WB Maf Tuning ... Questions/Logs

[Dirty Howie]

Update: couldn't wait till monday

Below are logs from today and updated tune.

Seems to suck right up to stoich when accelerating but very rich when low rpm/map

Ran in 2nd only, 3rd and 4th on freeway.

How's it looking???


DH

[MMGT1]

Open your histo and view your log in VE AFR Error%. Copy the AVERAGE result and Paste Special Miltiply by % to your VE table in editor. It is very rich. Looks like a good run in the cruise area's though. Then, as always, scan your results on another run and let's see where you went with it....



Your VE table should look like this when you add that scan

Attachment 4360

[5_Liter_Eater]

Looks way better than the first one. Keep at it. Lather rinse repeat. Don't be afraid to go into PE or past 4000. Even though the PCM should use the MAF solely above 4000 there are still throttle transitions and such where it may want to look back at the VE table. Just keep an eye on the actual AFR to make sure you're not too lean and/or knocking. Maybe create a dashboard that has two big dials/meters. KR and AFR so it is easily read. That way if the whole VE table is spot on you can run in SD if you find that it runs better that way.

[Dirty Howie]

Guys.....here is todays log and adjusted tune.

Seems like I have good AFR when I am lightly accelerating.

When decelerating I seem to go RICH......I don't understand why????

I will go PE more for those transitions......

I got one spot of KR under load/light accel/in 4th on the freeway......I dont think this is a worry do you??

Should I be switching to %-1/2 ?????

How's it looking??


DH

[Dirty Howie]

Well someone please teill me why I am getting KR. I used to never show ANY. Now this last log there were 3 or 4 and one was 4.7 KR

AND my PE timing used to be steady at 20.5
Now when I go PE the timing is bouncing around between 16.5-19. You can see this in frames 8750 and 11850

I thought things were going good and now I think they are not.

Maybe I need to drop the VE and tune the MAF

Somebody needs to give me some advise here


dH

[5_Liter_Eater]

IMO the KR you are seeing is nothing to worry about. I don't see anything more than 2.55 degrees of KR and if you look at the average KR it's still well less than one degree (If you add a few decinal points to the KR histogram). Not like you're consistently seeing KR in that range. You're not logging TPS/ETC position so I can't tell if that KR is happening while lugging the motor around in too low a gear or during a WOT run. It's only happening ~2400-2800. Consider taking a few degrees out of those ranges. Don't worry terribly about what your decel cells look like. I could never get those right and just ended up enabling DFCO after I got the tune right. Saves on gas.

[Dirty Howie]

OOPS......I forgot to log the last log from yesterday!!!


DH

[5_Liter_Eater]

How's it coming Howie?

[Dirty Howie]

How's it coming Howie?

Well I decided to start over today...... Not a big deal.

I wanted to make sure all my logs were with car warmed up and NOT hitting PE.

Some of you say hitting PE during VE tuning is ok. Other respected members say VE is a waste of time and to just do the MAF. So what is a dummy supposed to do??????????

Also I didn't reset the fuel trims last time with the VCM.......so now before each log I am turning off CL, FT learning and reseting FT's. Actually I just finished a post asking if these stay in affect while car is running so that I can log with just the MPVI not connected to the computer......

In a couple of days I will try the PE WOT in 2nd gear

Thanks for checking back!!!!!


DH

[5_Liter_Eater]

It's definitely OK to go into PE for VE tuning (when tuning with a wide band)but if you plan on re-enabling the MAF it is somewhat pointless to tune the VE above 4000. From 4000 on the PCM is using solely the MAF readings. I just like to have the VE totally dialed in. That way you can stay in SD (MAF disabled) if you so choose and in the event of a MAF failure you know you're VE cells are correct.

You are in open loop so fuel trims should not even come into play. Your tune should have closed loop disabled, long term fuel trims disabled and open loop short term fuel trims disabled and MAF disabled as well. All of this is in the OL & CL tab (save the MAF). You shouldn't NEED to turn off fuel trims in the VCM controls if you have done all this. Keep this all disabled until you're happy with you're VE, then re-enable the MAF and keep fuel trims and closed loop disabled. Once you're happy with MAF turn closed loop and fuel trims back on.

[Dirty Howie]

It's definitely OK to go into PE for VE tuning (when tuning with a wide band)but if you plan on re-enabling the MAF it is somewhat pointless to tune the VE above 4000. From 4000 on the PCM is using solely the MAF readings. I just like to have the VE totally dialed in. That way you can stay in SD (MAF disabled) if you so choose and in the event of a MAF failure you know you're VE cells are correct.

