Nistune Forums

So i read the entire nistune manual and i'm looking through the tuning guide but still i can't get it to run right.

car specs...
J30 Nissan Maxima
VG30ET motor
370CC injectors
stock MAF

with out touching anything the Wideband LC-1 is showing 32.
from the manual i'm reading it should be around 14ish.
i went into the k-constant and increased the number and the readings starts to change.

ok good...so i bring the AF reading to close to 14 and the car starts to stumble. it stumbles around low 15s and if i bring it to 14s the idle gets really choppy and almost wants to stall. idle is dipping below 850 and it gets real ugly.

so what to do here?

this is my first go at it and it doesn't seem like i can get step one right.

help?

also just to test i flipped on the AC and the car instantly stalled. i assume there's another program or parameter for the AC being on?

Before starting to tune, make sure the following things are ok:
- ignition base timing
- Camshaft timing
- No air leaks in intake system
- Fuelpressure

Then start out with a base map for your engine, perhaps with modified injectors or AFM (use nistune for this, and you might want to adjust injector latency manually). At this point your AFR's should be reasonable. If not, go back to the mechanics first, because something is still wrong!

Only after this you can try to tune around with injector multiplier, latency and map adjustments.


A poorly idling engine will stall when switching on AC, because of the extra mechanical load...


btw, where did you place the LC1? Anywhere near the tailpipe perhaps?

KillerB wrote:Before starting to tune, make sure the following things are ok:
- ignition base timing
- Camshaft timing
- No air leaks in intake system
- Fuelpressure

Then start out with a base map for your engine, perhaps with modified injectors or AFM (use nistune for this, and you might want to adjust injector latency manually). At this point your AFR's should be reasonable. If not, go back to the mechanics first, because something is still wrong!

Only after this you can try to tune around with injector multiplier, latency and map adjustments.


A poorly idling engine will stall when switching on AC, because of the extra mechanical load...


btw, where did you place the LC1? Anywhere near the tailpipe perhaps?

ignition timing is ok...i will triple check tonight. it also read the right timing on the consult gauges...is that correct place to verify?
camshaft and distributor timing is also ok...that frustrated me for some time but i finally got it right.
i used a smoke machine to check everything and everything seems to be ok...but i will try it again to verify everything is still sealed up.
fuel pressure is good (verified by gauge at the rail)...but i'm using the stock FPR.

should the MAF be the inlet side of the turbo or should it be before the TB after the turbo?

LC1 is not too far after the turbo in the down pipe.

DanNY wrote: LC1 is not too far after the turbo in the down pipe.

OK thats a good place, no chance of sucking in fresh air at the tailpipe.

DanNY wrote: should the MAF be the inlet side of the turbo or should it be before the TB after the turbo?

Im not familiar with this engine / maf, but normally a MAF is before the turbo, between airfilter and compressor inlet. Oh and make sure you dont place it too close to the compressor inlet, because that can cause lumpy idle also...

DanNY wrote: it also read the right timing on the consult gauges...is that correct place to verify?

Id measure it with a timing gun, then you know for sure.

DanNY wrote: i used a smoke machine to check everything and everything seems to be ok

I use a compressor for this purpose on my CA18. Just take the maf+airfilter off, place a beerbottle inside the rubber tubing to the compressor inlet, and hook up the compressor on the crankcase ventilation hose. Put some air in it, be amazed by how much the rubber hose starts to expand, and listen for leaks.

KillerB wrote:

DanNY wrote: LC1 is not too far after the turbo in the down pipe.

OK thats a good place, no chance of sucking in fresh air at the tailpipe.

yeah i tried to get as close as possible to the turbo (in the DP) w/o too close and over heating the WBO2

DanNY wrote: should the MAF be the inlet side of the turbo or should it be before the TB after the turbo?
Im not familiar with this engine / maf, but normally a MAF is before the turbo, between airfilter and compressor inlet. Oh and make sure you dont place it too close to the compressor inlet, because that can cause lumpy idle also...

it's not right next to it...there's a 90 degree turn and about 3-4 inches down.

DanNY wrote: it also read the right timing on the consult gauges...is that correct place to verify?
Id measure it with a timing gun, then you know for sure.

i used the timing gun to make sure and when i got it set i got back in the car and fired it up and nistune gave me the same number. i'm just confirming that the nistune timing number should be the same as the timing light/gun number.

DanNY wrote: i used a smoke machine to check everything and everything seems to be ok
I use a compressor for this purpose on my CA18. Just take the maf+airfilter off, place a beerbottle inside the rubber tubing to the compressor inlet, and hook up the compressor on the crankcase ventilation hose. Put some air in it, be amazed by how much the rubber hose starts to expand, and listen for leaks.

hmmm so add air into the intake from the PVC valve and plug the filter inlet w/ a beer bottle? that's a good idea...i'll give that a go. how much air/pressure should i attempt to pump in there (PSI)?

thanks for your help so far.
Dan

Im not sure the 3-4 inches is enough. I think for Z32 maf it could cause problems, but i cant say for your maf. Perhaps someone else can help u with this...

