Questions about tuning for DE-K injectors

[DAVE Sz]

Originally Posted by NmexMAX

http://forums.maxima.org/showpost.ph...7&postcount=87

headlights?

Originally Posted by steven88

http://forums.maxima.org/showpost.ph...3&postcount=91



check this out too...quoted by nismology

rsb?

Originally Posted by NmexMAX

I still think eng92's hard/factual data is better.

Any chance of these being fixed to show what you guys actually wanted to link to?
Seeing different suggestions in every VAFC thread and want clarifications

[DAVE Sz]

Originally Posted by steven88

yes you could start at 3000 and go in smaller increments...the way sr20den sets his up is becuz he has larger injectors and a larger MAF....if you are stock, then you wouldn't really need to modify the low RPM/low throttle settings...

if you have simple bolt ons, starting at 3k would be just fine as well

But since we can't adjust anything below 3kr rpm, closed loop, why would he have changes there? Unless of course it's for WOT which would then be high throttle not low throttle right? I'm confused and wanted to contact SR20 but he's not accepting PM nor has he been online in a few weeks...

[MDeezy]

Originally Posted by DAVE Sz

But since we can't adjust anything below 3kr rpm, closed loop, why would he have changes there? I'm confused and wanted to contact SR20 but he's not accepting PM nor has he been online in a few weeks...

confused about what?

cant make changes sub 3k due to closed loop. (maybe pm streetzlegend who pulled his o2s to force the ecu into open look all the time).

but @3k you can make changes so make your increments from 3k+ that way you, can have a smooth power line...

[DAVE Sz]

Confused about sr20 adjusting his vafc starting at 1200. steven said he did that cause he had larger injectors and maf so he also tuned his low rpm/low throttle settings. To me that sounds like he made adjustments to closed loop. But from what I read it sounds like he adjusted his WOT settings starting at 1200rpm. Or is it just since the lvt and hvt points don't intercept they are simply 24 different WOT points?

[MDeezy]

oh I missed that part. We'd need him to chime in to help clear that up. Its never beed defined but a lot felt if your at WOT you in open loop regardless of rpms. if this is true then it shatters the whole 3k thing...

[DAVE Sz]

I'm trying to figure out how to take away fuel at idle and low throttle due to my de-k injectors. His post seemed to hint that he used the vafc2 to take away fuel starting at 1200 instead of 3000(open loop)cause he had larger injectors. Where of course I'm now thinking it's all just WOT talk...

[DAVE Sz]

So I was thinking. Googling vafc and closed loop I read that if you adjust "closed loop" with the vafc, the AFR changes for a few seconds then goes back to ~14.7. Now does it go back because the ECU ignores the changes or because the ECU compensates for the changes, in order to get back to stoich? For example, if I take away 5 "points" of fuel does the ECU just ignore the signal or does it see that fuel was taken away and compensates?
After all the stock o2 get afr from what goes into the engine and the ecu uses them to get 14.7...
I'm probably wrong but....

[nismology]

It compensates for the changes.

-----------------------

SR20DEN probably set the first RPM site that low for more favorable interpolation between his low and high maps or within the maps themselves. Probably a smoother transition between closed loop and open loop that way; especially with a larger MAF housing/larger injectors. You should contact NmexMAX though. He's had experience using the V-AFC II w/ larger MAF's.

[DAVE Sz]

so technically, we can adjust closed loop, we just don't know what we're changing it to since it always goes back to 14.7. That means I can take fuel away starting at idle and sort of tune it. I would just need to check how much fuel I'm pulling.

[nismology]

The ECU can adjust the AFR to stoich, within reason. It can't, for instance, completely compensate for a vacuum leak. Which brings me to my next theory:


IIRC SR20DEN disconnected the front valve cover breather from the intake tract. Doing so creates a vacuum leak that needs to be tuned out manually. Perhaps he was adjusting for this. In any case, for most basic setups closed-loop tuning won't be possible, let alone necessary.

