tuning issue afrs sweeping

[cadet18]

i have recently been trying to get my car back on the road and having been setting the tune with nistune. i have my idle set great and it will idle all day at 14.4 where i set it. now i am having the ecu target 11:1 at WOT on the fuel map with a smooth transition all the way up. problem is when i get into a cruise situation the car will sweep from 10:1 to 14.7ish:1 staying at the rich side way longer. it will get leaner if i give it a bit of gas maybe up to the low 12's. also when i go WOT it will go down to 11:1 then go up to 13.7:1 at WOT!!! i let off there i didnt want it to get any higher that was bad enough. no matter how much correction i make i cant get the ECU to compensate for these 2 problems. maybe my VQ map is set up wrong, or maybe my o2 sensor is causing this? i have 4000 mile rebuilt motor stock rods forged pistons tomei mls headgasket, FMIC, tubular bottom mount mani, 2860rs .64ar, 800cc deatschwerks, nismo fpr set to stock pressure, isis blast pipes, and nistune with the tuner license. maybe you gusy have some insight on this?!?!?!? i am new to tuning and my buddy who is very competent on rom raider with subies is helping me. any constructive thoughts?

[cadet18]

its also a z32 maf

[float_6969]

it sounds like you're simply in closed loop. Is there a way to change the parameters that activate closed loop?

[cadet18]

i believe nistune has a temp activation limit simply saying that when temp sensor sees "X" temp it goes into open loop im not 100% im still learning but i will def look into that!

[float_6969]

When I'm tuning, I like to "disable" closed loop for all of my tuning. I will tune the base map for part throttle so that the AFR's are pretty close to stoichiometric. Then when you activate the closed loop, the ECU has very little correction to supply. This makes it tends to swing back and forth MUCH less from my experience tuning an SDS. The Nistune may be different.

[cadet18]

so if i were to turn the temp feedback up all the way so it never reaches open loop would this be the same thing pretty much?

[Buddyworm]

I have a feeling your K and Injector latency need some tweaking. What do you have them set at? If those are set correctly you SHOULD see your AFR's follow your maps very closely. Latency is important at lower loads because the opening and closing of the injector takes up more of the total pulsewidth. I've found it also affects throttle response and low-end torque. K is impotant in all loads but dominates your fueling at higher load.

Nistune's injector and MAF conversion formulas will get your K pretty darn close to where it needs to be. So fine tune your idle mixture (in open loop) with latency and then go for a drive, put the engine under a bit of load and tweak your K for stoich at part throttle driving (may also want to ensure you're in open loop for this) then go park and tweak your latency some more to bring the idle back to stoich. Wash rinse and repeat until you're happy with the AFRs under all load conditions. It should take less adjustment to bring things back to stoich each time you repeat these steps.

Keep in mind the ECU will fatten up the mixture depending on how quickly you open the throttle so that might explain the initial rich condition when you start loading up the engine.

[cadet18]

so i went to go mess with it this afternoon and drove it around for a bit and it ran great still had the cruise issue but other than that it was awesome. i sat at my buddys house right up the street for a sec and when i left i got on it a little harder than normal but not over half throttle i heard a clunking around sound and then it started running rich and stumbling badly. i got it back to the house and found a timing cover bolt came out. i looked around and could see nothing else disturbed but it still ran like crap. i connected nistune and it said temp sensor. so i changed the temp sensor. with the new sensor in it still had a hard code for it so i messed with it some more now magically the code cleared but the car wont even start at all with no code. it is saying the temp is -30 or -40 i cant remember which but im in south ga and its at least 85-90 out. Any ideas?

[boost_boy]

NO signal to your ecu from your temperature sensor. Check your harness connectors for a poor connection.

[float_6969]

Yea, that's either a wiring problem with the sensor, or the sensor itself has failed.

[cadet18]

shot wires and it came down to bad wiring so i replaced wiring. car will start and idle now but its running SUPER rich. like not driveable rich. no boost leaks from what i can see until i get my tester back. like i said it idles smoothly but wayyyyy too rich
idk what else could have happened. this was a very sporadic event. it was 100% fine then after one semi hard takeoff everything went to crap instantly.

[boost_boy]

What is the reading of the water temperature sensor? If that sensor's reading is out of spec, the engine will run rich and/or be hard to start.

[cadet18]

water temp reading was 40c which was about right for outside. i notice when you first start it up it will run properly at 14.7 for about 5 secs then it will gradually go down to 10

[cadet18]

tried unplugging the o2 sensor... no change, did a leak test and found a coupler a little loose that didnt fix it. i ordered a new o2 sensor it should be coming in soon. the only code its ever thrown was the temp sensor.

[cadet18]

checked fuel pressure and cleaned the MAF no change and fuel pressure was normal. checked tps voltage and was within limits swapped CAS and no change. also checked belt timing the intake was a tooth off i fixed that with no change. i also swapped dropping resistor and ignitor with no success.