You are in open loop so fuel trims should not even come into play. Your tune should have closed loop disabled, long term fuel trims disabled and open loop short term fuel trims disabled and MAF disabled as well. All of this is in the OL & CL tab (save the MAF). You shouldn't NEED to turn off fuel trims in the VCM controls if you have done all this. Keep this all disabled until you're happy with you're VE, then re-enable the MAF and keep fuel trims and closed loop disabled. Once you're happy with MAF turn closed loop and fuel trims back on.

I'm pretty sure my tune is setup correctly with everything disabled (you could check please). I did not let car warmup last time around. And wasn't sure if resetting FT with VCM was necessary. Also my VE table looked very rough. So I just wanted to start again before doing the Maf.

Also do you know why in the editor it is simple to toggele the STFT off but not the LTFT. I like the VCM ......just toggle CL, FT off and reset.


DH

[Dirty Howie]

How come even though DFCO is disabled (I think) there is obvious very lean spikes when throttle position goes to zero.......


DH

[2000C-5]

What's it gonna take to get the term LTFT out of your vocabulary?

Your fuel trims will now only be used when you are completely done and back in closed loop, just to check your work.

I don't understand why someone would say that tuning the VE is a waste of time. If your fueling is say, 10% lean or, in other words, adding 10% fuel, it is my understanding that the fuel trims will add that same 10% fuel even if you are in PE mode. If you command 13.0 AFR and the fuel trim adds its 10%, your actual AFR is going to be 10% richer than 13.0.

How come even though DFCO is disabled (I think) there is obvious very lean spikes when throttle position goes to zero.......


DH

Mine is the same way. The lean spikes are less than a second long so, I guess that when you lift the throttle, the injectors react instantly and stop fueling, while air is still flowing from the back of the, now closed, throttle plate, down through the motor, causing it to read lean. You can look at mine and see the spikes every time I make a shift.

[Dirty Howie]

What's it gonna take to get the term LTFT out of your vocabulary?

Your fuel trims will now only be used when you are completely done and back in closed loop, just to check your work.

I don't understand why someone would say that tuning the VE is a waste of time. If your fueling is say, 10% lean or, in other words, adding 10% fuel, it is my understanding that the fuel trims will add that same 10% fuel even if you are in PE mode. If you command 13.0 AFR and the fuel trim adds its 10%, your actual AFR is going to be 10% richer than 13.0.



Mine is the same way. The lean spikes are less than a second long so, I guess that when you lift the throttle, the injectors react instantly and stop fueling, while air is still flowing from the back of the, now closed, throttle plate, down through the motor, causing it to read lean. You can look at mine and see the spikes every time I make a shift.

Hey ..... you just used "FT" more than me. I get it ..... no LTFT until going back to closed loop, right??

I don't see your log to compare to??

Here is my latest log and tune correction. The numbers in my VE table are getting significantly smaller in the higher RPM/MAP ranges. Doesn't this mean that my engine is flowing less air than origanally tuned for??? Should I also expect better MPG now???

What do you think?????


DH

[5_Liter_Eater]

Looking better although the higher RPM, higher load cells still need some work but I think thats because you haven't modified those as much yet. The lower VE numbers don't really mean anything. The numbers that were in there before were just too high, they clearly weren't tuned in, probably just increased arbitrarily. The higher the VE #'s are (while maintaining a reasonable % AFR Error) the more efficient/powerful your motor is. High VE #'s with high negative AFR error #'s just indicates a falsly inflated VE. You would see better mileage in open loop because you're giving the motor up to 15% too much fuel (3200 RPM, 90 kPa) at some point. In closed loop the fuel trims would account for this so no mileage gain or loss.

Zero knock I see. Thats good. Did you do anything with the spark?

[Dirty Howie]

Looking better although the higher RPM, higher load cells still need some work but I think thats because you haven't modified those as much yet. The lower VE numbers don't really mean anything. The numbers that were in there before were just too high, they clearly weren't tuned in, probably just increased arbitrarily. The higher the VE #'s are (while maintaining a reasonable % AFR Error) the more efficient/powerful your motor is. High VE #'s with high negative AFR error #'s just indicates a falsly inflated VE. You would see better mileage in open loop because you're giving the motor up to 15% too much fuel (3200 RPM, 90 kPa) at some point. In closed loop the fuel trims would account for this so no mileage gain or loss.

Zero knock I see. Thats good. Did you do anything with the spark?

