Z31 non turbo ecu with turbo idle controls

[bsdkllr]

The factory service manual is a bit hazy on how the 2 idle controls operate. but im not sure if my problem is related to the turbo idle controls. or the lack of the auto trans that used to be in here.

during warm-up i get idle speed hunting where it drops down to about 500 and pops back up to 1000 rpm. once warmed up it idles perfect at about 650-700rpm. (This could be related to bigger injectors and possibly K value being off)

also the second issue. is im not getting a speed signal to the ecu. I have the factory turbo wiring harness but it always shows 0 unless speed signal is disabled then it shows 38. (Does the non turbo ecu not have this circuit?)

and then finally can i swap the Nistune hardware over to a turbo ecu? or would it need programming? it does currently read out as a turbo ecu in Nistune now.

Thanks

[Matt]

Auto trans ECUs adjust idle differently for the torque converter. If you changed to manual, it may operate differently. Depends when the problem started (after the trans swap) or otherwise

Speed signal comes from the dash cluster as a PWM input, and gets its signal via hall effect sensor in the transmission. Something not right, but outside the scope of Nistune technical support. See an auto electrician with your wiring

If you install Type 1 into a turbo ECU then make sure it has 26P00 or 26P0F (Feature pack) firwmare loaded. No idea what you have loaded on it at the moment, connect to software to get the current ECU ID

[bsdkllr]

This was a na2t swap using a no turbo block. I swapped the auto turbo wiring into it. And luckily I'm the electronics guy. I was just curious if you had seen any difference in the na ecu or t ecu. I'm thinking the na ecu does not have the speed signal circuitry. But I will check that code. I do remember when I ordered it you asked if it was a turbo. And programed it for that.

[Matt]

There should be no difference between NA and turbo hardware, apart from the knock sensor board

[bsdkllr]

I just noticed that i forgot to mention it is an 1986 model with same year ecu.

and also i have noticed that the rom image listed for Z31_VG30ET_1986_19P03_MT.bin is the same as Z31_VG30E_1986_18P03_MT.bin and i suspect that is in error.

[bsdkllr]

What do i have to do to get the TIM feature? i dont seem to have that option. im currently having a hell of a time getting it idling good. its all stock except its a na block and euro/nismo cams. and merc 036 injectors (420cc?)

[wilsonthesphere]

What do i have to do to get the TIM feature? i dont seem to have that option. im currently having a hell of a time getting it idling good. its all stock except its a na block and euro/nismo cams. and merc 036 injectors (420cc?)

You will have to the firmware updated on your board. I had Houston Z Auto upgrade my type 1 board. That did it the same day and sent it back. I really recommend those guys.

The separate TIM and K constant made it so much easy to get the fueling right especially with really big injectors.

[bsdkllr]

if i ordered a new nistune board im guessing it would come with the new firmware?

and would a k value of 260 and a latency of 1250 sound off for suspected 420cc injectors?
i cant get great info about them but people say anywhere between 380cc and 495cc.

i'm getting pretty close to putting the stock ones back in.

[Matt]

Z31_VG30ET_1986_19P03_MT.bin

This is an error from the looks of things. Fuel map was slightly different to 18P03 but is a non turbo ROM image. I'll remove this from the ROM pack for next release

You need feature pack flashed into the board to get the TIM parameter. This is only available in the 26P0F firmware. It can be programmed into other model turbo Z31 ECU boards

If you order a new board, make sure you request 26P0F

1250 is to high for 420CC injectors, about 700uS would be more reasonable

[bsdkllr]

Im starting to think the 86 ecu is a bit garbage. are you saying the tim firmware is available on different z31 ecu's and not the 86?

im not sure what im doing wrong but i just cant get this running right. the full range from 700 rpm to 3200 rpm is most times a mess.if i cruise on the highway i can nail the ltft right around 0 but once i go to an idle it just wants to die and buck and spit. i have tried all sorts of things. if i get it idling moderately good it will pin the fuel trims right to -25. i have tried using the injector resize function. As all i have done is put euro style cams on a na block with all of the stock turbo parts and ~420cc injectors (maybe 480cc. info is a but confusing.they are 75 Mercedes 450 sel injectors)

also i have a few 86 ecu's one being a turbo automatic one. and that one does have additional resistors and components inside. and im wondering if thats for the speed input and idle controls?

im wondering if i should source a different year ecu? or just put the stock 260cc injectors back. i dont think im pushing anything that far. i dont have any plans to raise the boost or anything outrageous. maybe 1 or 2 more psi. hopefully i will have my exhaust soon so i can use my wideband to assist in issues.

[bsdkllr]

Just wanted to update that i sorta have it working better. i have disabled the O2 for now and built a new map based off of some others out there.

im going to need to drive around and see if i can get the fuel trims back to 0 and see if my low end breakups go away. i have noticed if you mess with the sequential mode switch it can mess around with fueling on idle. should this box be ticked or un ticked.

Im going to further investigate the aac valve as it seems to not be working correctly. if i enable or disable vehicle speed input the idle will sometimes get stuck at a high 1200 rpm idle. and if i unplug it it returns to normal. i will try and scope it out but yesterday i was getting a sawtooth wave. but i may have been getting interference with that scope.

[Matt]

are you saying the tim firmware is available on different z31 ecu's and not the 86?

Only developed using 26P00 firmware. From what I can tell, can be used in other 1986-1989 Z31 ECUs without issue

but once i go to an idle it just wants to die and buck and spit.

look at logs to work out why, is it going too rich/lean. Need a log file with the tune to replay and see the issue

also i have a few 86 ecu's one being a turbo automatic one. and that one does have additional resistors and components inside. and im wondering if thats for the speed input and idle controls?

Unsure. There is no schematics for these ECU hardware

you could try the 260CC injectors back in if nothing else works. Try and figure when the problem started, and what was changed at that point

[bsdkllr]

i just want to make sure im doing this right.

what should i be selecting for my vehicle? the 86 address file or the 88-89?
if i select the 86 and then load the 26p00 firmware the scales are all over the place.

Should and can i load a feature pack address file?

and the problem started with the injectors i believe. everything was running great until the turbo stuff was swapped over to the new engine. right now it seems to have the same hesitation that the stock ecu na has. and im wondering if im just chasing nothing. but i would love to get the full capability out of nistune.

and thanks for your help so far. im a bit busy with projects and im a frazzled mess.

[Matt]

You must use the address file matching your image. Nistune will pick this up from the ECU part number

so if it is FP with 26P0F it will load the 1988 FP address file

If it is 1986 part number, it will load that instead

IF the wrong address file is loaded then maps will not be displayed properly

[bsdkllr]

Thanks for the help Matt. i think im just going to put my stock injectors back in and call it a day. im not sure whats going on but something is not right. im starting to think these injectors are just not good. this is a stock motor so i dont think im ever going to need bigger injectors.