FUEL TRIMS /Pocketlogger

[DJ Galant]

I am just curius why is that happen - whatever i do when i am playing with my safc at idle - the STFT and LTFT stay the same...
i mean STFT may change 1 to 2 % at the time i adjust it, but i don't see any signbificant changes...
Now, i try to reachin things up, my car is about to die due to additional fuel, but the STFT don't change almost (maybe like 1 or 2 percent)...
Same things happen to my LTFT...
NOw, if iam trying to lean it, my STFT and LTFT don't change either...(the car is about to die to and i can hear little puppings =lean).


Wonder why..
Anyone experience that?

[ken inn]

on my logger, i have low, med, and hi fuel trims, and also o2 trim. if all you have is short term and long term, long term will change slowly. here is how i set my LO fuel on my afc. on the logger, select o2 trim, o2 volts, rpm, low, med, and hi fuel trim. then, with the motor FULLY WARMED UP, set the afc at 1k, hold your rpm to 1k, and look at your o2 trim. it should be bouncing all around, but what it is trying to do is keep it at 100. low fuel trim also wants to be at 100. if low fuel trim is below 100, you are rich, and your o2 trim will be bouncing around above 100. adjust your afc until your o2 trim averages 100, you should see your low fuel trim slowly changing. it will also become 100. adjust each level of the afc, 2k, 3k, 4k. on my car, above 4k, the ecu goes open loop, and uses set fuel maps, so it pretty much has no effect on the LO throttle settings. on the HI trottle settings, you will need to go out and do some wot pulls and datalog them.

[DJ Galant]

u got OBD1 system KENN....
I bet u, cuz we don't have have mid trims...besides the fule trims on the sofware i use arein the % ad they arelow numbers such as 12 or20....
Thanks though...

[ken inn]

ok, do you have o2 trim? you can tune by that, too. st(short term) fuel trim takes in a lot of input to make changes, but the changes are very quick. lt(long term) will take much longer to change. if i remember correctly, you are running like 550 injectors, right? imho, those are WAY too big. if you run injectors way too big, then on the low end, the pulse width is erratic, and you dont get good idle because it simply cant spray that good at such a low setting. also, fuel pressure has a lot to do with it, and, brand of injectors. some injectors, like lucas, dont like to idle. for example, my vr4 came stock with 450cc, 10.5 lbs boost stock. however, this car easily supports 14-15 lbs boost with the stock fuel system, no other changes. that would equal to about 250 crank hp. now, i have 560's @ 17 lb boost, and lots of mods to increase flow(2g mas, big 16g turbo, dejon intake, fmic, exh) and i am still running a tad rich at wot. at 1k rpm, i have the afc at -20 in order to get my fuel trims in line.

[DJ Galant]

what is so good about 2g maf sensor?
do u think i should swutch to that? is it possible to do?

[ken inn]

what is so good about 2g maf sensor?
do u think i should swutch to that? is it possible to do?

in the talon/eclipse/laser factory equipped turbocharger world, there is only 1g and 2g cars. 1g is 90-94, 2g is 95-99. these are all turbo cars, the galant vr4 is also included, which is a 1g, slightly different from this group. the 2000 eclipse is considered a 3g, but since it is not a factory turbo, very few, if any, are in the dsm groups. since there was a huge difference in the 95 and later cars from the 90-94, hence the 1g/2g. for instance, the mas on the 1g cars is all the same, likewise the 2g. the 2g mas, which is the same as on your car, flows 22% more air than the 1g, and is considered an upgrade for the 1g cars, BUT, you must also include bigger injectors, bigger fuel pump, and fuel control. the 2g mas is shared with other mitsu cars, like the 94 and later galants, monteros, diamantes, pickup trucks, and a lot more. it is oval. the 1g mas is kinda rectangular, and sits INSIDE the air box.

[JiP]

The 2g sensor is the same as the 7g maf sensor why would he have to upgrade fuel system? I dont see the need, but I do not know what his setup is either.

[ken inn]

i was trying to explain the difference between the 1g and 2g talon/eclipse/laser and galant vr4 TURBO cars. this person already HAS the 2g mas on the car. my vr4 had the 1g turbo mas on the car, i replaced it with the 2g mas, which fits turbos, non turbos, trucks, minivans, maybe even golf carts. in the t/e/l turbo world, the 2g mas flows 22% more than the 1g. just bolting on the 2g mas on a 1g car will make it run super lean. to compensate, the stock injector is a 450cc, a 550cc will run with very little fuel control, but now you need a bigger fuel pump. and, to really make it work, some kind of fuel control(i have an afc) is necessary. with the bigger pump, you should also have and adjustable fpr. but with all of this, you can now REALLY up the boost.

[JiP]

See thats where I get confused, the 7g galants have the 2g mas and only have 250cc injectors I still dont see why you would upgrade injectors. Im running a 60mm tb and getting about 10% more airflow over stock and I am no wheres near close to needing to upgrade my fuel system for that.

[DJ Galant]

kenn - thanks for the info on maf...though i know excately what 1g 2g and 3 g is..I go on dsm forum frequently...(many of them)..so i know what's up. I just didn't know that i have alteady the same maf sensor as turbo 2g eclipse/talon.Interesting.

[JiP]

7g galant? If so we have the same engine as a eclipse Spyder and we can use almost all the parts from a 4g63 engine found in the turbo cars. We can also use a lot of suspension upgrade parts and shifters etc made for Eclipse. in case you didnt know already https://www.thegalantcenter.org/style_emoticons/default/smile.gif