure I was looking at 36Fxx JDM ECU here at the time)

With fuel using knock maps without KNOCK SENSOR DTC code is interesting. What if you try and put 500 Kohm resistor on both knock sensor inputs. Perhaps its not getting a fault code, but still picking up knock during normal operation and starts using maps straight away?

[louiswun]

When You finish with VQ map modification can You please post that map?

I'm not sure if it is correct or not, PM sent already.
Might require further adjustment due to round up error, please check.
(error example : In the Z32 VQ Map on CA18 ECU column, the 1595mV should be the same cell on 1600mV, but on my excel file 1595mV will lookup as 1520mV )

[louiswun]

With CA18 the ignition maps (knock/main) are not actually knock. Yes need to update the software to reflect this Nissan 'special' change specifcally for this ECU to call it timing average1 and average2 perhaps?

The timing map cells selected get added together and then divided so effectively there is an average. Should be regardless of knock or not (pretty sure I was looking at 36Fxx JDM ECU here at the time)

With fuel using knock maps without KNOCK SENSOR DTC code is interesting. What if you try and put 500 Kohm resistor on both knock sensor inputs. Perhaps its not getting a fault code, but still picking up knock during normal operation and starts using maps straight away?

Both knock sensor ?
I only see 1 knock sensor on my block,
do you mean I have a faulty knock sensor and try to unplug the knock sensor and replace by 500Kohm resistor ?
I have test the fueling and timing between idle and 2,000 rpm no load reving.
After asjusted the VQ map, the ignition timing showing in nistune and Apexi multi checker is exactlly the same on my kncok timing map,
The AFR is following what I have entered on my knock fuel map, I have tested from 16 to 12 AFR.
I also tried to do changes on the main fuel map and ignition map, but AFR and the timing read out did not affected.

[louiswun]

I have just found that my excel file is incorrect, it should be 52 point instead of 56 point.

[Matt]

Both knock sensor ? I only see 1 knock sensor on my block,

Okay must be CA18 1 sensor and HCR32 2 sensor. I have two wired in on my bench but take twin sensors.

do you mean I have a faulty knock sensor and try to unplug the knock sensor and replace by 500Kohm resistor ?

If you are getting Knock Sensor DTC code then this is advised. Otherwise it will use the knock fuel maps with DTC enabled

The AFR is following what I have entered on my knock fuel map, I have tested from 16 to 12 AFR. I also tried to do changes on the main fuel map and ignition map, but AFR and the timing read out did not affected.

Are you getting knock sensing DTC. Perhaps ignores the primary map during this. Normally it uses average of both timing maps when no knocking issues

[louiswun]

Hi Matt,
I do not have any DTC code on consult display.
I have tried to unplug AFM while the engine is runing, after that, there is AFM DCT code.
Could you check what function is the bit 7 in CA18 feedback switch ?
When bit 7 is ticked, the idle AFR is around 13.2
When bit 7 without ticked, the idle AFR is around 14.7
It is feels like bit 7 is a switch, a switch to control idle mixture
It is feels like when bit 7 ticked, it ignore AFM voltage on idle, idle mixture is control by O2 signal,
and this time I did not feed the simulated narrowband output to my ECU, the default lean signal 0.32V is showing in consult disply, may be due to this reason it give more fuel for idle.
Or it is a AFM trigger voltage (low voltage trigger)

This bit 7 AFR checking is done after I have confirm my K value + latency is spot on.
Also, my 52 point VQ map is adjusted the first 8 point, nothing changed the 9th point and any after.
Actually, the first cell, no matter what number I have input , the ECU will never access.
now I can have almost flat 14.7 AFR from idle to 5,000 rpm engine no load free rev,

This is how I adjust my VQ map
Unplug the idle switch to force ECU access timing map instead of idle timing (idle timing will change with different engine rev)
unplug the AAC valve and adjust the idle screw to force the engine rev as low as it can
adjust all low load area in the timing map to 15 degree (filtered value)
adjust all Accel Increase Fuel to 0
adjust all Min TPluse width to 0
adjust all Max TPluse width to 255
disconnect fuel pressure regulator vaccume hose to fix the fuel pressure (0 vaccume and 0 boost), pluged the vaccume hose to advoid vaccume leak.
adjust 1 single VQ point at a time, put a lower number in that point, slowly increase the engine rev, keep watching the AFM output voltage, when AFR goes leanest, hold the AFM voltage by throttle and increase that VQ point until AFR is 14.7

This is the first 8 point I have now in my VQ map
300(or whatever, didn't access)
400
530
708
847
1036
1203
1475

with disconnected fuel pressure regulator vaccume hose, AFR is 14.7 anywhere between 600rpm to 5,000rpm no load free rev
With connected vaccume hose, AFR is around 15.2


After adjust all map to normal numbers, plug back idle switch and AAC, adjust the idle screw to normal idle rev, reconnect vaccume hose, I went for road test, and now it behave like SR and RB ecu. But it still have injector switch to batch injection lean spot.
I think the bit 7 is not related to Idle switch, by the time I'm adjusting the VQ map with idle switch unpluged,

when AFM voltage anywhere lower than 1.2v, mixture will go rich, if I lower the VQ map's 2nd point to achive 14.7 AFR idle, when slightly open the throttle, it will have a lean spot between 2nd point and 3 point (2nd point is where my idle accessing, AFM voltage lowewr than 1.2v, 3rd point is slightly more than 1.2v).

When bit 7 is unchecked the tick, I can see my 2nd point number is too low, after adjusting, the transistion between 2nd and 3rd point is perfect smooth 14.7 without lean spot, thus it make me think that bit 7 is switch for any lower than 1.2v AFM voltage switch to control idle mixture by O2 signal.

Matt, if VQ map tracing is refere to mV, is that possible to change the CA18 VQ map mV ? I have found that my calculation in the excel file is very close to where my ECU accessing.

[foofers]

Bringing this back to life...
Using nistune is there a way to get around the lean issue when the injectors switch to batch fire mode for the ca18det.

I'm using a z32 maf and 650cc injectors.

[louiswun]

Bringing this back to life...
Using nistune is there a way to get around the lean issue when the injectors switch to batch fire mode for the ca18det.

I'm using a z32 maf and 650cc injectors.

Replied, please check PM.

[ricardomendes]

do you have confirmed the bit 7 is related to lower maf voltage?

regards

[louiswun]

do you have confirmed the bit 7 is related to lower maf voltage?

regards

No, I don't think so ! Not sure

[Matt]

I dont see a refernce to #$80 (bit 7) in ecu code 36F05 (but defined as #$A0 = #80 + $20 bits)

This is set in MT BIN #$80 and disabled in AT BIN #$20 so used for AT system