Injector scaling and latecy for different injectors.
Evolving Member
Joined: Jun 2004
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Thanks dude, will go try it out and feeback to u..so i use what injector scaling for this HKS 680 (aka denso 660)? Please advice.
My fren has the Power Enterprise 700cc, do u happen to know what are they similar to what brand injector latency? Appreciate if you can advise...
cheers!
My fren has the Power Enterprise 700cc, do u happen to know what are they similar to what brand injector latency? Appreciate if you can advise...
cheers!
Thanks Eric, that was awesome. It will certainly make tuning injectors easier for me.
For the record, this is how it needs to be written in the Evoscan data file. I also switched the request ID from LTFT low and LTFT high to make them correct.
Display="Fuel Trim Low" LogReference="FuelTrim_Low" RequestID="0C" Eval="(0.1961x)-25" Unit="%"
Display="Fuel Trim Mid" LogReference="FuelTrim_Mid" RequestID="0D" Eval="(0.1961x)-25" Unit="%"
Display="Fuel Trim High" LogReference="FuelTrim_High" RequestID="0E" Eval="(0.1961x)-25" Unit="%"
Display="Oxygen Feedback Trim" LogReference="O2FeedbackTrim" RequestID="0F" Eval="(0.1961x)-25" Unit="%"
For the record, this is how it needs to be written in the Evoscan data file. I also switched the request ID from LTFT low and LTFT high to make them correct.
Display="Fuel Trim Low" LogReference="FuelTrim_Low" RequestID="0C" Eval="(0.1961x)-25" Unit="%"
Display="Fuel Trim Mid" LogReference="FuelTrim_Mid" RequestID="0D" Eval="(0.1961x)-25" Unit="%"
Display="Fuel Trim High" LogReference="FuelTrim_High" RequestID="0E" Eval="(0.1961x)-25" Unit="%"
Display="Oxygen Feedback Trim" LogReference="O2FeedbackTrim" RequestID="0F" Eval="(0.1961x)-25" Unit="%"
I know... but I was quoting the post on the start of page 14 in response to the post at the bottom of 13. I was just hoping someone had it available. Guess I should have searched - but quoting is so much easier 
ok! I gave up trying. Can someone post me a good scaling numbers specific for Precision 880 injectors. The one from the AEM chart didn't work for me. I tried some settings but no good so far. It maybe something else but I want to try some good proven 880 settings first. Thank in advance.
(128-x)/128 would leave us with values of 1 to -1. Perhaps (x-128)/128, then multiplied by 25 would work as well. (x-128)/128 would give us -1 to 1. Multiuply by 25 and we would arrive at the same equation as above:
25[(x-128)/128)
(25x-3200)/3200
.00781x -1
So, it turns out to be the same. I didn't create the original equation, but it looks like this is how they came to the proper equation.
Eric
Well, that would give us a range from 10 to -10. First, that is backwards and we know that the range for the fuel trims are greater than 10% at it's maximum correction.
I don't know who came up with the exact equation, but it seems to fit perfectly in my experiences with helping people with trims, etc.
Eric
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From: Tri-Cities, WA // Portland, OR
The fuel trim range in ECU units is 0 to 255 with 128 being the zero point. (I think that this was already mentioned previously.) To represent this range in percent, the formula would be:
scaling = 100*(x - 128)/128 = 0.78125*x - 100 (%)
ODB-II scanners use the following scaling:
ODB-II LTFT scaling = (0.78125*x - 100)/4 = 0.1953*x - 25 (%)
Based on this, it seems that the 0-255 range is scaled somewhere in the ECU to represent a LTFT range of -25% to +25%.
MalibuJack is using the ODB-II scaling in Mitsulogger because its most likely the correct scaling.
I looked in the ROM code this morning to try to find the scaling, but there wasn't anything obvious. I found all the references to the LTFTs, but none of them pointed to any scaling or even the code that calculates the current trim level. All I could find is that the ECU apparently doesn't like it when the LTFTs are outside of the -12.5% to +12.5% range (ODB-II scaling).
scaling = 100*(x - 128)/128 = 0.78125*x - 100 (%)
ODB-II scanners use the following scaling:
ODB-II LTFT scaling = (0.78125*x - 100)/4 = 0.1953*x - 25 (%)
Based on this, it seems that the 0-255 range is scaled somewhere in the ECU to represent a LTFT range of -25% to +25%.
MalibuJack is using the ODB-II scaling in Mitsulogger because its most likely the correct scaling.
I looked in the ROM code this morning to try to find the scaling, but there wasn't anything obvious. I found all the references to the LTFTs, but none of them pointed to any scaling or even the code that calculates the current trim level. All I could find is that the ECU apparently doesn't like it when the LTFTs are outside of the -12.5% to +12.5% range (ODB-II scaling).
Last edited by mrfred; Sep 25, 2007 at 03:22 PM.
I found a few people that mentioned the FIC 750's in this thread but wasnt confident enough in the info to piece together any scaling or latency values. Can someone please help me out with this?
I currently have warm start issues (starts perfect when cold, then cranks over multiple times when trying to start warm) which I'm sure are related to the scaling and latency.
Thanks in advance.
I currently have warm start issues (starts perfect when cold, then cranks over multiple times when trying to start warm) which I'm sure are related to the scaling and latency.
Thanks in advance.
I noticed that the AEM excel file posted in this thread does not have the latency numbers for 4.69 volts slot in the ECU inejctor battery voltage latency table.
Does that mean that this number is not necessary to modify? What do you guys use instead?
Are there any updated AEM wizard numbers?
Does that mean that this number is not necessary to modify? What do you guys use instead?
Are there any updated AEM wizard numbers?
From what i have seen dialing in a few injectors (RC, FIC, & Denso) I have noticed that this number is not used and doesn't need to be changed...but different people do different things...although when i have changed it on my own car, it has not changed the fuel trims...if the car dips to 4 volts we got some issues....