A noob afc question

[white90gsx]

Well Ive read the AFC tuning guide and don't understand it..It say for lo thr adjustments to hold an rpm and then adjust according to sounds in the exhaust they said you will hear miss fires or smooth but when I adjust nothing happens...

 

[mikelv]

Did you read the new one that I wrote? Because I didn't write anything like that.

I think you are referring to the one on Road Race's site?

Don't tune your car off exhaust sound man.....just don't.
You have a logger..... use the fuel trims outlined in the guides on here.

http://www.dsmtuners.com/forums/art...c-mid-point-correction-factors-operation.html

http://www.dsmtuners.com/forums/articles-tuning-ecu/58403-definitive-piggyback-tuning-guide.html

 

[white90gsx]

yea i have a logger...ok im gonna read these Ill let ya know whats up then.

 

[mikelv]

550cc Injectors, you should start around (-10%) across the board and fine tune the fuel trims from there.

All the information you need about the AFC is in those two tech articles.

This one will help you know what's going on as well.....don't over-think it, it's actually a one dimensional (pretty simple) device. No 3D maps or anything like AEM....easy stuff.

http://www.dsmtuners.com/forums/articles-tuning-ecu/105569-how-safc-works.html

 

[mikelv]

yea i have a logger...ok im gonna read these Ill let ya know whats up then.

With the 1G, your looking to get your fuel trims as close to 100% as possible. (+/-) 5% is ok. It's all in there man. If you have any questions after you read it.....read it again.

Then if you still have questions, post on back....no problem willing to help ya out. We'll get er right. Good Luck, keep us posted.

 

[white90gsx]

Ok will do...

 

[white90gsx]

Well when I start at -10%(550 injectors) correction the car bucks and misfires until I put back at -18%. I want to start there like the post says.

 

[mikelv]

When you try and calulate for starting points, it's a little different than DSMLink. Since the AFC just intercepts a signal (airflow) the compensation table is different than the straight forward adjustments (fuel) with DSMLink.

Go ahead on your low tables and start at (-18%) if that's where the car likes it. Then take a logger and see where your fuel trim numbers are.

Are you logging as you go?


The ECU is watching the airflow maps and trends, and from there determining injector pulsewidth. (Fuel flow) It'll take a few minutes to for the long term trims to change, so be patient. 3 - 5% on the logger is equal to about 1% on the AFC. Below 100% lean it out, above needs to be richened up.

 

[mikelv]

And also, don't open up the car when were untuned at this point! There's no need to until we get things correct and you get a better understanding of what's going on. You're just going to break shit if you do.

 

[white90gsx]

ok cool Im going to tune today.

 

[white90gsx]

I was doing my new alt belt and timing belt so ill tune after i get back from the junkyard....

 

[white90gsx]

OK well everything was going good I started by adjusting the fuel trims closes to 100% as I can. Well I think I was doing it right..I started by setting fuel trim at idle then at 1k then at 1.5k(am I suppose to use the 1000 rpm setting on the logger for all idle 1000 and 1500? Well when I reved to 2000 the fuel reading said 104.7% then stayed there and wouldn't move no matter what i do. Also am i suppose to use the 2k setting on afc for 2k(i would think) or what I don't understand? Even after I would change everything out of wack the logger still stayed at 104.7%....Im pulling my damn hair out..

 

[white90gsx]

Also today I turned the boost up to like 20 psi but i got like 37 counts of knock and it bucked back and forth i don't think i hit fuel cut ...when I tune it will it allow me to add more fuel were i need it to so Im not knocking?

 

[CanadianTSi]

Yes, as you rev the car to a certain rpm, say 2000 you want to tune the 2000rpm slot on the S-AFC. Also sometimes the fuel trims can take awhile to update.

 

[white90gsx]

ok i went out to take another shot and what am i suppose to do for idle 1k and 1.5k..i got all the way to 3k and the mid fuel trim moved for 3 sec then stopped at 104.3 and dint move.

