What to Log?

[Gooberlog]

What else can i log besides O2 Voltage to see how my car is running rich or lean at a given RPM?

 

[pneumo]

The fuel trims are the first thing I look at. Low fuel trim is used at idle and slow speed driving, approximately 25 mph and below. Mid trim is around 25 to 45 mph. High trim is freeway driving up to 75 mph or 3750 rpm, which is where the ECU switches to open loop mode and stops using the fuel trims. Also look at O2 trim because that's the instantaneous trim. Of course you should also log throttle position and rpm so you know what to adjust on the AFC.

For more details check out www.VFAQ.com/TMO/

 

[pneumo]

Oh yeah...

Try to get the trims around 100% to 110%. That seems to be where it runs the best. If the trims are above 100% that means the car is lean, so add some fuel with the AFC.
Below 100% is rich, subtract some fuel.

 

[Gooberlog]

Ok, i'll log some runs on the trims and see how they look. I have my AFC in my room waiting for me to put in, but its cold as hell.
Another couple questions- i my car will hit about 38!! counts of knock in the higher rpms past 5300rpms but 0 up until about 5k, but i think this is bc i have no fuel tuning right now and at the higher rpms' uneder WOT my car creeps from 16-19psi. Would this boost creep cause a lean condition in the higher rpms which could be causing my KNOCK ? Also yesterday with the logger hooked up, under normal driving at about 3400, maybe 3-6psi my car got 15counts of knock in 1st gear. Do you think that i'll just have to richen up the low trims and lean out the high trims once i get my creep taken car of? What should i look for on my trims to verrify this? Thanks for all of the tunning help.
Travis

 

[pneumo]

The fuel trims are not used at WOT. For WOT tuning just look at knock, timing and O2 volts.
The AFC has Hi and Lo throttle settings so you can tune the fuel trims with the Lo map, which are used at daily driving speeds, then tune the car at WOT with the Hi map.
The boost creep is most likely making the car run lean at higher rpm, which leads to way too much knock. An upgraded fuel pump would help, too.

 

[Gooberlog]

I'm not sure if it lieft it out in my signature but i have a Walbro 255pump.So your saying for WOT tuning just tune lean enough until i start to see knock and then back off a tad? What % increments should i lean or richen the afc when makind adjustments? I think i read the .92 volts from the O2 reading is optimal for WOT, is this right? When tuning for the low settings do i mainly look at the "Fuel Trim Lo" and for Hi Trtl. Settings on the afc do i mainly watch the "Fuel Trim hi" I think i read somewhere that you want the fuel trims to be between 100-110%, do you agree. Sorry about all of the Tuning questions but i'm a tuning Newbie. Thanks for all of the answers!!! I'm gunna watch the weather and try to put my afc in on the warmest day coming up.
Thanks
Travis

 

[pneumo]

You're starting to get it. Look for knock and O2 volts at WOT, but don't bother looking at the hi fuel trim at WOT, they're two totally different parameters. The Hi trim is used under part throttle driving at freeway speeds. After you go WOT the ECU stops looking at any of the trims.

Don't try to hit .92 volts just because someone said so. You already have a better way to tune; get rid of knock. Since you're already getting some big knock counts at higher rpm just add more fuel in the hi throttle map at the rpm points where you see knock. It usually takes 2-4% to notice a difference. Then, after you get the knock down to 5 or less, check the O2 volts to see where it is. That is the O2 volt # you should tune for on your car.

On the AFC the Lo throttle settings will adjust all of the fuel trims.

The Hi throttle settings are used for WOT.

