chillin014

iTrader: (67)

I just tried again and no matter whether I add or subtract fuel the A/F logs are practically identical.
I am on the Wide throttle HVT map when making my corrections... vafc appears to be set up correctly.
I am confused.
All help is appreciated.

I can rule out my wiring since the car runs perfectly normal, right? I mean it wouldnt work otherwise..plus I was very careful in wiring everything up.

NiZMo1o1

iTrader: (45)

you may need a tach adaptor , I was told I need that before I can run anything safc or vafc on a 6th gen max.

chillin014

iTrader: (67)

Hmm I've never heard of that/don't think that's required on my car but I'm going to confirm that asap.
Thank you! This is irritating!

gtr_rider

iTrader: (50)

Did you follow the writeup exactly, make sure you got all the wiring especially the MAF as it is somewhat easy to mistake a wire for another and snip the wrong one.

95BLKMAX

iTrader: (10)

No tach adapters needed for the A32/A33/ and AFAIK A34 ECUs.

sunstream453

yeah, no maximas as of yet (thats 6th gen included) need a tach adapter. chillin, try changing the in/out values while the car is running and see if it makes a difference. if not, then you either have a bad vafc or have cut the wrong wire (IE: not MAF wire). if it does make a difference then you just need to make a bigger correction. have you checked to make sure that the RPM the unit is reading matches the RPM you are actually at? just go to the display section and select the tach, then rev it up and see. if not then there is your problem

chillin014

iTrader: (67)

thanks for your replies.
I will check to see that I have cut the right wire...I am fairly sure I did though because once time it was making a poor connection and the car stalled out or acted real funny at start up.
The rpm matches fairly well...sometimes it seems about 100 off. I took a good 15+ percent out when making my corrections all across the power band (3k to 6500) and it showed zero effect.
If I have a bad VAFC then I have the worst luck of anyone I know...it seems to function normal otherwise.

and yes I followed the write up exactly. I didnt stray on my own for anything really except that I had to solder a new harness onto the vafc (previous owner cut it off for some stupid reason). I was very careful during all of the wire matching though...everything was color coded. My vafc does read the "map" percentages from the MAF as well.

chillin014

iTrader: (67)

I'm reading over the write up right now...and saw this "Take note of subscript on ECU harness image for the location of Blue(O2 sensor hookup wire)"
I didnt tap any 02 sensor wires...why would I?

the blue wire is the "vtm" signal apparently...reading...The installation manual for the vafc doesnt show it being tapped into but rather cut completely and only reading from the vafc. I havent done anything like that with that wire.

also...I may have the wrong MAF wire...its pin 54 on vq power and in the fsm alike but the color should be B/Y blackyellow? and mine is definitely not..its like white with a black stripe. For my sake I hope this is the solution...but now I'm wondering what I actually DID tap if thats the case and still curious about the VTM wire.

sunstream453

you dont need to tap any o2 wires. i would suggest checking a pin diagram for the number location and forget about color. anytime i tap an ECU wire i always verify that the wire im cutting is coming out of the specified pin location. its too common that you find a different color wire where x color wire ought to be.

chillin014

iTrader: (67)

so the VTM is unnecessary then? something vtec related i guess.
I'll check the wire again tomorrow morning...I really cant imagine I cut the wrong wire though.

chillin014

iTrader: (67)

it looks like I've got the right wire tapped...its not B/Y its white with gray dots on it like a lot of the surrounding wires but it IS the 54 pin as shown on the diagram....

sunstream453

have you checked to make sure that the RPM lead is reading and responding?

kzoosho

iTrader: (16)

Did you splice the maf wire or tap it? you are suppose to intercept it not just tap it other wise your corrections mean nothing.

chillin014

iTrader: (67)

It is reading rpm fine, I can see it while I'm driving under monitor mode. The maf wire is intercepted not tapped.
I'm going to try to make corrections on another map and see if it makes a difference...I have a dyno day to attend on saturday (not a dyno tune) and I wanted to have this done.

kzoosho

iTrader: (16)

Ok i was just makin sure. Som just tapped the wire and that will do absolutely nothing.

