God Forgives I Dont

I got my LTFT close to perfect then I hooked the MAF back up and now there a tad on the positive side. Should I tweak the VE table again or scale the MAF table? If you think I need to scale the MAF table, then could you explain how you would do that? I've been doing some reading but I don't think I 100% understand exactly what I should do and sense I'm so close to were I want I just don't want to make it way screwed up. Any help would be awesome! Thanks

Another_User

Tweak the MAF table. Either try a Holden table, or scale it by a few percent. There is no reason to tweak your VE table to try and bring your trims negative because your MAF table is what is off.

gojo

iTrader: (12)

Your trims are max +3. Multiply the entire MAF table by 103%. It should get your trims to be 0 to -5, versus where they are now, -2 to +3.

How's the car transition to idle?

Turo

iTrader: (23)

is your maf still stock (screen and everything)? my LTFT's were off way more than that when i plugged my maf back in, but mine is descreened. just wondering...

Tiger2o69

iTrader: (16)

before you scale the maf you might want to look at the post about how it throws everything off...

God Forgives I Dont

Stock MAF with screen from a 2000 car and I did a home port and polish on my throttle body.

Tiger2069 What post are you refering too about MAF scaling throwing off everything.

I can't deal with the SD tune, I personally think it sucks expecially when it comes to trying to tune any sort of stable Idle.

And as far as my current Idle transitions, it seems good to me. Well at least it isn't trying to die or surge with my MAF connected. Now with it disconnected It wouldn't Idle worth a sh*t and when I tried to make changes to make it better it only made it way worse and I ended up with major surging at idle and at low RPM coast. Just plain got sick of it, I was going to continue tuning the LTFT a little closer but the Idle just ticked me off and when I hooked up my MAF and saw how close it was I figured better leave the LTFT there and tune the MAF in to bring the LTFT back under zero.

Thanks for all the input and I'll be doing some more searching before I go into scale the MAF to see whats up.

Bink

Listen to gojo as he knows his stuff - especially about idle tuning through a MAF.

If you have some persistent surging you may want to talk to gojo about your
ported TB - just a thought.

There are many theories. Some are practiced routinely.

God Forgives I Dont

Yes you’re right! I've read many of GoJo posts helping out others. I'm going to go ahead and multiply the table by 103% and see what comes back.

No surging issues with MAF connected only while I had it disconnected for LTFT tuning!

Gojo my Idle seems good with the MAF connected. However sometimes when she is hot like if I just stop to run in a store for smokes and come back the Idle seems either lower or maybe not so much lower as it is erratic and can sometimes die. Do you ever use this Stall Saver feature? If so could you give me some pointers on how to configure it?

Also if you have a spare minute I have a shift point issue that is kicking my butt and I haven't had any luck searching with the description of the issue and would like to run it by you for your opinion.

Thanks for the help!

Billiumss

iTrader: (11)

If you have a stock MAF with screen, don't change the MAF table!!!

It is a calibrated device, adding a cam doesn't change the cal of the MAF sensor.

Why is everyone thinking this?

Another_User

He has a lid. That is all.

Tiger2o69

iTrader: (16)

https://ls1tech.com/forums/pcm-diagnostics-tuning/279035-scaling-maf-affect-pe.html

Personally dont know a lot myself except when I scaled mine it messed it up... It worked perfect for the current tempeture i scaled it at but when it gets warmer I get really rich...

God Forgives I Dont

That is a good point you make but you can't say that anything that comes off an assembly line is always dead on accurate because of the manufacturing tolerences. But again you do have a good point about the stock MAF. I wonder if there is a defference between the 99 and 2000 MAF? I had ported my 99 MAF and later bought a stock 2000 MAF as a replacement because I was having wierd issues. That issue actually turned out to be the MAP connection was just barly conecting and had nothing to do with the MAF.

