Light throttle lean issue when using FP ecu's need help please

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scottmt21
Posts: 2
Joined: Sat Jun 30, 2012 4:01 am

Light throttle lean issue when using FP ecu's need help please

Postby scottmt21 » Wed May 16, 2018 2:44 am

z32 TT dual maf's with Selin Translator set to AVG. Nismo 740cc. type 2 board(s) with FP
Car runs fine with non feature pack ecu in it.
Change over to FP ecu, load a FP tune and set the settings for K, TIM and Lat.
K set to 575
latency 800
tim 340
These settings are recommended for this car and setup by concept z performance in arizona
After only making these basic changes to make the car run, it idles and revs well. afr's are good.
The issue is that if you lightly press the accelerator pedal and raise rpms to between 1500 and about 2800, the car goes full lean. It will then start sounding like it is on a two step. Brap brap brap until i let of the gas or push it further to overcome.
While this is happening, the hard idle switch is off, injector duty shows it is increasing, Maf voltage increases etc. But the car feels like it is stuck in the idle maps. I have increased the fuel maps in the affected cells and nothing. I can max the map through the roof and it stays lean. BUt if i floor it from idle, the maps will make the wideband very rich through those cells. It is like the ECU is not reading the maps.
I have 2 different FP ecu's that do the same thing. No matter what z we put them in. There is also another guy I met that had a FP ecu tuned by an authorized Nistune shop and his car does the same thing. Not as bad but it is there. This effects the car real bad when driving slow through parking lots and when trying to take off from a stop light. Lots of bucking. But when you get past it, afr's are great, power is good all is fine.
I am thinking there is some sort of correlation between the K and the TIM. It seems to slightly help if I raise K and lower tim to offset. But then the car won't rin very well as you have to take it pretty far to make it change.
I have also tried to adjust the maf translation and this will help, but seems odd that only in those rpm areas I need to raist the voltage quantifier from the 500-600 area to over 1000 to make it better but the rest is fine as is?
Again, if I put a non FP ecu into these cars, all is fine so I am ruling out a mechanical issue here. I am at my wits end with this as it seems nothing changes it.
Has anyone else dealt with this and have an answer?

unex
Posts: 78
Joined: Sat Aug 06, 2011 6:59 am

Re: Light throttle lean issue when using FP ecu's need help please

Postby unex » Wed May 16, 2018 7:24 am

for me sounds sort of idle switch issue (even if it says its off). I would try to adjust TPS for higher voltage while its on idle and see if there is any correlation

Matt
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Re: Light throttle lean issue when using FP ecu's need help please

Postby Matt » Wed May 16, 2018 11:11 am

z32 TT dual maf's with Selin Translator set to AVG. Nismo 740cc. type 2 board(s) with FP
Car runs fine with non feature pack ecu in it.


If you use the exact tune from the non-FP ECU and load into the FP ECU (so that TIM=512 still, default). It should run the same. Have you tried this?

The issue is that if you lightly press the accelerator pedal and raise rpms to between 1500 and about 2800, the car goes full lean. It will then start sounding like it is on a two step. Brap brap brap until i let of the gas or push it further to overcome.


Do you have knock fault code? Does the ECU 'beep' at all in tuner mode? There was a firmware update from Aug 2017 (in latest FP ROM pack) to address a Z32 FP issue when the ECU switched to knock maps it would not read correctly.

When was the board purchased or FP firmware updated?

While this is happening, the hard idle switch is off, injector duty shows it is increasing, Maf voltage increases etc. But the car feels like it is stuck in the idle maps. I have increased the fuel maps in the affected cells and nothing. I can max the map through the roof and it stays lean. BUt if i floor it from idle, the maps will make the wideband very rich through those cells. It is like the ECU is not reading the maps.

Sounds like it might be trying to access the knock fuel maps here, but instead reads a set fixed value (because of the firmware issue)

Make sure you have the latest firmware in the board, and let me know if still an issue. For USDM MT Z32:
Z32_VG30DETT_31P0F_1990_MT_FED_FP.ent (date stamp 10 Aug 2017)

Matt
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Re: Light throttle lean issue when using FP ecu's need help please

Postby Matt » Wed May 16, 2018 11:13 am

This was the original problem report:
http://www.nistune.com/mantis/view.php?id=94


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