Inconsistent fuelling, Z32 MAF issue?

[Vetal]

Guys does anyone have problems with inconsistent fuelling changing with weather? One day it can be spot-on and the next day it is off by 10% (in most severe cases). Mostly problem is with idle and cruising, so with low-load.
I suspect that Z32 MAF could be a problem giving slightly different output thus altering fuelling a lot on small 1.8L engine on low-load. Does anyone else have such problems with his daily driver?

[CoZZm0]

If you don't need the amount of airflow that the Z32 can read, i'd go for the same size, but a more suited rating such as the R32/33 MAF. Might help the issue.

[Vetal]

I think I have around 400HP now so I need the flow...
But I have to know, whether it's MAF's problem, or just something wrong with my setup which can be fixed

[CoZZm0]

Is it a genuine one is the first thing i'd ask, because the copy ones can cause problems (not sure if this problem specifically). There's a great there on here somewhere that shows the common differences between genuine and copy.

If it is a genuine one, then hopefully someone can help you out.

[Vetal]

I had no reason to doubt it's genuine so let's assume it is...
I just wonder if anyone else has problems with weather influencing the tune

[raddy]

I dont use narrow band lambda anymore and have low load area mapped to very lean mixture, so any changes will be easily noticeable, but I never noticed any change even in 36deg weather, nor for 10deg like now....
Im using RB20DET AFM.

If your fuel pressure is stable, than I would say that AFM is probably dodgy. Try to made logs and compare AFM voltage when fueling change occur...

[Vetal]

Yesterday I had 1.20V at idle, today I had 1.10V. In Z32 MAF table first 2 cells (it jumps between them) are 1.04V and 1.12V, and values between them differ by some 25% (1.12V - 505, 1.04 - 405). So even tiniest cell change causes major calculated load change.
Do your MAF tables look alike?

[Vetal]

hmmm, what's very interesting... I've just opened my bin in 0.9 Nistune version and AFM translation table started with 0, not 1024, with those same "405" in the first cell. After I installed 0.10, first cell started at 1024mV just like in the car... I wonder which cell would ECU in reality use in 0.9 version...

[louiswun]

hmmm, what's very interesting... I've just opened my bin in 0.9 Nistune version and AFM translation table started with 0, not 1024, with those same "405" in the first cell. After I installed 0.10, first cell started at 1024mV just like in the car... I wonder which cell would ECU in reality use in 0.9 version...

CA18DET ?

[Matt]

This was fixed from about 0.10.16

S13 CA18DET VQ map display. Actually 1040mv first cell, then increments

[Vetal]

So did anyone have issues with Z32 MAF on idle showing sometimes 1.1V and other times upto 1.3V on Nistune?
Is it really weather effect, or faulty MAF maybe?

[bachig24u]

is the idle rpm higher to coincide with the MAF voltage being slightly higher?

[UNISA JECS]

Does your Z32 MAF have both screens intact?

How did you ground pin "C"? (This one should be connected to the shielded wire)

How did you ground pin "D"? (This one should be connected to an engine ground lug)

[Vetal]

bachig24u, no, idle rpm is around 850 when everything is warmed up. Although these days when MAF reads low and engine idles at 18:1 AFR, idle obviously is harder to keep

UNISA JECS, both screens intact. Can't answer about different ground pins at the moment...

[BlueRB240]

Vetal check out this thread on Zilvia http://zilvia.net/f/tech-talk/501118-ne ... ption.html