Bink

If your VE table is sound and confirmed as such, MAFLESS, then the next step is to correct what you have added to the Mix.
VE table is Air and IFR is Fuel - both of which have confirmed as accurate.
So the next step is to correct the MAF - not by changing the curve but by scaling by a percent.
Remember, it (MAF) was calibrated before any mods to the intake tract. All that has been changed is total airflow through the meter - so rescale by a percent.

gojo

iTrader: (12)

The reason I asked about idle is that your trims down low are a little negative relative to the rest. Sometimes that indicates that idle airflow needs a little adjusting. The condition you describe is not unusual, I think because not enough emphasis is put on the IAPARK table. What's happening is that the car sits while you shop and IAT goes up. The car stumbles, surges or dies until, by driving, IAT drops down. Duplicate the situation while logging, IAT, MAF g/s and or DESAIR and IACDES. For each IAT level you need to match IACDES to MAF g/s by lowering or raising IAPARK. Set them up in your logger in a row and jot down the values you want to input. The values will never be perfect or match perfectly, so you will need to make small SOP adjustments. It will take time to get it right, because of outside weather. for example, mine are right for Fall, Winter and Spring, I expect they are not for hot Summer temps. Your description indicates you're close to SOP adjustments, now.
You should see your trims get a little closer, but they are pretty good as they are.
Do the MAF and let the computer do it's job. If your PE and IFR are calculated correctly and VE's are right, what's left but the MAF. When it's all running right, PE should be checked.
Have you done anything with spark? Your cam may need a little more timing down low. Especially Base spark drive and park. If your scanner has BI-D you can add a little at a time and feel the difference.

Shift point? Put it up. There are lots of guys that can help.

God Forgives I Dont

Once we hook up the MAF and it throws the LTFT off how do we correct it if we shouldn't scale the MAF? I don't want to fight with a SD tune it seems to me that it is totally enviromently calibrated and would need to be constantly adjusted with changes in the weather and in Texas that is almost a daily event! Not to mention Idle tuning doesn't seem work with any of the varios methods of tuning I have found online.

I don't care what anyone says this tuning stuff is complex to say the least!

I guess it does give me stuff to do and learn though!

Another_User

Your VE table is not accurate from the factory. I am pretty sure it is designed for it to run you fairly rich if you fall back on it completely. You MAF table is as close as it gets from the factory, but as soon as you change anything in your intake, particularly the lid, it is not accurate at all. All you have to do is look through a stock lid, and look through an aftermarket lid, and you will see how on the stock lid all the airflow at low speeds is aimed right at the sensors, an aftermarket is not, and allows unmetered air past, hence the screwed up MAF table.

Tiger2o69

iTrader: (16)

In Mississippi I am in the same situation you are. In the morning it could be 30 and then 80 by mid day....

Im confused as well lol.... Its frustrating at the least..

God Forgives I Dont

That sounds like a legitimate point. And in my specific case it can't be too far off. My LTFT weren't exactly dead on 0 (that only exists for a moment in time anyway), so my LTFT being only off by +3 isn't very bad at all IMOP. I guess given all of this new information you guys have brought up I'm thinking do what Gojo suggested and see what the results are. And of course I will not know about the PE results with out a wide band, but I'm about ready for that stage in the tuning process anyway.

Oops, no I forgot a step so who can explain what I need to do with the Timing. I haven't read up on that yet; I've been learning in steps as I go through the process.

One other thing has anyone exported there scans to Excel and sorted the data by Fuel Cell? If so what kind of results do you see on Cell 0? The scan I took that LTFT pic of has -100 and +100 for all the Fuel Cell = 0 (granted it’s only like 4).

Oh and let me thank all of you for putting in your thoughts on this! I definitely appreciate everyone’s 2 cents!

Another_User

If you touch your timing during cruise, non-WOT, with that cam, you can expect to make some more VE table changes.

God Forgives I Dont

HHHhhhmmmm.... Meaning? Just leave it alone then?


What steps do ya'll guys do for your own tuning?

This is/was my plan of attake for tuning my TA is this not a correct process?

1 Remove TQ Managment & adjust Shift points & Rev limiter
2 Emmisions Codes
3 Idle tuning
4 adjust LTFTs using SD tuning
5 MAF scaling
6 Timing adjustments
7 WOT tuning
8 Go back and do it all over again when the wether changes to extremes either colder or way hotter.