How is injector duration (ms) calculated?

streetbike · Post by **streetbike** » Sat Mar 22, 2008 9:41 pm

OK !!

very good so !!

So I can expand my map for more boost now....

I was affraid that my 550cc was maxed out too early....

thank you for all Matt !!

streetbike · Post by **streetbike** » Fri Apr 04, 2008 2:22 am

Another thing I do not understand.... on my logs the pulsewidth drops from 9ms to 5ms at about 3200-3300 when throtle wide open.

Is it real or not ?? I do not feel it in driving..

the thing I found strange is that before the drop the value is same as value in map, and after that the value is 1/2 of the value on the map....

Matt · Post by **Matt** » Fri Apr 04, 2008 1:13 pm

can you post your log file and I'll check the exact pulsewidth on the scope again based from your inputs

streetbike · Post by **streetbike** » Sat Apr 05, 2008 2:36 am

Here is one, each time TPS is at WOT you will see this strange thing ..

first one at around 5 min

Matt · Post by **Matt** » Sun Apr 06, 2008 12:13 am

I've had a look through it, and strange since TP doesnt drop but the injection parameter does by a fixed amount

I tried playing around on the bench but my TPS doesnt go as high as yours so couldnt make the same scenario. However the injection parameter does definately do what is displayed (see picture)

In regards to where you logged that point, unfortunately I cant repeat to confirm, but is noted your revs and speed do not drop at all

Perhaps there is another variable which has final injection and this is a preliminary calculated variable used for determining it

streetbike · Post by **streetbike** » Sun Apr 06, 2008 2:15 am

I have made several test last night at diffÃ©rent RPM.

it appens only when in full throttle and only after 3000rpm

but if I sart at about 3500rpm it happens 100-200rpm later

it seem to be related to turbo lag ( I have a GT2871R turbo)

as the fuel pressure is related with boost maybe it is the correction for the raise of boost ?? as the boost raise, the fuel pressure raise, so pulsewidth drops.. maybe I am false with that..

here is the log with my several tests, you can see it at 42", 59", 1'05", 1'10", 1'14", 1'19", 1'58",and 2'16"

streetbike · Post by **streetbike** » Sun Sep 06, 2009 9:16 pm

bump for this post, I have made some evolutions on my engine and my injectors are maxed out. but nistune says only 53% of duty.

seems that the injection time is wrong on the consult. the way it drops is not good , maybe it passes from full group injection before 3500rpm and after it passes to multi point ??

chris2712au · Post by **chris2712au** » Mon Sep 07, 2009 6:01 pm

looking at the info you would tend to think that it is one of the trims that is doing this..

something like temp correction, knock map, etc...

However if you afr's are not lean as I would expect them to be due to such a significant drop in injection pulse width you would tend to think it was multi point ( double firing the injectors) only way to tell is to put a 12v light in parallel with one of the injectors and stick it in the cab with you.. you will definitely see if it switches to multi point...