As long as the timing gun shows the same number as consult, base ignition timing is OK

Oh and just put like 0.5bar (7-8psi) in it and you should clearly hear a hissing sound when you have a leak. I dont use the PCV valve hose for it. On ca18 there is an additional ventilation hose between the camshaft cover and the the rubber hose between maf and turbo. I disconnect this hose at the camshaft cover and attach the aircompressor here. This has 2 functions:
1. You get the air in the intake system (duh...)
2. No pressure is fed into the crankcase which might damage oil seals

But as long as your solution does the same thing, i say go for it

KillerB has pretty much nailed it but I'd just like to add that usually you'll find that engines will idle nicely anywhere from around 12:1 to about 16:1. This varies from engine to engine but that's a representitive range.

Richer than 12:1 and they'll start to get fluffy, you'll smell the richness from the tailpipe and idle speed will decrease. Engine will usually still free rev OK. Plugs will start to foul if left to idle richer than 12:1.

Leaner than 16:1 and they'll start getting lumpy - often as if you've got a bit of cam going on, and once again idle speed will decrease. Any attempt to rev the engine usually results in a lean stumble and they'll often stall. I had an RB26 idling at 22:1 awhile ago but it was quite lumpy at that AFR. Most SR20's seem to get unhappy around 17:1.

It just seems weird that yours is upset at 14 - 15:1. That's usually the sweet spot for idle. I'm kinda suspecting an erroneous reading from the wideband.

PL

My LC1 doesn't go past 21.9 on the lean side so i don't know how you got 32 initially ? Maybe remove and recalibrate the sensor in free air?

PL wrote:KillerB has pretty much nailed it but I'd just like to add that usually you'll find that engines will idle nicely anywhere from around 12:1 to about 16:1. This varies from engine to engine but that's a representitive range.

Richer than 12:1 and they'll start to get fluffy, you'll smell the richness from the tailpipe and idle speed will decrease. Engine will usually still free rev OK. Plugs will start to foul if left to idle richer than 12:1.

Leaner than 16:1 and they'll start getting lumpy - often as if you've got a bit of cam going on, and once again idle speed will decrease. Any attempt to rev the engine usually results in a lean stumble and they'll often stall. I had an RB26 idling at 22:1 awhile ago but it was quite lumpy at that AFR. Most SR20's seem to get unhappy around 17:1.

It just seems weird that yours is upset at 14 - 15:1. That's usually the sweet spot for idle. I'm kinda suspecting an erroneous reading from the wideband.

PL

it idles ok once it hits like high 15's...really weird.
i'll do a recalibration again on the wideband to make sure it's ok.

once this crazy 100 degree temp break i'll go out there and check it out.

CoZZm0 wrote:My LC1 doesn't go past 21.9 on the lean side so i don't know how you got 32 initially ? Maybe remove and recalibrate the sensor in free air?

i think it's pegged at 32...it doesn't go any more over than that. i'll try the recalibrate again.

KillerB wrote:Im not sure the 3-4 inches is enough. I think for Z32 maf it could cause problems, but i cant say for your maf. Perhaps someone else can help u with this...

As long as the timing gun shows the same number as consult, base ignition timing is OK

Oh and just put like 0.5bar (7-8psi) in it and you should clearly hear a hissing sound when you have a leak. I dont use the PCV valve hose for it. On ca18 there is an additional ventilation hose between the camshaft cover and the the rubber hose between maf and turbo. I disconnect this hose at the camshaft cover and attach the aircompressor here. This has 2 functions:
1. You get the air in the intake system (duh...)
2. No pressure is fed into the crankcase which might damage oil seals

But as long as your solution does the same thing, i say go for it

figure the 90 degree in the intake will figuratively add to the length of the pipe.

i'll put a little air in the intake manifold and see what i get.
thanks for your help!

finally got it to idle right....
so it turns out there was a little leak in the exhaust manifold a little before the WB so that cause the super lean situation or the lean display from the LC1.

got that all fixed up and got the car running around 15ish and it idles perfectly fine. the problem is when i hit the gas pedal to rev it instantly stalls.

now here's the funny part...i after stalling a few times and having issues restarting the engine and etc all of the sudden the car will start up and bam it runs like a dream. AF is good, idle is good, throttle response is good. what is going on? it is going to a knock map? if that's the case that seems to be fine for right now.

after toying with the injector multiplier the car's AF doesn't really change (this is when it was running perfect). then after running it a little bit it goes back to the symptoms as before.

i'm trying to follow through w/ the guide and it's a little confusing on how things should run b/c the engine seems to stall right away when i'm making changes or if i press the throttle.