chillin014

iTrader: (67)

can anyone confirm that their maf wire was a white wire or something other than the color specified in the FSM? I realize it differs from year to year but it just seems like the maf wire would be one of more significance or easily definable rather than looking identical to 4 surrounding wires.

xraver_px

iTrader: (8)

hope this helps, scroll down and click the ecu pin out thumbnail

http://www.vqpower.com/v2/readarticle.php?article_id=98

chillin014

iTrader: (67)

yeah....that IS the write up.

chillin014

iTrader: (67)

Okay. I decided to monitor the "pressure" mode on the vafc2 on the way home tonight in order to see what it was reading. I realize these numbers dont mean a whole lot but for comparison purposes maybe they will be able to confirm I've got the right wire tapped. Under zero throttle including idle it reads -75kPa and under very light throttle usually still in the negatives but more around -35kPa~ for say 5% throttle depending on the rpm etc. Under WOT it seemed to max out at about +100kPa..but I only tried this once.
can anyone confirm these numbers are correct? if so...then I've obviously got the right wire tapped and we can rule out all of that mess.

sunstream453

well, it depends on if that is reading gauge pressure or actual pressure. when youre WOT you should experience near atmospheric pressure (its a little lower just cause the intake isnt perfect) which is i think 101.35 kPa, so your WOT value is right IF it is actual pressure. also, the other pressure could be right too because you are in vacuum at idle and part throttle conditions, which would read as a negative if there is enough vacuum. i didnt realize that the vafc would display that value, it doesnt on mine i dont think.

chillin014

iTrader: (67)

very interesting and thank you. I didnt realize it was that simple I guess..I was told these numbers meant nothing because they were supposed to be reading off of a MAP sensor. But none-the-less it looks like I've got the correct wire tapped and the vafc IS getting that signal and therefore relaying it through to the ECU. (right?)
so now the question is...why wont it make the corrections...
tomorrow I'm going to play with a different map and call Apexi and listen to them tell me I installed it wrong or something. They'll probably think I'm an idiot for installing a Vafc on a Maxima.

chillin014

iTrader: (67)

I am having no luck with this. I called up Apexi and the guy basically told me what I expected him to tell me. "Its not meant to read hotwire thats why it wont make the corrections."
I feel like I should just buy a damn SAFC but then thats a total waste of money because I cant really sell it as a working unit if I didnt get it to work.
VAFC2's work on A32 MAF's right?!?!

gtr_rider

iTrader: (50)

I am currently using a VAFC2 on my A32 with stock maf ..

95BLKMAX

iTrader: (10)

gtr_rider, do me a big favor, can u post all the non-correction-related settings you have on the VAFC? I've been trying to help him over the phone with the settings but there's only so much I could do given off what I REMEMBER from Dala's and Ernie's VAFCs when they had em, lol.

And also can you confirm the actual map where you are making the corrections. it should be the high/wide map w/e thinggymajig

chillin014

iTrader: (67)

thanks guys. I just dont understand...buying a new/different unit is my "last resort" but I've pretty much ran out of ideas at this point..

gtr_rider

iTrader: (50)

CLEAR SETTINGS
===================
1. Turn IGN. to the ON position but DO NOT start the engine
2. Navigate through the menu's (ETC>>Initialize, and toggle over to Yes).
3. Accept the choice, wait 5 seconds and turn the ignition to the OFF position.

INITIAL SETTINGS
===================
1. Turn IGN. to the ON position but DO NOT start the engine
2. Navigate through the menu's (ETC>>)
3. Enter Settings:

Sensor NO: 4IN, 4OUT
Car Select: 6Cyl, Arrow UP and Right, V/T 1
Sensor Chk: Make sure its reading +/- 0.500V(closed TB), +/- 4.1V(WOT)

4. Turn IGN. off, wait 5 seconds and turn IGN. on
5. Wait 10 seconds and depress pedal 100% for 10 seconds.
6. Start the car.