[DAVE Sz]

with the de-k injectors I would need to pull fuel throughout the rpm range. I'm not exactly sure how the VAFC works but if I take away fuel do the injectors just flow less or is the injector pulse just shortened?

[nismology]

Injector flow at a given fuel pressure is static so it's the pulse width that is shortened.


What's your current AFR looking like?







*I almost feel like this deserves it's own thread.

[DAVE Sz]

AFR is wonky at best, looked to be in the 10.5-11 range the 5 or so seconds it was in open loop. Put the sensor in today but haven't had time to drive the car since just swapping a z32 maf in and out has made the car almost inoperable after all was put back together. So if I fix it today I should have most of the day tomorrow to go out and do some logging...

[nismology]

Was wondering more about the closed loop AFR since that's what I was referring to at the end of post #67. The ECU should adjust for the larger injectors in a closed-loop scenario.

[DAVE Sz]

it does and close loop is around 14.7. I guess my question would be how does the ECU get the AFR back to 14.7 when it sees more fuel than usual? If it was running lean it would keep the injectors open longer to let in more fuel. If it was running rich it would shorten the pulse width right? So in both situations the same amount of fuel is being used. Which means no real need to adjust closed loop as the fuel economy is unchanged, right? Or does closed loop work differently?
With the z32 maf, it was sitting around 16.x at idle but now I'm thinking that's because I didn't change the VAFC in/out settings to 2/4...

[nismology]

Originally Posted by DAVE Sz

it does and close loop is around 14.7. I guess my question would be how does the ECU get the AFR back to 14.7 when it sees more fuel than usual? If it was running lean it would keep the injectors open longer to let in more fuel. If it was running rich it would shorten the pulse width right? So in both situations the same amount of fuel is being used. Which means no real need to adjust closed loop as the fuel economy is unchanged, right?

You got it.

[DAVE Sz]

I guess that further confirms that this 40k mile engine I have is just a POS. 2+ years after acquiring it, I found out it was dropped down a flight of stairs. That would explain why it burns 3 quarts every 1000 miles...

[DAVE Sz]

At what throttle % does open loop kick in? Years ago I remember Ben, where did he go btw, wrote it was 70%. Was that proven?
I'm trying to figure out the TH-POINT settings in the VAFC, 2-SETTINGS->6-TH POINT. Should I set it to lo-70 hi-71? If I do that what happens when I'm at like 20% throttle and above 3k rpm and open loop kicks in? Or should I just set it to something like LO-25/30 HI 68 or so. I've read 10-90 but that no longer makes sense...

EDIT:
Nevermind, found this:
350z IM on fwd maxima
I'll just set mine to lo39 hi40 and be done with it...

[ajcool2]

Damn and I just did some adjustments on my VAFC-II to get better gas milage. I guess the better fuel economy is all in my head lol.

[shadyonedeath]

Got my 00vi dyno'd today with surprisingly low numbers...even being stock exhaust and all. Around 149hp with the mid range at around 13.3-12. 3-4k was around 11, and 5400-6500 was around 12-13 too. AFR is a bit jumpy but it was just a rough dyno-tune. (base line but they let me adjust for 5 pulls)

Kinda disappointed. Ill post up the graphs when they email them.

[MDeezy]

Originally Posted by shadyonedeath

Got my 00vi dyno'd today with surprisingly low numbers...even being stock exhaust and all. Around 149hp with the mid range at around 13.3-12. 3-4k was around 11, and 5400-6500 was around 12-13 too. AFR is a bit jumpy but it was just a rough dyno-tune. (base line but they let me adjust for 5 pulls)

Kinda disappointed. Ill post up the graphs when they email them.

Those are horrible numbers. a 4th gen stock with USIM pulled 170hp ish to the ground. Check for codes. Plus your jumpy AF is not helping. If your hitting 11s in some areas then something is definately wrong, Leaky injectors, bad o2 sensors, or you just need a tune! Even minus a tune your af should not be that rich.

please post the dyno graph up for us all to see.

[shadyonedeath]

Yea they're still handling their Dyno day so i probably wont get the runfiles until tonight. My graph was very jump. Ive read if its not flat the ECU trys to compensate and makes you lose power.


