Adjust latency around idle, k value from 3k+. As long as the car starts and drives fine, I would make minimal changes to get the afrs where desired.Whacker wrote:I adjusted the k value 'til it was about right on idle but perhaps it's better to have a closer target AFR on high loads and then just change it on low load area until it seems fine?Bernardd wrote:If the actual afr's on the higher load area of the fuel map are richer than the commanded afr's the k value is too large.
XR Pilot wrote:Whacker wrote:[I'm using modded standard injectors so the latency shouldn't be any problem.. I don't think there are any problem with the injectors either but of course I can't be sure..
Playing around with latency might help.
Very unstable idle and AFR
Moderator: Matt
Hmm, could try adjusting it a little.. But my k value is set at 21k something..Bernardd wrote:
Adjust latency around idle, k value from 3k+. As long as the car starts and drives fine, I would make minimal changes to get the afrs where desired.
Is that too high?? Or are we talking about different values?
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skyline_stu
- Posts: 151
- Joined: Tue May 13, 2008 10:48 am
- Location: Wide Bay Queensland
Yes I know the importance of it but that's why I'm afraid of that it might be that.. But I'm not really able to get a new set so I have to get this running or let the car be in the garage for all summer..skyline_stu wrote:"MODDED STANDARD INJECTORS" <-- There's your problem, as said earlier. Seen this SO many times before, spray pattern is more important than most people think
And we have like 4 good months here to drive in and 1 has passed already.. Besides I have a cap on the injectors giving a better spraypattern...
However, I recalibrated the wideband and it's a little more stable now...
The next problem I have is the width of the values in the fuel table...
I'm trying to run Auto Tune..
At first I adjusted the k-value 'til AFR show 14,7 on idle and the filtered value is 0..
But then as I'm trying to drive the auto Tune very soon had to adjust the cells to beyond -63 value.. So the fuel in the fuel map are less at the high load area for the AFR to be right..
Then I adjusted the k-value to be correct at 60 filtered value at 14,7 on idle.. But I still reached -63 value before going into high load area...
It seem like there's some big "Enrichment" problem.. but I've lowered most of them al ready.. the only one I don't really know how to adjust is the "Injection Response" and the "Increase Fuel" tables...
Honestly I'm not really sure about the Trottle Open Offset Either
Anyone with any ideas at all of what might be causing this?? =/
If you've got a large exhaust pipe on the car it may be throwing off your AFR readings at idle.
Try turning off O2 feedback, zero out the entire fuel map Then go for a very light load cruise around the block. During this run don't use auto tune, adjust the K value until you get 14.5-14.7:1 at around 3000rpm or so on a light cruise. Stop the car, see if it will idle. Adjust the injector latency by ear to get a smooth idle (you should find that the value is 200-300 higher than stock from memory for best idle). Once the car is idling as best you can, restore the fuel map. You may need to fiddle with the fuel map around idle if it uses strange values. Now go for a drive with someone keeping an eye on the AFR's. I'd probably recommend getting a passenger to check it instead of auto tune. You'll probably find you need to take out heaps out of the fuel map up high as it will go 10:1s. You will probably need to take 20-30 out of the fuel map to get reasonable mixtures (again going by memory). If you can't get the AFR's reasonable at full load you may need to adjust the K constant again.
Give that process a shot, no guarantees but it may work for you. You may need a little more load on the motor when setting the initial K constant, maybe up to 5" of vacuum or so.
EDIT: Just watched your video again, I've got to say that spray pattern is pretty poor. Have you tried pulsing the injector at very low pulse widths at low RPM? You will more than likely find the injector dribbles instead of giving you a nice atomised spray.