The higher RPM, load cells were not hit too much (filtered at 25 counts) as I was trying not to go PE. I may go ahead and get on it to see where they are before I do the MAF tuning.

My car feels strong, so I am diappointed that the (presumed VE) is not being realized

You say I would see better milage in open loop...not understanding this??

No changes in timing tables. The weather cooled from 80's to 60's the last couple of days. Only KR that usually shows is when its hot and I am lugging in 4th around 2K rpm.

Thanks for staying with me!!!!


DH

[5_Liter_Eater]

so I am diappointed that the (presumed VE) is not being realized

What do you mean? Do you have any idea where those numbers came from? I'm sure they were fairly arbitrarily changed from whoever did your first tune. Now you're just being silly.

You say I would see better milage in open loop...not understanding this??

Because your afr errors are as much as -15% so you're putting in 15% too much fuel. When you go back to closed loop even if you were 15% fat in VE cells you didn't edit the fuel trims would eventually learn to take 15% out.

[S2H]

You say I would see better milage in open loop...not understanding this??

Because your afr errors are as much as -15% so you're putting in 15% too much fuel. When you go back to closed loop even if you were 15% fat in VE cells you didn't edit the fuel trims would eventually learn to take 15% out.

open and closed loop will get the same MPG if tuned properly...
it doesnt matter which mode you are in....0% error or 0 fuel trims is the same fueling...
if your trims are +15 and your AFR error is 15 off as well then its the same dam thing...either way you need to fix it and get the correct fueling in there...

you can get better mileage in closed loop as the car will cprrect for what it needs....most people do see better mileage in closed loop for this reason...
they dont tune the entire tune and when the temp changes and their fueling needs change they are wasting fuel...meaning most people tune for hot..and when winter comes aroudn they are wasting fuel as they dont need as much when its cold out due to the molecular mass of fuel changing with temperature(we still need the same fuel mass..but the injectors cant tell that its heavier...so its putting in more fuel)

then again you get a tune like my 2000 SS camaro had and its dead on in open and closed loop and I got almost exactly the same fuel mileage in either mode...within a couple of tenths of a mile per gallon on a long trip..closed loop there..open loop back home

most of the time your trims will behave similar to your wideband...
if you were lean on wideband fuel trims will show the same(+trims)
if you were rich then fuel trims will show that (-trims)

if you were way lean or way fat...it wont be the opposite....the narrowbands may not be very accurate once you start modding..but they dont go the opposite of a good wideband...they usually still reflect whats going on in general...

[Dirty Howie]

What do you mean? Do you have any idea where those numbers came from? I'm sure they were fairly arbitrarily changed from whoever did your first tune. Now you're just being silly. .

Actually I just went and looked at a couple of other 402 engine VE tables. In the areas of the table that I have tuned.....I am somewhere between the two comparison files.

Because your afr errors are as much as -15% so you're putting in 15% too much fuel. When you go back to closed loop even if you were 15% fat in VE cells you didn't edit the fuel trims would eventually learn to take 15% out
.

Ok.....I understand this.....THANKS!!!!!


DH

[Dirty Howie]

open and closed loop will get the same MPG if tuned properly...
it doesnt matter which mode you are in....0% error or 0 fuel trims is the same fueling...
if your trims are +15 and your AFR error is 15 off as well then its the same dam thing...either way you need to fix it and get the correct fueling in there...

OK!!

you can get better mileage in closed loop as the car will cprrect for what it needs....most people do see better mileage in closed loop for this reason...
they dont tune the entire tune and when the temp changes and their fueling needs change they are wasting fuel...meaning most people tune for hot..and when winter comes aroudn they are wasting fuel as they dont need as much when its cold out due to the molecular mass of fuel changing with temperature(we still need the same fuel mass..but the injectors cant tell that its heavier...so its putting in more fuel)

Trying to get my mind around this. I thought that since cold air is denser it requires more fuel for the proper mix. I know the injectors cant tell shit...they are stupid. But the PCM doesn't compensate here???

most of the time your trims will behave similar to your wideband...
if you were lean on wideband fuel trims will show the same(+trims)
if you were rich then fuel trims will show that (-trims)

if you were way lean or way fat...it wont be the opposite....the narrowbands may not be very accurate once you start modding..but they dont go the opposite of a good wideband...they usually still reflect whats going on in general...

I totally understand.....lean WB= +Trims and rich WB= -Trims (will look at this when go back to CL)

Not sure what you are saying in the last paragraph??? If the NB turns out to be not accurate I would think one would want to stay OL ????? I'm not loging NB now but will shortly.


DH