Nistune Forums

Matt have a question, it looks like this has a scale from 0 - 255 value

Do you know what each values relationship is in regards to voltage.

For example:

184 value = ???? voltage

and so on...

viewtopic.php?t=707

its not a simple calculation we can easily translate

The reason I ask, because I have been tunning my own car for a lil while now and I have this feeling that there is somehting missing in regaurds to latency. For example there seems to be a trade off of some sort. I have experienced with my setup:

KA24DET
T25
370cc etc etc
redline 6900rpm


Say I use and injection latency of lets just say ~720ms, I can tune my AFR's for idle cruise and boost up to ~4700rpm with no problem at all........after 4700rpm and above wideband reads dead lean (I believe this is because im actually to rich not lean).........

Now if I bump up the latency say to 950ms, ofcourse idle get richer pretty much everything gets richer and now my AFR's will be controllable up towards readline......

Now here the weird thing if I keep the 720ms and lean out my fuel map in the boost region quite a bit im also able to hold onto my AFR closer to redline.

I know that latency is always tacked onto to target pulsewidht, exmaple:

2.00IPW + .720ms = 2.720 IPW

What I described seems totally contradicting, and what stumps me further is how increasing latency in one senario allowed me to hang onto my AFR's longer and in teh other senario leaving latency alone and decreasing my fuel map values leaner also did the same. Sorry I know this is all weird and a little hard to describe, I also know that k constant plays a roll to in this.

Ok Matt think I narrowed down my problem, it appears that my wideband sensor was become fouled. I cleaned it with a torch and seem to be getting alot better consistant readings, will update more later after I drive teh car more.

no probs. keep us posted

Matt wrote:no probs. keep us posted

Just to update this the problem was due to a bad wideband o2 sensor and was the reason I was getting full lean readings when I was going into boost, but the wideband was no good at reading AFR's richer than 13.1 pretty much for it read full lean.

I performed this test on my Innovate LM2 wideband

http://www.youtube.com/watch?v=1mb4VmDd0ao

Try re calibrating the Innovate unit with free air to see if the readings go back to normal

Matt wrote:Try re calibrating the Innovate unit with free air to see if the readings go back to normal

Back in 2008 is when this sensor went bad and its also when my S13 KA24DET got totaled, believe it or not I still have the bad sensor from 2008 and I also bought a brand new sensor in 2008 just a few days before my S13 KA24DET got totaled but never got aorund to installing it before the car got totaled but now im turboing my P11 SR20DE(T) and for shits and giggles I installed the known bad sensor which required a calibration and it work as long as the car is at idle and cruise condition just as it did in the S13 KA24DET but once you got on it the sensor always went to dead lean so I know its a bad sensor and just to confirm I installed my new sensor and it works likes its suppost to.