Try turning off O2 feedback, zero out the entire fuel map Then go for a very light load cruise around the block. During this run don't use auto tune, adjust the K value until you get 14.5-14.7:1 at around 3000rpm or so on a light cruise. Stop the car, see if it will idle. Adjust the injector latency by ear to get a smooth idle (you should find that the value is 200-300 higher than stock from memory for best idle). Once the car is idling as best you can, restore the fuel map. You may need to fiddle with the fuel map around idle if it uses strange values. Now go for a drive with someone keeping an eye on the AFR's. I'd probably recommend getting a passenger to check it instead of auto tune. You'll probably find you need to take out heaps out of the fuel map up high as it will go 10:1s. You will probably need to take 20-30 out of the fuel map to get reasonable mixtures (again going by memory). If you can't get the AFR's reasonable at full load you may need to adjust the K constant again.
Give that process a shot, no guarantees but it may work for you. You may need a little more load on the motor when setting the initial K constant, maybe up to 5" of vacuum or so.
EDIT: Just watched your video again, I've got to say that spray pattern is pretty poor. Have you tried pulsing the injector at very low pulse widths at low RPM? You will more than likely find the injector dribbles instead of giving you a nice atomised spray.
Spray pattern looks interesting. It looks similar to RX7 spray pattern -
http://www.youtube.com/watch?v=yLbY5ZBo_FA
I gather it needs to spray like this on piston engine -
http://www.youtube.com/watch?v=3D-RJ0iv ... re=related
From what I understand with throttle enrich (more fuel on top of what ECU already injects), ECU looks at TPS voltage due to butterfly inside throttlebody (or butterfly's inside throttlebody's if you have a RB26, SR20, etc) reacts faster and airflow will increase more rapidly than what ECU will inject which makes the engine suddenly go lean (known as transient response). If not enough fuel, engine can stumble before accelerating. Especially when there's a longer vacuum hose to MAP sensor which from what I understand makes the ECU take longer to react and inject more fuel to match incoming air.
If you have played with carberrators before, it's what the accelerator pump normally does. It adds a little bit of fuel to combat the sudden lean condition when carberrator opens. I gather increase fuel is similar to duration setting on accelerator pump and throttle enrich is the volume of fuel. Also I think these settings change when you add intake, exhaust, bigger diameter throttle body, etc as the response time of engine and amount of air entering engine changes.
Throttle open offset might be the increase fuel (duration) offset. If you look at the voltages (mv) on increase fuel adjustment window (window above table, where you make adjustments) and on throttle offset adjustment window, voltages are at different ends of window or offset to each other. It might be when the throttlebody closes, uses the throttle open offset table. But when throttle body opens, uses the increase fuel table.
Play with throttle enrichment with wideband after getting fuelmaps correct, as it can affect the A/F ratio.
http://www.youtube.com/watch?v=yLbY5ZBo_FA
I gather it needs to spray like this on piston engine -
http://www.youtube.com/watch?v=3D-RJ0iv ... re=related
From what I understand with throttle enrich (more fuel on top of what ECU already injects), ECU looks at TPS voltage due to butterfly inside throttlebody (or butterfly's inside throttlebody's if you have a RB26, SR20, etc) reacts faster and airflow will increase more rapidly than what ECU will inject which makes the engine suddenly go lean (known as transient response). If not enough fuel, engine can stumble before accelerating. Especially when there's a longer vacuum hose to MAP sensor which from what I understand makes the ECU take longer to react and inject more fuel to match incoming air.
If you have played with carberrators before, it's what the accelerator pump normally does. It adds a little bit of fuel to combat the sudden lean condition when carberrator opens. I gather increase fuel is similar to duration setting on accelerator pump and throttle enrich is the volume of fuel. Also I think these settings change when you add intake, exhaust, bigger diameter throttle body, etc as the response time of engine and amount of air entering engine changes.
Throttle open offset might be the increase fuel (duration) offset. If you look at the voltages (mv) on increase fuel adjustment window (window above table, where you make adjustments) and on throttle offset adjustment window, voltages are at different ends of window or offset to each other. It might be when the throttlebody closes, uses the throttle open offset table. But when throttle body opens, uses the increase fuel table.
Play with throttle enrichment with wideband after getting fuelmaps correct, as it can affect the A/F ratio.