[cadet18]

Any ideas im considering buying a wiring specialties harness i dont want to buy a harness that doesnt fix the problem?

[float_6969]

It seems like you've checked everything. The harness is a possible culprit.

[cadet18]

could base timing cause this issue? i saw that the crank pulley was lined up(looking at the diff timing marks on the pulley and the pointer from the lower belt cover, not actually looking at the cog behind the cover) and only pulled the top cam cover to check timing? maybe i overlooked something? also do you think i computer would cause an issue like this? esp for it to happen out of nowhere like it did? i would think i would see fluctuation on my vacuum gauge if i had a bad valve.

[float_6969]

Definitely pull the crank pulley and lower timing cover and check the cam belt.

This is an odd problem, so it's hard to say what's causing it.

[louiswun]

I think you need to tune it all over again since you have fixed the water temp sensor and its wiring problem.
When you crank start your engine, the first few second did not control by the K value,
it's control by "crank start" table, and it is independently process the crank start fueling, after few seconds you release your key from start posistion (no power to starter), then the K value will take up the fueling task.

[cadet18]

Louis.... i have found that if i lower my latency from 980ms to around 380 ms i can bring my k constant to 187ish on nistune the previous running tune that was working on the car was a k value of 200 if i correct latency and k constant to idle at 14.7ish at idle it will still go rich under load. i am using nistune btw. As i said im still pretty new to this but i know my fuel map should be targeting 14.7 at cruise and appropriately for other load levels. Maybe i did something wrong and you have some insight to this. thanks for the help guys! im kinda stuck on this one usually i have at least a feint idea of wht direction to head in with engine problems but this one has me pretty stumped.

[cadet18]

went out and pulled timing cover today. intake cam is less than half a tooth off everything looks fine. i was really hoping that would be it. would jumping 1tooth be enough to bend a valve?

[louiswun]

I hope you understand my english.
Make sure you don't have any hardware problem, no DTC code show up.
There are few items you need to check before tuning, when engine is idling.
Press F6 to show up "Consult Gauges"
ECU voltage must be steady and should be around 13v while idle, while A/C off and head light off.
TPS Idle indicator should be in red light on when throttle off.
TPS voltage 0.45 - 0.50 V when throttle off.
check ECU parts number showing in nistune software, same as your actual ECU.
check VQ map is same as your Air Flow Meter.
For JDM ECU (or any other ECU that have O2 sensor) , unplug your O2 sensor, you should see around 0.32 to 0.34V default voltage, if not ( I see 0v showing in some problem ECU), check wiring between 02 sensor and ECU, if still not found any problem, try to remove the O2 signal female pin on the blue ECU connector on engine harness side, if you still don't see 0.32 to 0.34V default voltage, change ECU.
CA18 with z32 maf, maf (AFM) idle voltage should not lower than 1.040V, if you see any lower voltage, change to a better condition maf or you wll have hard time on tuning.
If any item not ok, fix it before tuning.

