FWIW this is also the reason why we run bigger injectors, so your not blowing fuel into the back of the valves where it could pool.. Bigger injectors, shorter duty cycle, more chance fuel all atomized fuel is ingested during an intake cycle..

 

I am not convinced that the calculated IDC % is accurate. The equation itself is correct, but some of the data we are getting must not be. My reason is that prior to upgrading my injectors I was seeing IDC as high as 115% but still retained the ability to adjust fueling. I'm guessing the IPW in evoscan / mitsulogger may be off, but that is purely a guess.

-Paul

 

If it was off, then it would be off on the MUT tool too, since the value is calculated from a byte value from 0-254 and the formula is derived from the same data.

 

Sorry to bring this back from the dead, but it seems to be the thread most relevant to my problem, of which i believe you all will find somewhat interesting.

I had the same problem at the thread OP w/ my mods (in sig.) maxing out the stock injectors (according to EvoScan, at the time).

SO, myself, David B., and a few others decided an injector upgrade to 680cc injectors would be the most efficient approach to solving my problem; as we never could come to a conclusion as to why i was running such high IDC's with basic bolt-ons in the first place.

Now many variables come into play here, and i will try to cover them all; but if i miss some, feel free to ask accordingly: With the new Precision 680cc injectors, my brand new walbro with brand new filter, and NOW MJ's MitsuLogger (same modifications as before, and on the same tune) I am STILL seeing IDC's well above 100% from 3rd-5th gear anywhere above 5k RPM's at WOT...

I do believe the Walbro was installed correctly, as well as the injectors; because i personally did the install on both modifications. All 4 injectors, as well as the Walbro FP were installed exactly the same as the stock counterparts were sitting from the fatory.

So in conclusion I think I have eliminated some of the possible factors contributing to this problem (as adding larger injectors got us nowhere), and have hopefully got us one step closer to finding out what is causing this.

 

Are you monitoring afr with a wideband O2 system?

 

No.

I understand my situation leaves much to be desired, but it was worth stating.

 

Did you rescale your rom for the larger injectors?

 

Thats also my question.. Was the ROM rescaled using ECUFlash? Or you only changed the value that Mitsulogger uses to CALCULATE the load on the engine..

changing your scale and voltage latency the in your rom with ECUFlash is the ONLY way you can rescale your injectors. Mitsulogger is only a logging tool.

 

MJ, since its relevant I do have a question on injector scaling. I have the excel sheet that was posted that shows the latency values, but do you need to change the injector size scaling as well? I saw a calculation somewhere, something like 680cc's minus 10% would be 612, and thats what you put in there. My question is this: is it one or the other, or are both necessary?

 

No, i didn't rescale the ROM for the new injectors. Though in the next couple days it will be, when Jestr gets back to me.

So i take it, the inj. pulse width is going to lower once the ECU is calibrated for it? I figured the ECU is telling what the inj. pulse width is, regardless of which injectors...

Either way, i will get some new logs when i get my new map back from Jestr; I'll let ya'll know how it goes.

 

So you put in larger injectors, didn't rescale them in the rom, and you don't have a wideband, but wonder why your IDC's are so high?

:-/

 

I don't care if my car is running as rich as possible, it shouldn't be maxing out 680cc injectors at 300 whp, regardless.

I acknowledged that scaling needed to happen, and it is being worked on as we speak; i just didn't know it made that huge of an impact, which now i odviously do.

Like i said, i will get back to this as soon as i get that map back/loaded and get some accurate datalogs.

 

If they are not scaled properly, and the fuel maps are not tuned for them, that richness will cause high IDC's.

Get them scaled correctly and tuned correctly and the world will be good again.

 

Razor, I know you tune for injectors. Any ideas on my post above? Do you change just the Injector Battery Latency Compensation, or does the Injector Size Scaling need to be changed as well? Whats the formula? I have a friend doing injectors tonight, and was hoping to give him a quick fix till we can sit down and full tune it.

 

both need to be changed