 

[Gooberlog]

Well my friend helped me out and basicly put my acf in my car, but when i took it for the test drive, i was getting a steady 43knock on the loger from 2K-5K in every gear!!! needless to say the timing was being pulled. But something else i noticed, was that my logger wouldn't let me log a run durring the test drive??? I played with the lo throttle adjustment on the afc while crusing at 2600rpms in 1st gear with the knock steady at 43, but even when moving the fuel from 0-+50%and all the way down to -50, nothing was happening to the knock, steady at 43?? Also when i left his house, my palm M105 froze up with a fatal erorr code saying "Memory Mgr. c,Line.3036, Chunk over-locked" There were about 1/3battery life left. Once this happen my logger was unusable, i'll probobaly have to pull the batteries and hotsyn the program. But on the way home, i'm sure it was kocking, my a/f gauge was pegged on RICH while crusing at 3K at 70mph, and my turbo timer "apexi" was reading .98-1.00 o2 voltage while cruising/exhuast was sputtering, if i floored it, the car would bog, and then spool-up to .92, i tried leaing out the lo and hi on the afc while cruising home -15%,but then under WOT the o2 voltage dropped to .88 so i backed off and zeroed it out again. It seems like the car is just running rich as possible at low and hi throttle. Also while we were installing the AFC, i unpluged the ecu connectors, and one they were undone, i disconeted the battery terminal NEG. Do you think this is bc the battery terminal was disconected after the ecu was unpluged or was the afc installed wrong or niehter? Before the afc was installed i was getting about 15counts of knock in 2gear only about 3k rpm, otherwise not much at all. PLEASE HELP ME THANK Pneumo and others!!!!

 

[pneumo]

Say No to Drugs
Stay In School
Dont let friends install AFC!

Something is messed up, that's for sure! When the AFC is zero'd out it should run just like before you put the AFC in. But yours didn't run good at all. So try double checking everything- all the settings on the AFC, not just the Hi/Lo throttle %. Then re-check all the wires to make sure they were done exactly like the instructions say. Also check out VFAQ.com and read the AFC installation guide.

It's OK to unhook the battery, it won't mess up anything.

 

[Gooberlog]

Also once i reconected the battery and started the car i had to adjust my BISS. I will make sure the Hi and Lo settings are set to 0% , and from there i'll check the wiring. VFAQ.com's site has had a dead link to the afc install for as long as i've had my car. I haven't really found a good pictoral instruction site. My frined that put in my afc just installed a afcII in his 93gsx but it got stollen the next day. ...although he had a cople beers, i guess i'll just check the wiring agian, and site where i just looked at a picture of a properly installed afc? Thanks for all of the help, i'm hoping that its just a wire somewhere, Also i had to remove the batties from my palm so i'll have to hotsyn POCKETLOGGER back onto it now. WHAT A HEADACHE, any other suggestions?
Thanks alot
Travis

 

[pneumo]

You might want to read the AFC set up guide at www.RoadRaceEngineering.com/newafcsetting.htm

Then look at the AFC tuning guide at www.RoadRaceEngineering.com/newafc.htm

Print the page and take it with you to the car. Go over each step one step at a time. Make sure you understand what you're doing, don't guess.

 

[Gooberlog]

My airflow wires were wrong, i used the wrong wires from the afc, but now that the cars running right 'for the most part' the airflow% on the afc is 0% at all times, but my pocketlogger shows 1606hz when i log it at WOT. Any ideas on that one?
Thanks
Travis

 

[pneumo]

Glad to hear you got it sorted out.

1606 Hz is the highest the logger can read, so don't worry about it. The MAF and ECU can still read higher Hz. If you need to see how high the Hz is going you can read it from the AFC, it has a peak hold function built into it. To see it, go to Monitor, make sure Airflow Hz is selected, then go to the numerical monitor display. After a run, click the "up" arrow and the highest readings will be displayed. This is also handy for seeing peak rpm, throttle position, etc.

 

[Gooberlog]

Well the car seems to be running now, My boost is set to 16psi but USUALY creeps to 19 "racepipe is overflowing stock wastegate flapper". On tonites final runs, the boost crept to 17psi solid "Thumbs up" After final adjustments i added 7% at 7k and a little less in the lower numbers. After these adjustments were made i only picked up 3 counts of knock through out the whole run. Although my high end numbers have benifited with the afc, i'm getting a lotttt of kncok "43" starting at about 2k rpm's under light throttle. I'm not sure if this is phantom nock or what, but either way my timing is being yanked bc of it, i only get this knock intermitently. Thanks for all of the help and and let me know what you think.
Travis

 

[Gooberlog]

By the way i hooked up the wrong wires from the afc to the airflow because me and my friend were originaly using the afc instructions for the HOTWIRE sensor.