VI SETTINGS
====================
1. Turn IGN. to the ON position
2. Navigate through the menu's (Setting>>)
3. Enter Settings

Narr. Thr/Wide Thr: (Make sure these are set to 0%, if not redo CLEAR SETTINGS)
V/T Cont: L>H (varies based on dyno ie. 5100), H>L (varies based on dyno ie. 5000)
TH-Point: Lo(35%) Hi (70%)
Ne-P:Hvt: Spread out RPM range 5100-6500
Ne-P:Lvt: Spread out RPM range 3000-5000

chillin014

iTrader: (67)

I'm not using a VI but I see you have the high and low maps different from mine already. I have my Hvt-wide map starting at like 3kand going up to 6500. Should I be adjusting on the Lvt map?
also what is the V/T about? Do I need any of that if I'm not running a VI? what do you mean if varies based on dyno?

is it possible that because I dont have any of that vtec **** turned on its simply not making the adjustments because maybe its not going ever reading from that wide-hvt map?

thank you!

also, my throttle voltages are probably a bit off since I never could get it right with my PF TB but it still reads the percentages properly it seems.

gtr_rider

iTrader: (50)

If you are only working off the Hvt-wide map than you are pretty much using only half of the tuning points that the VAFC offers. Reset the map so that 3000RPM-"switchover" are on Lvt and "switchover"-6500RPM are on Hvt. The V/T setting is for "Vtec Type"

Level 1 gives us the broadest RPM range (3000-7000RPM) of tuning.
Level 2 gives us (3000-6000RPM) of tuning.
Level 3 gives us (2000-6000RPM) of tuning

chillin014

iTrader: (67)

but I'm not tuning under partial throttle...since from what I can see it seems to stay pretty stoich under 50 percent throttle or thereabouts.
So what would I need to spread/split it over two maps for?
I guess what I'm confused about is...what the lvt-wide map does exactly. Is it for lower rpms when the throttle is open 70percent and over (as your throttle settings show).
If I spread it fromt lvt to the hvt map is the benfit that I would be giving myself smaller increments to tune within?

mowgli29

iTrader: (21)

From my understanding, yes. You'd have 24 points of correction as opposed to 12. Therefore, you could make adjustments in smaller incriments and hopefully that would result in a smoother a/f curve. That's my understanding of it....correct me if I'm wrong.

NmexMAX

iTrader: (22)

No one said you were.

Which is why we let the ECU do it's thing below ~40% throttle.


For added resolution (more RPM tuning points). You can have all 24 correction points @ high throttle.

Exactly. Lvt / Hvt have nothing to do with throttle, if you set the throttle the same (70%), it has to do with RPM.

I know you've seen it, but here it is again:
http://forums.maxima.org/showthread.php?t=345841

mowgli29

iTrader: (21)

so open loop is triggered by two things: rpms above 3k, and +50% throttle.
does the ecu go to open loop when it sees either of these? or do BOTH conditions have to be met for the ecu to go to open loop?

NmexMAX

iTrader: (22)

http://forums.maxima.org/showpost.ph...4&postcount=87

mowgli29

iTrader: (21)

Alright, I've gotten alot of conflicting info about open loop/closed loop and part throttle tuning. Going by this post, however, tuning below 3k and part throttle tuning WILL have an effect and CAN be beneficial. Tell me if I'm understanding this incorrectly...

EDIT: trying to piece together bits of info...tell me if this is right:
even though it may be in open loop under 3k or at part throttle sometimes, the ecu still does well enough to maintain stoich. but under full throttle and higher rpms, the ecu does NOT do well enough....is that the reason for no part throttle and <3k tuning?

NmexMAX

iTrader: (22)

If you're WOT and using an AFC, then adjusting below 3500 RPM will affect your AFR below that RPM.

But trying to 'fine' tune using the throttle settings, IMO, doesn't work to well since the ECU does a good job when under light load, etc.

It's WOT / high load that the ECU starts going into a weird, typically rich setting.

mowgli29

iTrader: (21)

apparently I edited my post at the same time you posted this...anyway, I was thinking along the same lines. Thank you!!! I FINALLY have a definitive answer.

gtr_rider

iTrader: (50)

I would venture to assume that both parameters have to be met for the ecu to go into open loop.

NmexMAX

iTrader: (22)

The entire thread from the link I posted covers this to a great extent, and IMO, eng92 hit it on the head.

This page has most of the info from which I base my opinion from. Coupled with my AFR readout / throttle position, etc.

http://forums.maxima.org/showthread....64#post3971664

gtr_rider

iTrader: (50)

NmexMAX

iTrader: (22)

Not mine