Hi guys, New tuner here with a few questions. I have a 1985 corvette that I repinned to the 165 ecm and am using the arap bin from a 1989 corvette with the 6e mask. I have an idle that is very close to 128 blm/int by adjusting the injector pulse width correction vs. battery voltage table and massaging MAF table 1. My cruise in town is very close to 128 on both blm/int however when I get into giving it a little more gas it acts like it needs to spool up before it accelerates further. I have several data logs that shows that the o2 sensor for those moments is down to under .100mv. Granted I log at 8192 baud so it is less than a second that I see this trend however I'm at a loss as to what tables then need to be adjusted. I've followed this board in the DIY Prom section for a long time and have read the stickies on tuning however there isn't alot of talk about the 6e mask. Is it the upper MAF tables that I now need to adjust to get rid of this lag? I only have a few knock counts on startup and few if any while WOT or cruising in town so I think that the apap timing tables are good for my combo however I did adjust the maximum spark advance table to 38 degrees. I also have my injector constant set at 24# for my FMS injectors and my AFPR is set at 43.5psi. According to this calculator: Joe Georger's Home Page I should be good to go as far as having the correcto parameters for fuel. I'm all ears for any suggestions. Thanks for your time. Chad oops I should mention that I'm using Tunerpro RT 4.14 and the APU1 to emulate

I am not an expect here, but anyway, I would never use the battery voltage table for idle or off idle tuning. Set that table back to where it was. Work with the MAF tables first. Get the BLMs in FTCs 0 thru 10 to be between 122 and 134. (Messing around to get exactly 128 is a waste of time.) When you are cruising around and doing your logging, you will most liking "see" FTCs 0(idle), 5, 6 and 10, most of the time,,, but this depends greatly on your cell boundaries.

Also, you need to check the fuel injector constant,,, I prefer to have it set correctly, but sometimes you need to adjust it a bit.

You will also have to work on cold starts and hot starts. The engine starts up in open loop, so you ned to address stuff there also.

But most importantly, work on one thing at a time.

Thanks for the reply! I have cold starts down with the adjustment of the crank fuel pw multi vs ref pulse table so I am good to go there and she starts right up. I have noticed on several posts that trying to achieve 128 across the board is pointless so I'm not shooting for perfection. Sorry I don't know what FTC's are? I will change the battery voltage table back to the way it was and work strictly with the MAF table at idle to get things good there. My only problem is that tip in or spool up to add more fuel. It's almost as if it was girgling as it does it when I have my foot into it or keep it steady at a certain RPM range its the same feeling until it gets past that point and then it finally kicks in. I have watched my TPS voltage with the key on and it moves through all of the voltages up to 4.22v which at the bottom of the floor I'd assume is full throttle. I have lots more playing to do but this is some interesting stuff to learn. Hopefully some more folks jump in too with some ideas. Thanks again!

I'm going to guess it's a combination of Acceleration Enrichment (AE), and maybe MAF table 1-2. Make BIG changes to AE to see if it gets better or worse. Like double the Ctemp multipliers (for both TPS AE and LV8 AE), or halve them. Once you find the right direction, fine tune it. Does the engine sound like it might be backfiring through the intake (popcorn under the hood), or does it sound like backfiring in the exhuast (popcorn under your seat). Intake backfire is Lean, so add more AE. Rich (which I doubt), take a guess what to do!

Also, just by looking at the parts, 24# injectors are a little small. Might work for you, but if I were going to spec injectors for that, I'd start at 30's.

I was hoping you'd pop in RednGold. You seem pretty knowledgeable on the 165 so I appreciate your help. I will work more on the AE tables and go from there. Unfortuneately the injectors are here to stay for now or until I feel I'm hitting the wall on the tune and the injectors are holding me back. I do have a question though. I have both Single Fire Mode and Double Fire Mode at 24# injector constant. I have my AFPR set at 43.5pds at the fuel rail. Is that ok or should I use some other number. I have used the calculator from here: Joe Georger's Home Page and according to that calculation I'm correct. Any insight to that would be great! Thanks for the reply!

Fuel pressure and injector constants sound correct as you have them. If you find you're running out of fuel at high RPMs, you can raise your fuel pressure and raise the injector constants accordingly (Although I'm not sure if $6E EVER uses single fire mode, even at low PWs). Just remember that higher pressure will reduce your fuel pumps total flow rate, so you can't go too far, unless you get a better pump (hope you have at least a Walbro 255).

Setting max spark advance to 38 isn't much use, not sure why you would do that. It typically won't have any effect except at light load.

With a modified engine, you should also raise the Max Airflow Vs RPM. Set the highest RPM values to 255 g/s, and follow some simple trend down at lower RPMs, like the stock table, only more though.

Also, with a modified MAF, you'll have to redo the MAF scalars when you redo the MAF tables. With tunerpro, you can have the MAF tables refer to the MAF scalars, so that if you change the Scalar, you'll see that the MAF Tables change, and then you can re-correct the tables to have a linear progression from one table to the next.

For AE and a large engine, with large intake, and small injectors, you may need to find a way to increase the AE PW. Not sure if JUST increasing the Max Async PW will do it, or if you also need to increase the %BPW factor vs Async PW. I'm skimming the code a little to see if it's obvious or not. I'll try to get back to you on this.