I doubt its a vacuum leak too. The only thing im worried about is not RTV'ing the rear valve cover. The gasket looked fresh and i didnt see a need to use any. I am getting a slight smoke appearance from the passenger/firewall side. Its not thick, just small bursts of smoke sometimes. The only thing i can think of is a oil leak... or either from spraying pb blaster on the Heat shield for when i get headers. But i rinsed the engine bay and its been 2 weeks now.


Lets see, here are my corrections from the 5th tune that yielded the most power increase compared to the 2nd-4th runs and closest to 13 AFR line.

3100-3900 - (-7)
4100 (-6)
4300 (-7
4500 (-8)
4700 (-10)
4900 (-9)
5000 (-8)
-----------SWITCH
5100 (-8)
5200 (-9)
5300 (-8)
5500 (-8)
5600-6300 (-6)
6400-6500 (-5)


I think i took off too much from the low end. We'll have to wait and see till the runfiles are sent.

[DAVE Sz]

Originally Posted by MDeezy

Those are horrible numbers. a 4th gen stock with USIM pulled 170hp ish to the ground. Check for codes. Plus your jumpy AF is not helping. If your hitting 11s in some areas then something is definately wrong, Leaky injectors, bad o2 sensors, or you just need a tune! Even minus a tune your af should not be that rich.

please post the dyno graph up for us all to see.

No Deezy. A stock 4th gen auto is in the low-mid 140hp area from what I remember reading 5-6 years ago. The 11afr does seem low. My full de-k swap doesn't run that rich.
Im running -3 across the range on my vafc as a rough tune that I know was safe and I'm still in the 12afr area across the revs. And you're supposed to use RTV even with new gaskets SHADY. Not everywhere but in the areas the FSM tells you to.

[shadyonedeath]

ill get on that next weekend.

[MDeezy]

Originally Posted by DAVE Sz

No Deezy. A stock 4th gen auto is in the low-mid 140hp area from what I remember reading 5-6 years ago. The 11afr does seem low. My full de-k swap doesn't run that rich.
Im running -3 across the range on my vafc as a rough tune that I know was safe and I'm still in the 12afr area across the revs. And you're supposed to use RTV even with new gaskets SHADY. Not everywhere but in the areas the FSM tells you to.

I was thinking more of the manuals than anything but Maybe about 160/165ish for an MT stock. they are rated at 190hp and there is that much drive train loss to bring the numbers down that much. Even a stock 4g auto should hit I'd say about 150-160 stock trim. But I'm going off old numbers and discussions. If there was a dyno to help prove this I'd love to see it. Regardless of what they do stock there is no power to be made with 11afs... even in 12's I'd think is too rich for N/A but truely a dyno and tuning will show what numbers are best.

Idealy most have gained good power with afs between 13-13.75 ish...

[MDeezy]

Originally Posted by DAVE Sz

No Deezy. A stock 4th gen auto is in the low-mid 140hp area from what I remember reading 5-6 years ago. The 11afr does seem low. My full de-k swap doesn't run that rich.
Im running -3 across the range on my vafc as a rough tune that I know was safe and I'm still in the 12afr area across the revs. And you're supposed to use RTV even with new gaskets SHADY. Not everywhere but in the areas the FSM tells you to.

I need to double check on the valve covers. Every time I did the 3.5 swap I'd use rtv when putting valve covers on. A friend was telling me you dont need it on the valve covers. Pull the valve covers off a 08 3.5 with 26k on it and saw no RTV on it... Didn't use any this past time sealing up the motor (just on valve covers) and so far so good...

But honnestly... if oil will be present, doesnt hurt to use it, but besides the valve covers just about every sealing surface needs rtv....(motor related).