If ok, warm up your engine until you see 80 degree water temperature, any lower water temperature will let the water temperature enrichment enriched your AFR.
( If your are using JDM engine, a 82 degree thermostat should be inside your engine, if you have removed it, you will be difficult to target the K value)
start tuning your K value at vacuum stage, ignore the idle AFR at this stage, just enter your injector latency from deatschwerks supplied, hold your throttle as staedy as you can, hold at 2,500 rpm no engine load free rev, adjust your K value until you see 14.7 AFR, let off the throttle fully fast, while engine reving down, watch your AFR gauge, if you see your AFR have a rich spike then goes to max lean and then back to idle, thats mean your latency setting is too hi. (or your BOV spring too soft, fake AFM signal created)
If you have a too low latency, you will have instant max lean, and idle on lean side)
At this stage, a correct latency + correct K value, a too hi latency + too low K value, or a too low latency + too hi K value, all cases will have same 14.7 idle AFR.
0 all TTP min and 255 all TTP max.
Set your idle TP in the lowest Fuel/Ignition load scale, mine is 11 with 550cc injectors, yours should be lower with 800cc injectors.
set your fuel map left hand side (vacuum and low load side) to all 0 (Raw value).
open "input tracer" window , it is something like runing log, it helps tuning a lot.
start crusing on long flat road, 2nd or 3rd gear both ok, try to use your throttle to hold your pressure in 0 vacuum / 0 boost ( 0 psi), watch your boost gauge with one eye, watch your road with the other eye, while engine rev up, keep it in 0 psi steady while rev climbing, 2,000rpm to 5,000 rpm is ok, AFR should be close to 14.7, if not, adjust K value and repeat until you see 14.7, also check your max TP at 4,000 rpm in input tracer, let say if max TP is 32 (550cc + Z32 MAF usually see 32, 800cc + Z32 MAF should be lower) now you can determine how many column in your fuel/ ignition maps are for vacuum, let say you only need 6 column for vacuum and 10 column for boost, input 32 into the 6th column in your load scale, then line up the 1st to 6th column in the 2D map.
Select your fuel map display in "estimated AFR", set your AFR to all 12 AFR on the right hand side of the map, set your accuator or boost controller to the lowest boost, set your timing map right hand side to lower value ( 5 degree is ok unless you have horriable AFR). start full throttle in lowest boost, I usually start at 0.5 bar, adjust K value to reach 12 AFR, let throttle off if anything worng, repeat until you see whole rev range 12 AFR (just like your fuel map), fine tune your K value + latency combination, try different combination to see which works the best.
If you have a almost perfect K value, set your fuel map right hand side to 0.5 AFR richer than your target AFR, also lower some more timing on the fuel right hand side, set your boost controller to max target boost, do it in 3rd gear, let say you want 11 AFR at 20 psi, bring up the boost to 20 psi at this stage, set 10.5 AFR on your fuel map, watch your AFR gauge on accelerating, while it hit 20 psi and your AFR didn't reach 11 AFR, either your K value is too low, or your fuel pump cannot supply enought for your flow, if AFR at 20 psi is richer than 10.5, that is a good sign, your fuel supplying is up to the task, lower your K value until you see 10.5 AFR, once your have reach this point, do not change your K value and latency here after, check TP reading in "input tracer", if your max TP is 90, input 90 in the 15th column of your load scale, let 16th column be the overboost protection.
fine tune your fuel map to 11 AFR at 20 psi and any point in between 7 to 20 psi, and also fine tune your ignition map.
For a correct TTP min map, take the stock TTP min as a base map, in all 16 column, stock value x 370cc/800cc, then you will have a good TTP min map, leave the TTP max at all 255.
Sometimes you need to tune the TTP min at low end rev, apply light brake to force engine rev lower than idle rev 800 rpm, this will force your AFM signal lower than 1.040V, use the TTP min map to supply enought fuel to avoid engine stall at low rev.
A on-dash fuel pressure gauge will tell if your fuel pump can supply enought fuel.
If you do not have one, end up you will mess up your K value, will trying to use a higher than perfect K value to reach your target AFR, and make your low end richer than your target.
A re-circulate BOV will show the real AFR while throttle off just after boost, but most owner love the BOV sound, it will make latency harder to spot on.
If tuning step by step boost up ....5psi, 10psi, 15psi, 20psi, 25psi...end up you will found that your load scale not match with the hi boost, you need to scale it all over again, and mess up the tune done good on low boost.
There are many trick to get the tune perfect, like tuning the VQ map, but it will be too difficult for a new tuner.
Hope my $0.02 make you feel easier to tune with.
Wish you good luck.

[cadet18]

Thanks so much for that write up! i have never seen such a good write up for how to use nistune. i have the timing cover all torn apart right now but i will try and get it all put back together tomm morning and try this out. Thanks again for that awesome write up i wouldnt have expected that much help from anyone i know from most of the forums. i think i am going to order a new engine harness as well. another thing i forgot to add was that my fuel pump fuse has blown twice for no reason. i dont think it goes into the engine wiring from what ive seen so far so i dont see where the two could short on each other but who knows ill need to research.

[float_6969]

Blown fuses are nothing to mess around with. You either have a bad pump (they don't usually blow fuses when the fail, but it's possible) or you have a wiring problem.

[boost_boy]

Sort the electrical issue before you start dumping coins into parts you may not need. Like float says, the fuel pump fuse blowing is telling you something in itself. Take your time and go through your electrical system as well as checking your fuel pump's performance.

[cadet18]

ok found some touching wires by the fuse box and fixed those that should be the fuel pump problem. i started it up after redoing the timing belt again and the o2 signal stayed on 0 no matter what with the o2 unplugged. i am putting my nistune board into the ca18de ecu as we speak and hopefully that will fix this. why is it bad if your ecu sees 0 volts from o2 when unplugged?

[cadet18]

scratch the de ecu im going to get a new det ecu(new to me) and get the nistune switched over. also am going with a new harness just bc mine is a POS the connectors are all messed up and green. the ECU reads 0 volts all the time o2 plugged in o2 unplugged and sensor to the 128 pin connector wire completely removed from the harness saying the ecu reads full lean under all conditions. im pretty sure the ecu has somehow messed itself up.

[float_6969]

Yea, that sounds like a mess

[cadet18]

Thanks again for all the help guys. Especially louiswun i never would have checked that without your input. this is why i always go to nicoclub to get advice on things. you guys in the CA community help each other out here instead of just trolling the forums to try and be cool. hopefully one day ill know enough to help solve someone elses problem. Just wanted to say thanks guys! Ill keep you updated when i find an ecu and get everything installed.