Hey that'd be great if you have more info. I do appreciate it. I will follow your advice and change the total spark advance back to what was set in the original ARAP bin as well. I like so many people followed the advice to gut the MAF thinking it was helping and it may very well have but now I have to deal with it in the tune. My bad.....I'm learning though. Do you have info on how to set the scalar tables and MAF tables to refer to each other? I'm lost on that part. Thanks again for your help!

Try this XDF. Still haven't taken the time to find out the other info yet. I think I'll have time today, but I'm terrible at remembering to do stuff.

So if I'm to understand this right according to the XDF you included I looked at the link between the MAF tables and the MAF scalars so that I can link them together and make the change in the MAF scalar table only and the MAF tables will adjust accordingly. I understand that at idle I'm to massage MAF table 1 to get 128 BLM/INT across the board as close as possilbe. Now the other tables I should just be able to adjust with the scalar slider now that they are both linked together after I make a change to MAF table 1-link it to MAF Scalar Table 1 and then the others should fall in place accordingly? I think this is what you mean but if you could clarify that would be great. You have been a huge help! Thanks so much!! Hopefully the weather in my neck of the woods will clear for a few days so that I can at least make some more progress. I know this is slow going but I have all winter to read and reread everything I've learned so far. If you have time to throw out the other info that would be great too but you have a life as well so I'll be patient until I hear from you again. Thanks!

Life's not quite so easy with $6E. If you change the scalar for one table, without changing the scalar for the next table, there will be a step between one table and the next (assuming there was previously a matching flow rate at the top of one and the bottom of the other). If you want to make everything richer, you can adjust all scalars up, I guess. If you want to richen one portion, you can raise the scalar, then blend the change into the next table. I don't have a 'recommended procedure' yet for doing things, such that they make sense or reduce having to re-do stuff.

I'm still in China (for another year or two), and am on a little vacation, so haven't studied that code section yet, and definitely can't test it on a car, but you can play with it, to see what it wants.

Wow, China huh? Half a world away and you're still answering my questions? Enjoy your vacation and if you get a chance to get back to me that'd be great too. I knew making changes wasn't going to be easy but I get the jist of it now. I'll give it a try this weekend and let you know how some of the changes turn out. Thanks again Jeremy!!!

Well I finally had a chance to play today and noticed the most difference by editing the Accel Enrich %BPW Factor vs. Async Pulse table. I edited the first entry to .85 instead of .50 and this made a lot of difference. The stumble is gone but I'm no where near where I want to be. This car has to have more in it with what I have so I have a ways to go but this is a start. I have no knock counts so the arap timing is perfect for my setup. Hopefully I can bounce some more ideas off of you Jeremy when I get time. Thanks again for your help!

BTW: FTC means Fuel Trim Cell, this is mainly from OBDII terminology, but 3rd gens have FTCs also, we have 16 FTCs and you will "see" them as you drive around. FTCs are number 0 thru 15. At idle you should be in FTC 0. There is a unique Block Learn Memory (BLM) value and Integrator for each FTC. As you drive around (not in AE mode), you move around to different FTCs depending on engine RPM and engine load (MAF flow value).

For good drivibility, you want the BLM value to be near 128 plus/minus 6. If you have the correct fuel injector constant and well defined MAF tables, you should be close to 128.

A BLM value greater than 128 means that the ECM is adding more fuel to correct a preceived lean condition. A BLM value less than 128 means the opposite.

In order to tune properly, you must have an ECM scanner. Do you have one?

And BTW: the FTCs have boundaries according to two tables which you should find in your tuning software. They are arranged in a 4 x 4 pattern:

12 - 13 - 14 - 15
8 - 9 - 10 - 11
4 - 5 - 6 - 7
0 - 1 - 2 - 3

Engine RPM separates the FTCs in the horizontal, and MAF flow separates the FTC in the vertical.

FTC 0 is idle, I'm in FTC 6 when cruising at about 40mph, slight increase in throotle puts me into FTC 10, when I floor it, I'm in FTC 15.

Yep I have a scanner. I'm able to emulate and scan at the same time with the APU1 using TunerPro RT. I don't see an FTC but I do see BLM cells. I have cells 1-16 as you've pointed out but I don't have a way to plot them out as you mention. I don't see anywhere with the 6E.xdf to plot them out with the apap bin. Would that help to be able to do that and do you have a way of how to set it up?

After my new cam, heads and Stealth ram, I had a pretty virgin ARAP, and I would have a horrible lean pop,hessitation with a lil pedal lean in, or at a stop/to WOT.... plenum size, mixed with cc306 cam was harsh on factory AE.

Get the blms in order first. I started with an ARAP bin, and made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.

Tables I changed are: AE decay factor vs coolant temp. Lower the values and the pumpshot wont go away as fast. at operating temp I lowered the values from 39 to 26.

Accel Enrich%BPW Factor vs Async Pulse: Pulse 1 is 3.59, 3.30, 3.20, and 3 for pulse 4-8

the big change happened here: LV8 Accel Enrichment Coolant factor vs coolant temp.
Stock ARAP: 306F(0), 262F(.05), .05, .05, .15, .35, .43, .43, .43
Modifided: 306F(.3), 262F(.03), .35, .35, .35, .35, .35, .40, .40

And my Min Delta %tps for AE Constant is at 3.13,
and the Min Delta LV8 for AE is at 18.

These fueling changes, along with the timing at 26 idle up to 34deg by 3000 gives me excellet throttle response, no stumble, and NO MORE LEAN POP.

Hope this helps. I know I kept making AE changes and it didn't do anything... with the bigger plenum come to find out, you need pretty BIG changes.