Could someone please explain to me how to use the AEM Injector Wizard to size injectors? I want to learn how to do this and not just have someone do it for me. I understand the fuel and timimng tables I just cant figure the voltage latency for my injectors. I am using Denso 720 2ohm injectors.

 

As I know there are three 4 main types of injector with different latency.

NipponDenso with needle. (japanese evo8) have 560 and 720)
NipponDenso ball and seat (has plate with little holes) (~540 - Used in european evo 8)
(that is why in european and JDM cars are different voltage compensation )
Delphi
Siemens (both ball and seat of our sizes )
PTE,RC and others uses delphi or siemens injectors-they just calibrate them to match the flow and put their label on them - so the have to be the same in latecy and voltage within one size and make.

 

To be precose they are the Greddy/Denso 720's. From looking at them thay have a little needle looking thing in the end of them.

 

JDM evos has the plate and holes type .. 2 holes in fact ..

so sometimes I find us going backwards when you upgrade to denso 700cc wih single port (bigger but the spray pattern may be compromised) ... my thoughts

 

You should post this question in the AEM forums, this is EcuFlash.

 

I am ussing Ecuflash. A lot of people are using the AEM software to figure out how to size their injectors and the voltage latency.

 

Got another question for the experts...

I'm starting to hone in on the right injector scaling size for my 780cc injectors ... looks like it's gonna be 597. Here's the thing, though:

If I let my car sit and idle the fuel trims start to climb.

I have my idle set relatively high at a target of ~1050 rpm, which has me idling at close to 14V (usually around 13.8V). If I bump my idle voltage latency up at 14V, will it affect fuel trims during cruise?

l8r)

 

It shouldn't affect it much, the higher the duty cycle, the less the latency value matters.. but it will need a little refining.. I'm somewhat in the same boat..

My general observation is to get your trims close, then make adjustments for the higher RPM, then when they drift again at idle, use the ECU's fuel map to get the idle trims back along where you want them..

If you find the car trims lean, when you come to a stop, the car should swing rich for a short while.. if it trims rich while driving, then it will swing lean when you stop.. You need to see what the trims look like when taking a longer drive.. that should give you some insight..

 

On average, your crusing injector pulsewidths will be double your idle injector pulsewidths. So, any changes that you make in the injector deadtime will affect idle twice as much as it will affect cruising. But, yes, it will affect both if they are both in the same V range that you are adjusting for.

DSMLink used a global fuel setting slider and then an injector deadtime value to tune the injectors. Their global slider was basically the injector scaling value in the ECU and their deadtime was basically what we get to adjust in the voltage latency tables.

But, with the years of experience with DSMLink and seeing others dial in injectors, the above holds true.

Basically, what we did with DSMLink is as follows:

1. Choose a global setting (ECUFlash injector scaling number)
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to increase your global fueling, or in terms of ECUFlash, you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to descrease your global fueling, or in terms of ECUFlash, you need to raise your injector scaling number.
5. If idle trim is more positive than cruise trim, then you need to increase the dead time, or in terms of ECUFlash, you need to increase the latency value.
6. If the idle trim is less positive than the cruise trim, you need to decrease the deadtime, or in terms of ECUFlash, you need to decrease the latency value.

Note: After #5 or #6, you may need to readjust #1 accordingly.

Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.

Eric

 

Good post! You definitely articulated that better than I could..

 

I'm using the FIC 750 which is a similar style injector, and I'm actually using the 750 scaling with this and a latency of 1.006@11v and .789@14v. I started low where you are and just kept moving up the scaling and making adjustments to the latence until I got my idle within 2% and cruise is not far behind. I've also found that my WOT tables Have not had to be altered at all. With the smaller scalings the car would go pig rich at WOT but no AFR's are in the high 10's low 11's. I'm going to the dyno Sat. and I will optimize them there (DD dyno) , but I don't anticipate having to mess with them much.

 

Thanks guys. That helps me a lot.

l8r)

 

l2r99gst
You rule I was starting to understand how the katency and all that crap worked, thanks to Malibu, and you just completed my training. Now I understand fully how to size my injectors, or at least I think I do.

 

Back from the dead... This seems like a gem of a thread.

I had two questions:

1.) Are the FIC injectors in the table below the same as those provided in
this link here ? ----> http://www.fuelinjectorclinic.com/cart/mitsubishi.htm

2.) How has the method in this thread worked out for those who
attempted to scale thier injectors ?

 

i have the FIC 650 injectors. i used the latencys listed below and scaled the injectors up to 550. however i kept getting CEL for the P0171 code. it would be way to lean at idle, but the trims could compensate enough to have 14.7 afr. its just that the trims would be nearly maxed out. at WOT, it was just about dead on with some minor tweeking to do. because i need to pass emmisions right now, i scaled the injectors back down to 520 so it wouldn't throw the code. so far no CEL lights. car starts every time on the first rotation even with the mini battery. car idles just fine with either scaling value. i think once i get past the emmisions testing i'm going to leave the scaling at 520 and tune the WOT accordingly. that way no more CELs.