Z31 Feature pack issues

[cmbz31]

I have the feature pack z31 88 software uploaded on my ecu. Ive been trying to get it up and running the TIM is way up almost 900 just to get it running to idle. i have 440 RC injectors with a hpx n1 MAF sensor i recalibrated the injector sizing and did the MAF VQ scaling at 73 percent. I Currently have the Injectors Wired for Sequential mode .It idles fine for about 1 min then over fuels to the point where it floods and shuts off. the short term fuel trim goes to like 15percent....???
My first question is if i need to wire it back to batch mode wiring...???
Also if 72 percent is way to much for the VQ to register correctly??? Im currently running in a 3in tube.
Also Not currently running a o2 sensor do i need to run o2 In order for the fuel trim to be correct..???

[Matt]

Several things... too many things done at once, so you need to go back to basics

If you are questioning your wiring, then make sure you fix this up _before_ changing injectors and MAF. Otherwise it makes the situation even more difficult.

I cannot comment on the Z31 wiring since there was some Nissan update which swaped them around, but I'm not sure on the details

Once you have that sorted, then try getting the car running with factory MAF and only the 440CC injectors. Then do the injector resize from factory to 440CC and adjust latency around 700uS and then check that is running okay. Adjusting this will only change TIM (from default 512) to a lower value

So once that is all happy, then finally change to HPX MAF. So do the voltage drop mod inside the ECU (ref Type 1 manual end section) and fit the MAF. Make sure it shows valid voltage in Nistune (and increases when you blow through it). After this then do the Operations > change MAF and if in 3" tube select HPX N-1 3" tube (Z32 load)

After this you may need to tweak the bottom end of VQ map for idle, and also adjust the K constant/TIM so you have stocih mixtures at cruise, and full map access when going on boost

[cmbz31]

OK so since it was a fresh rebuild there was a couple issues with my setup. I put stock injectors back in and a stock MAF to check the operartion of the engine with original equipment . Ended up bieng that the Distributor was off a tooth throwing everything into a big loop. Im gonna run it stock to break in my engine.Once i get my engine broken in i will swap the 440cc injectors back in along with the stock MAF. ....
My main concern here is that my ECU is a 88 year model witch uses supposedly high impeadance Injector drivers.. When Nistune was installed was there any mods to the Injector drivers to run high and low impeadance injectors.???

Thanks Matt I apprieciate your insite...

[Matt]

The injector driver impendance is a hardware configuration item inside the ECU. There is no firmware control (so Nistune cannot change this)

The 1988 model uses high impedance injectors (12ohm) rather than low impedance (about 4ohm) of the earlier models. You can run high or low impedance injectors then with this ECU

[cmbz31]

SO i ended up getting my car running pretty good the main issue i was having is that the HPxn1 MAF sensor is a different voltage compared to stock so with the Nistune ECU i am only able to run the HPxn1 sensor. With that out of the way car runs really well at operating temps pulled good and at full boost stays around 11 to 1 afrs. At cold start it is really lean maybe 16 to 1 even goes into 17 to 1 i need some input on correcting this issue as it makes it hard to drive and will even stall out at cold starts. I had messed with the crank enrich tabels and the enrich after start and still no progress. What do you think i should be focusing on to resolve this issue? if i turn the TIM to about 340 it idels fine at cold start but once it warms up it will be too rich at about 11 to one .I am currently running 303 TIM and around 462 k constant and latency at 710.
Thanks .

[Matt]

At cold start it is really lean maybe 16 to 1 even goes into 17 to 1 i need some input on correcting this issue as it makes it hard to drive and will even stall out at cold starts.

Found when I had my RB30 when running Z32 MAF I had to increase the 'temperature enrich' tables a fair bit until it ran right and gradaully lowered until the 80 degC column. This was before FP was available

It seems enrichment is affected to do with moving from 2-7V MAF to a 0-5V MAF and then the associated movement of K constant (which affects TP).

In this case your K is lower (462) compared to factory (607). You could try increasing K constant (may have the increase your TP scalers) and lower TIM and see if that helps

[cmbz31]

OK so temperature enrich tabels will have no effect on the cold start lean out issue.? So does the feature pack version atomaticly adjusts for cold start operations.?

Thanks

[Matt]

Nothing is automatic...

Cold start tables are 'after start enrich' used for about 3-5 seconds after crank. Then after this only 'temp enrich' table is used for enrichment on the highlighted temperature column

[cmbz31]

OK the only thing is i dont see a temperature enrich option in the nistune?

[Matt]

This one here? Its called 'Enrich (cold crank)'

It now does both warm/cold as the tables were combined into a single table for feature pack

[cmbz31]

OK sounds good Matt i really apprieciate your help. So would you say to increase the K constant up back to stock and turn down the TIM.? Or would i be increasing the K constant up higher than stock for the bigger injectors. Im only running 440cc so maybe stock K then increasing the scales a bit no?

[Matt]

Firstly, try putting K constant back to stock and adjust TIM only (so you have 14.7:1 at cruise when warm). You may have to adjust the fuel and timing scales. Let me know how that goes

[cmbz31]

OK sounds good. Thanks .I did scale up the fuel map a bit so I would have to match the timing scale with the new fuel map scale correct.? I put the k constant back to stock and what would you know it doesn't lean out no more on cold start wow I'm amazed.. I'm thinking now I can have fun driving it and fine tuning it from here on out...

[cmbz31]

Also not sure why my fts is going up all of a sudden it hits about 28% and floods the engine then goes back to 0% all of a sudden it wasn't doing this before when I had the k constant at about 470 not sure why I'm thinkingmaybe it goes out of scale and wants to lean out.??

[Matt]

Thanks .I did scale up the fuel map a bit so I would have to match the timing scale with the new fuel map scale correct

Yes that is correct

I put the k constant back to stock and what would you know it doesn't lean out no more on cold start wow I'm amazed.

So at cruise you have 14.7:1 with near 0% trims?

Also not sure why my fts is going up all of a sudden it hits about 28% and floods the engine then goes back to 0% all of a sudden it

Does it climb quickly (staircase?). Can you post a log and current tune file?

Are all other feedback flags and O2 parameters set to standard? I've seen disabling o2 sensor flags can do this? Is TIM adjusted to 14.7:1 at cruise?