Having trouble tuning Hi Throttle on AFC!

[adam355]

Im starting to get Lo Thro kinda figured out so now I can make the car idle decent and be able to low throttle cruise. I'm having a bi*** of a time getting the high throttle though. I don't wanna go do highway pull yet because if I hit the hi th map at all on the street it will just run horrible. When the car stutters when you give it gas...does that mean lean or rich? my lo thr settings are like -1 -4 -7 -10 exc and I'v tried reccomended settings for hi thr, but its not working.

Im running b 16g, 650cc, walbro 255, fmic, afc, logger, everything really you need to support a turbo. Any help would be appreciated.

 

[turbolarry]

Try setting low throttle to -14% across and watch how your fuel trims respond at low throttle crusing. Try -12% across for high throttle, log a run, and adjust from there. That Malory is adjusted right...right?

http://www.dsmtuners.com/forums/showthread.php?t=58403

 

[cfisher]

probably fuel cut. i had the same problem and couldn't even pull a WOT run untill i was at -25 on my highs. keep leaning it out (slowly) untill it doesn't bog and go from there with a log.

 

[adam355]

Yeah, the fpr is set right. Iv been reading that guide too. Man this is a lot harder then I thought it would be. It seems like no matter if i subract or add it runs like crap.

 

[turbolarry]

... i was at -25 on my highs. keep leaning it out (slowly) untill it doesn't bog and go from there with a log.

Yup. Keep going.

( 680's, that's too much for me to handle)

 

[adam355]

I ended up changing my lo throttle richer. Somewhere around +7,+9,+8,+8,+8,+8,+8.

Ill try starting at -25 for hi thr and see what happens.

 

[cfisher]

that seems pretty rich to me. here are my lows.

1K -17
2K -20
3K -25
4K -28
4.5K -30
5K -30
6K -30
7K -30

 

[adam355]

that seems pretty rich to me. here are my lows.

1K -17
2K -20
3K -25
4K -28
4.5K -30
5K -30
6K -30
7K -30

Yeah thats what I thought, but it seems to be running better. I wonder if the honeycombs are still intact in this car...

 

[kpt4321]

Do you have a logger? Don't bother tuning if you don't have a logger or a wideband.

Those settings are really rich, either you're just not tuning well or there is something wrong with your car.

 

[cfisher]

i would def check the honeycombs. you should not be in the positive range at all with 680 cc injectors unless the honeycombs have been removed. if there not there, get some and put them back in.

 

[adam355]

Do you have a logger? Don't bother tuning if you don't have a logger or a wideband.

Those settings are really rich, either you're just not tuning well or there is something wrong with your car.

Yes I have a logger.
Where do you recommend my baseline settings be then with 650 cc injectors? Ill set them there and tell you how it runs. You usually don't take the honeycombs out on a 2g anyways right? I hope theres nothing wrong with my car, it ran fine with the 450s. Also hoping import evolution didnt screw me and give me the wrong injectors.

 

[kpt4321]

Well, what are your fuel trims? Tune the lo throttle map based on the fuel trims.

 

[adam355]

turbolarry may have found an answer for me. I have a walbro 255 and was told my fpr was set right, but with the vac hose off its like 49 psi. I turned it down to 42-43 now, but haven't have had time to do any afc tuning since then. Do you guys think that will make a big enough difference to fix my problem? Kyle, Im working on getting my trims close to zero.

 

[Race94]

How do you set the fuel pressure with the regulator?
Is it VAC off low throttle and VAC on high throttle?
What should the pressure be on a 2g GST?

 

[1fast97gsx]

How do you set the fuel pressure with the regulator?
Is it VAC off low throttle and VAC on high throttle?
What should the pressure be on a 2g GST?

You need an aftermarket fpr ... stock pressure is 43 psi.


The poster:

You need to do some logging. You can't tune using a butt dyno or the guess method. Log your rpm, timing, O2 for the high throttle and for low log your ltft, stft, rpm and if you want to you can log O2 as well but it's only needed to get an idea of where you need to be at. Either put your stock injectors on and set the afc at 0 or find someone that knows how to use it and have them tune it for you and teach you.

 

[adam355]

You need an aftermarket fpr ... stock pressure is 43 psi.


The poster:

You need to do some logging. You can't tune using a butt dyno or the guess method. Log your rpm, timing, O2 for the high throttle and for low log your ltft, stft, rpm and if you want to you can log O2 as well but it's only needed to get an idea of where you need to be at. Either put your stock injectors on and set the afc at 0 or find someone that knows how to use it and have them tune it for you and teach you.

My problem before was that i couldnt tune/log hi throttle period because the car would bog down so bad the second I hit high throttle.


For everyone else thats been helping me: I made a big dumbass mistake of leaving the stock injector insulators in the head and just realized that when I pulled the 650s. So I took those out and put the 650's in again, but there was a loud hissing leak in the first injector. So I ordered new bottom insulators and o-rings off roadrace. Hopefully my problems were due to doubling up the bottom insulators. When I get the new seals on the 650s I'll come back to this thread and tell everyone where Im at. Thanks for the help I'v received so far.

 

[Revolution]

Im just curious , you didnt happen to leave off the vacume hose on you'r afpr when tunning the afc did you.

Most if not all aftermarket afpr like the aeromotive are progressive types of regulators always adding and subtracting a pound of fuel per pound of boost.

Now to my understanding by keeping the base fuel pressure you could lean out the afc enough to let the afpr adjust the fuel suply phisicaly enought for things to even out.

Now I may be wrong (so I will cross refrence this info just in case) but the leaner you go the more timing you would get thus robbing you of power. they way I was told to set up the base pressure with the vac line off , then replace the vac line on and lean out my 650's .

I ran my car well on the old setup , but now I have to do it all over again for this evo3.

I'll let ppl know how im progressing , sometimes patience is my last virtue.