Thread: resetting the fuel logs

Yeah, but who doesn't argue with DH? He is kind of fun to poke at.

Originally Posted by 91parkave

Before u call me out use your brain to understand the chronological format of responses on a forum. My reply was to gtppowers comment.

well in that case...your statement is 100% incorrect in regards to how long it will take for the fuel trims to learn. that or you cant understand GTPpowers metaphor

Originally Posted by 91parkave

Godforbid someone correct someone else, and i argue with dh. I usually agree with you

correcting people and arguing is half the fun of the internet.

Originally Posted by SgtMarshal

I have another question: I have 42.5 lb injectors and after reading through Jerry's tuning guide decided to do the math to figure out if the scaling had been done correctly. I checked the stock IFR and then multiplied by .847, and I found my injectors had not been scaled correctly, then I drove around for a couple hours to relearn the trims. when scaling the injectors is this the only variable I need to account for, meaning multiplying by .847? To continue, do I also need to resmooth my maf curve after adjusting the trims? My other question is: when coasting down a hill is a lean condition common? for example, values of 15 or 16 happen a lot in my ltft's. this may seem like a common sense question, and I understand why it leans out, but I also understand that lean conditions are not good.

Are you tuning with HPT or DHP?

To answer your downhill question, when you let off the gas, you enter deceleration enleanment, which will lean it out. Helps to save fuel.

Originally Posted by SgtMarshal

I have another question: I have 42.5 lb injectors and after reading through Jerry's tuning guide decided to do the math to figure out if the scaling had been done correctly. I checked the stock IFR and then multiplied by .847, and I found my injectors had not been scaled correctly, then I drove around for a couple hours to relearn the trims. when scaling the injectors is this the only variable I need to account for, meaning multiplying by .847? To continue, do I also need to resmooth my maf curve after adjusting the trims? My other question is: when coasting down a hill is a lean condition common? for example, values of 15 or 16 happen a lot in my ltft's. this may seem like a common sense question, and I understand why it leans out, but I also understand that lean conditions are not good.

42.5lb injectors:
that is correct, when i first looked at your tune i noticed they were scaled for 43.7 or something. honestly its close enough. if you change it you can count on your trims going a bit goofy again as you change the baseline for what the car uses to calculate fuel. where did you get the .847? DHP is kinda goofy because it measures injector size in msec/gram of fuel i believe. everywhere else uses like lb/hr or cc/min. so there is some math involved in converting.
MAF table:
if you are using that original MAF worksheet that you sent me it automatically smooths the curve for you after you put in your data from a scan and your BIN.
Lean:
it goes lean because of the deceleration enleanment in the computer. its perfectly normal and does not need to be adjusted.

Neb has this covered. I need to go do some work so I can build a car faster than his.

He got the .847 by finding the percent diffrence between stock ifr and new injector ifr. Im assuming

that would make sense except gtp injectors are 33#/hr and he is running 42.5#/hr injectors so .847 is not right.

Originally Posted by SgtMarshal

In Jerry's tuning guide, which was made to help people using DHP, he says to multiply by .847 when switching to 42.5 lb injectors. I didn't realize there was a deceleration mode, but that explains the leaning out. I found a new tuning application, it is called "Table Modifier, the Scan Data Thingy." it has a few tools that I want to start using, VE tuning being one of the tools, but also it has a timing table adjustment tool. The application has a button to click that will add 1 degree of timing to all cells that do not have KR and it cuts timing by 50% in cells that do have KR. The question that arose in previous discussions is that it may not be a good idea to add 1 degree universally because the idle could be affected and so at what rpm is it good to start adding timing? Is it safe to add timing before the VE table has been fully adjusted?

I can send you a link to my dropbox if you want to look at the guide and/or the application.

I will probably have to check my maf smoothing after adjusting the injectors.

if you have the MAF dialed in to 0 to -5 everywhere you can start the ve tuning. if you dont, dont bother wasting your time. the maf will likely need to be adjusted after changing the IFR. i generally dont mess with the timing below 4000 rpm unless im trying to adjust cruise timing for better MPG. i dont like that tool for adjusting timing as i think you are better off just using common sense. basically dont run more then 22* at WOT, your dynamic cylinder pressures will get to high. at that point you are better off running a smaller pulley and dropping the timing back to about 18* and working it up slowly as long as it doesnt knock. eddie's ve tuning tools (the table modifier thingy) are great.

In my opinion you need to find your injector data. And what they recommend for your fuel pressure so you ccan start with that in your ifr table. get your maf tune done but dont smooth it everytime you reflash.if it were me id go back to stock maf curve and start over.