 

[mikelv]

Hey man, sorry it took me so long to get back to you.
I can't log on to Tuners at work anymore.

You getting the hang of things?

 

[mikelv]

Also today I turned the boost up to like 20 psi but i got like 37 counts of knock and it bucked back and forth i don't think i hit fuel cut ...when I tune it will it allow me to add more fuel were i need it to so Im not knocking?

37 counts of knock is like 10 degrees of retard, that's not good man.

You need to tune the A/F ratios correctly and then turn the boost up some.

Turn that boost down and don't do that again!! Your going to blow shit up man.

Tune at around 14-15psi so if you do get some knock, it's not going to be pushing that hard. Once you get things running ok, you can tune on your setup safely at 19 psi. Don't go above that on pump gas.

When you tune wide open with any Wideband, log your front O2, and timing. You should see a healthy time curve to about 16 degrees, and watch the pull, if you see it pull timing, that's the ECU's way of avoiding knock.

Your O2's should be no less than .94v but I think 1G's can tune for .92v. I'm going to look that up for you, or someone else chime in to back me up here. I don't think it's safe to go any lower or leaner than that.

What were you're high settings for that pull? Turn the boost down some and try again, you're going to knock on your setup with that much boost and pump gas....

 

[mikelv]

You can get a pretty simple tune on an AFC with 550's.

Basically, you can add fuel to avoid knock, but that will only get you so far when running higher boost levels.

Pump gashas a low burning point, so when you add more air, it's going to get hotter and explode sooner, causing you to knock. Read some of my posts in this knock thread. Plus some other guys, good info here...

http://www.dsmtuners.com/forums/tuning-engine-management/305330-knock-question.html

I agree as well.

Every car might be different, but 15 degrees of knock is insane. You're playing with fire with that much knock on any motor, stock or built.

The main reason why I prefer DSMLink over AEM is for the simple fact that you can retain many factory settings including the knock sensor. On a 2G the knock sensor is very sensitive, and picks up just about any vibration. Heck when I turn the boost up over 30psi, I always get a reading of .4 deg to .7 deg of knock just because it’s making so much power. I like that sensitivity, it keeps me in check. When you start making big power, you need to be very carful of what you’re doing. Also, I like the feature of changing the stock boost gauge to read knock….works well for me.

Engine Knock:

Think of engine detonation as going against the grain when you’re shaving your face. What happens? You cut yourself and get bad razor bumps the next day when the hair grows back. Bottom line, don’t do it, you know what’s going to happen.

If you guys are tuning for knock, you are going against every principle of the internal combustion engine. What is happening is better understood as “pre-detonation”: The act of the mixture combusting before it was intended to. I mean we can get quite complicated when talking about this subject, but I’ll do my best to keep it simple.

When an engine knocks, you’re causing the engine’s pistons to travel in the opposite direction that it was intended to during the cycle. Meaning when the 2nd and 3rd pistons/combustion chamber are on the compression stroke (for example), and the fire starts too soon for what reason, you force the piston back down too early. Well this has a domino effect on the whole rotating assembly because last time I checked; all four journals are sitting the pistons on the same crank shaft. You make 2 and 3 shoot down too early, and violently vibrate out of direction (my example of going against the grain) then 1 and 4 are going to be negatively effected as well.

There are many factors that attribute to the cause of an internal combustion engine pre detonating, including gasoline, thermal efficiency, environmental conditions, exceeding prescribed volumetric efficiency (i.e.: excess boost/airflow), ignition system malfunction, excessive timing advance, and among others, and probably the most dangerous of all, a loose nut between the steering wheel and the driver’s seat/ head rest.

Gasoline has a certain burning temperature and the lower the octane (generally w/o additives such as Meth or NO2) the lower the burning point. The higher the octane (race fuels/ premium fuel) the higher the burn point, meaning the higher the burn point, the more air you can force induct, and essentially, the more energy you can produce to the crankshaft and essentially the transmission and drive wheels.