[shadyonedeath]

1st run = 00vi Baseline. No adjustments. Activation point, 5100. (i know...i should of unplugged the vias)

1st run - HP vs AF

1st run - TQ vs AF

2nd run - HP vs AF

2nd run - TQ vs AF

3rd run - HP vs AF

[shadyonedeath]

3rd run - TQ vs AF

4th run - HP vs AF

4th run - TQ vs AF

5th run - HP vs AF

5th run - TQ vs AF

[shadyonedeath]

Overall - Torque vs HP

Overall - TQ vs AF


Overall AF vs HP

[shadyonedeath]

1)Seems like around redline, the richer it was, the more horse power was yielded.
2)Between 5700 and 4500 rpm, definitely needs to get leaner.
3) I cant speak for anything before 4400rpm, its an auto and 3rd gear. Is that dangerously lean?

[MDeezy]

good...this can help.

One thing..DAMN your TQ is falling fast!! I dont know if thats common but jeeze!

your red run is your worst run and on the same note thats when you were running very rich.

Your Purple run is your best run, and as you were making decent power you were between the 14-13af range...

149hp/163tq.... you can do better. Your A/F is all over the place. Check your ecu see if your throwing codes like o2 or KS. You definately need a tune. to adjust those wacky afs and see what power you get then. You have wideband do you have a tuning device? If so I suggest some pulls, datalog, tune, lather rinse and repeat.

You should feel the power as you straighten it out.

[shadyonedeath]

I have VAFC2, ordering lc-1 and obx headers as we speak...lol Still debating the headers though. I heard stainless steal warps or some ****. not cool.


The red was my baseline, no adjustments. Light blue was my final run and the settings i currently have. Im tempted to tweak them a bit using the run files alone. If i can lean out that 4k-4500 range, i can see a big power increase. That thing flies when at 13.5 AF





Edit: Dave, apologies if i cluttered your thread. If you want ill remove them and make a new one.

[MDeezy]

So the wideband that was used belongs to the shop? where was is located? before or after the cat?

SS headers are supposed last a while. not as long as the cast iron but still. I had SS ones on and they didnt warp. A Friend had the same ones on and its not warped..

you may want to set your activation point, and from there you can plot out your tuning points. You going to a dyno to tune? street tune?

all pulls were done in 3rd gear?

[shadyonedeath]

Wideband was in the exhaust tip. Yea...i thought it was weird too but it was a dyno day and i guess that was the quickest way of getting the WB in and out of cars.

Activation is set at 5100. I regret not using the power rod so i can see where it dies, but leaning out the car was more important to me at the time.

Yes, 3rd gear.

[Gemner]

that just means it was even richer than the graph reads. I noticed you made by far the most low end tq and hp with a 13.4:1 or so afr, probly should aim for that and taper it richer into the high revs whenever you get that wideband. Also, it looks like your VI activation oughta be around 5400-5500, but you will know that better by properly dyno testing it.

you should have told us its a dynapack, IIRC they read higher than dynojets, so youre likely making even less on a DJ than that 140whp you quoted. something more than afr seems off

[DAVE Sz]

shady, not my thread, but you're fine.
I was gonna say lower your activation point to 4900-0r 5000 but maybe deezy is right.
Your tuned numbers are what your baseline should be. Maybe the KS is screwed as deezy said. Still got nice gains from tuning.

[MDeezy]

Dave I was chatting with him and he has no codes no KS code, no o2 codes so I guess its just the DEK injectors spitting all that fuel out.

I think a dyno will be good for VIAS activation point. Do one run with no activation, then do another run with it stuck open. Examine both graphs and find the point where power falls off (no vias) and where power finally picks up (vias open)

I need to do this also. I have mine set at 3800 like a stock 3.5

[DAVE Sz]

the KS could be dying. The power loss might be intermittent. But it being bad on all 5 runs with no codes is unlikely. It might be the injectors, is your gas mileage crap Shady?
I know my car has developed a flat spot in 1st gear between like 1300-1800rpm. It just feels sluggish. My gas mileage seems fine though for car that swallows oil, has larger injectors, and isn't tuned. Ill hook up the OBD scanner and check how the timing is looking. Now where is that thread that showed timing differences between a good and bad KS...
nevermind, found it:
Ignition Timing Advance vs Knock Sensor Operation