I could go on about the rest, (which I’ll probably end up doing anyway) but the bottom line is there is no benefit to pre detonating your engine. To force your pistons up and down before they were intended is not going to give you record breaking power; just breaking power.
Well maybe for some right? But it’s really not worth it for most of us. Tune for safety and efficiency, because IMO efficient power is effective power. There is the top 1% of the guys out there who tune for this stuff, but it’s not in the cards for everyone.

I suppose if you want to call it matter of opinion, then once again I suppose you have a passion for re-building engines.

 

[mikelv]

You get out on the car tonight?

 

[white90gsx]

NOOO..You completely miss understood me my current boost setup it 15 psi and sometimes I'll get 1 count of knock but not always.I turned it up to see what kind of knock I would get...The problem I'm having is with the tuning process I don't know if its a defective logger or whats going on..But my mids and highs fuel points are no working on logger there stuck at 100%..They are there but they don't move when I press in the gas.

 

[white90gsx]

OK listen I seriously need to speak with someone on the phone about this...None of my fuel trims are changing except the low trim and what am I suppose to do hold the car at 3k for 2hrs for the mid trims to start and adjust there's got to be a different way to do this..How the hell do I run 19psi just by adjusting it tomorrow is the last day for the track and I want to end the season with a good time..For 19 psi what correction do I set the trims at and what rpms..Im sure your going to say every car is different well throw me a fickin bone here() because I don't even know were to start..My car runs like shit now that I adjusted my ftrl close to 100% the car runs excellent at -18% why cant I just add fuel to help with my boost?

 

[talon96tsi]

there are no universal settings. there are many factors here. your air desity, altitude, air temperature etc. are all going to be acting upon the car at that time. that is what the logs are for. the logs will tell you specifically what you need to do. as stated before, 19psi is nowhere to safely start. 37 counts of knock is insane. your long term fuel trims are not necessarily going to change at all. long term trims are stored by the ecu and used for startup and long term adjustments. short term trims in closed loop is what you need to look at more closely, they are whats going on at that specific time.

 

[white90gsx]

there are no universal settings. there are many factors here. your air desity, altitude, air temperature etc. are all going to be acting upon the car at that time. that is what the logs are for. the logs will tell you specifically what you need to do. as stated before, 19psi is nowhere to safely start. 37 counts of knock is insane. your long term fuel trims are not necessarily going to change at all. long term trims are stored by the ecu and used for startup and long term adjustments. short term trims in closed loop is what you need to look at more closely, they are whats going on at that specific time.

That does not help me..I know 19 psi is no were to start...WHAT DO I NEED TO DO TO RUN 19 PSI? Im following the directions but nothing is happening and my fuel trims are not changing. I have fuel reading on my logger ftrl-ftrm-frth thats what I have no long term or short term.

 

[mikelv]

Hey man, sorry I can't get on here too much the last few days.
Relax man,we'll work it out. I feel your pain, but the worst thing you can do is get fustrated.
trust me i know from experience. dont worry we'll get t right.

 

[mikelv]

OK listen I seriously need to speak with someone on the phone about this...None of my fuel trims are changing except the low trim and what am I suppose to do hold the car at 3k for 2hrs for the mid trims to start and adjust there's got to be a different way to do this..How the hell do I run 19psi just by adjusting it tomorrow is the last day for the track and I want to end the season with a good time..For 19 psi what correction do I set the trims at and what rpms..Im sure your going to say every car is different well throw me a fickin bone here() because I don't even know were to start..My car runs like shit now that I adjusted my ftrl close to 100% the car runs excellent at -18% why cant I just add fuel to help with my boost?

It can take quite a while on the trims, and they can be a pain in the ass IMO.
It's easier for me because I have DSMLink, so I have more control. I dont even run fuel trims, and dont even use an O2 sensor.
You can do this same thing, but don't stress man, we'll get her right. I'll give you a call tonight homie.