There is a provision for changing the delay in tunercat. Also, the dfco is necessary, all cars have it. It is not used on the freeway because you are at a constant throttle and never on decel so it wouldn't affect freeway mileage. Also, a car under decel should make more vacuum than when you are about to shift. Log your vacuum at all those points and adjust it acordingly... I have a feeling that if it was turning on while shifting or on low speed decel it was set up wrong. I find the DFCO makes the car run and sound a lot cleaner but I guess it's up to you.

DANSEAN1:

BLM stands for block learn multiplier. See the computer sees a full range of rpm vs. map values and separates them into 16 cells. For example, cell x is from w-x rpm and y-z kPa. Then there is something called a short term integrator (INT). This is the real time correction factor based on your o2 reading that the computer needs to achieve 14.7 a/f ratio. When the INT detecs a ratio that is off, it starts adding or subtracting fuel. The BLM responds to the integrator by slowly adjust the permanent fueling for that cell. So if you are always lean, and the INT keeps saying lean lean lean for a few hours of driving, your BLM will indicate a lean condtion in that cell. I probably confused you more... it's sort of like the car's memory. After it the INT tells it a bunch of times that the car is running a certain way in a certain cell, it start remembering it. There is a tutorial on para.noid.org/~lj (contains the stock cell table too)

Only is rare cases would you need to adjust the MAF calibration table. If you do, you must keep the curve perfectly smooth. View the table in graph mode and you will see that all those obscure decimal points are part of a very smooth curve. To adjust fuel you are better off using the volumetric efficiency tables but if you find yourself having to make huge changes there is probably something else wrong with the car other than bad tuning.

LT1 tuning is much more complex than a single PE chart. To answer this question I'd have to tell you how to tune... just look at the table in tunercat, especially all the constants and timing tables.

When tuning for WOT, you should leave the temp table alone to minimize variables. Only adjust one table.

 

Where do I find this in tunercat?

 

In the constants list near the other DFCO stuff.

 

Just another update here. Concerning my comments regarding the Open Loop AFR table. First time around I added 10% to the values in the table from 80 KPA and down and saw no discernable difference. 2nd time around I added 20% and it definitely leaned things out, a little too much. So it works after all, at first I thought it didn't make any difference. At low loads I was seeing like .100's so it definitely leaned it a bit too far lol. Despite that the surge wasn't really all that bad, so the .100 number probably isn't as lean as it suggests. Looks like my idea is going to work, only, I will use the AFR table instead of the MAF. I will add 15% next time to see if that's about what it likes since that's inbetween my last two changes. When I say adding I mean adding a % to the values in the AFR table to make it higher/leaner ....looks like about 10-15% is what may work best for me. Tell ya what though, it only takes a little bit of throttle to get to 80+ KPA and it goes right to .960 mv's when I do that, I may lean the whole thing down including 80 - 100 KPA. When I'm on the gas as normal the O2's are hovering around .700 ....I think this is very good based on what I've heard about O2 vs AFR. Like I said I'm not shooting for 14.7:1 though, just close enough but rich enough to give the engine what it wants that's all.

 

You guys have inspired me to do some open loop tuning as well. I have a Dynojet wideband installed on my car so it is pretty easy. First thing is to change the closed loop enable temp to maximum. Next I changed my open afr table so that all coolant temperatures numbers are the same. Now I only have 2 variables MAP and RPM. Initial wideband readings were all .5 higher than the table would suggest. For instance 14.0 in the AFR table would give 14.5 AFR on the wideband.

After adjusting the AFR until there was no hint of cam surge my wideband said 13.5 AFR. The car runs smoother between 1500 and 2500 rpm and less than 60 Kpa(Cam problem area). I saw no change in idle vacuum and generally runs the same. Now all I need to do is run a tank of gas through it and find out what my Mileage is.

 

Have not chimed in in a while, been super busy. You guys have provided me with some very useful info, thanks. I appreciate it.

I sort of get the INT and BLMS, I guess I will eventually.

Have any of you ever adjusted the shift points in mph in LT1 edit, specifically for WOT? I put in a tune i found off of Brent Frankers website, a tune that closely matches my car. I ran the tune for a couple days and found I liked certain things and others not so much. I then took my very last old tune and custom made one of my own. Even with the new one I want to adjust the shift points vs. mph. I guess its best to do one small change at a time till you are happy?
Also, on the web tune I got, on the MAF calibration table, there was a spike or "unsmoothness" to a certain portion of it. I dont think it affected my car but I have heard from you guys and others that that table or maf stuff must very smooth.

I was thinking of getting a wideband 02, either the dynojet or LM1. The dynojet seems good but expensive, however, with all the add ons with LM1, the dynojet is the best.
Can the dynojet be portable although its made to be installed permanently. I would like to use an AFR tuner on muliple cars. Any ideas.

There is so much to learn!!! I thought I knew a lot and then there is so much more.

Thanks
Daniel

 

I got my dynojet wideband on ebay for about $375. It is not easily portable because of the wiring but could in a pinch be used on multiple cars. I still have not been able to make the tach input work with my delteq. I sent the dynojet AFR guage to autometer and they changed the silver bezel for a black one which matches the interior perfect.

 

You have a lot of options for the wideband system, most of them are proven. The dynojet commander is a nice piece. The innovate is the cheapest but does not log unless you hook up the cable to a laptop. I am using the Zeitronix with the added LCD display. It shows up to 4 inputs (TPS, MAP, tach or whatever else, and boost or EGT if you have an EGT probe and a 3.5 bar map respectively). Then there is the PLX m550 which IMO is one of the best. The functionality and the datalogging capability is probably the best. Then there is the TechEdge. I have seen a few people on the board using them and I think one has been posted for sale recently in the classifieds. Any way you go, the wideband will open up a whole new world of personal tuning.

Pilot - I'm really interested to see how this goes with your car. So you basically made each row the same value all the way across. That makes sense... But you still have MAP and RPM that are not accounted for in the open loop table. What takes care of that? MAF tables? Do you feel that the car runs better in open, or closed loop?

 

I'm running into some setbacks on my open loop tune. When the car is cold it shows different AFR's on the wideband. There is another table somewhere that is adjusting the AFR when the engine is cold in open loop.

As mentioned before, I took coolant temp out of the equation on the Coolant Temp vs MAP AFR. So Map's are accounted for in this table. I have not figured out how to adjust for different RPM yet.

I suspect there is a table where IAT's adjust open loop AFR but I have not had time to track it down. More work to do.

I have found out that low rpms give a lower Open Loop AFR. So I have to figure out how to fix this.

This is what I found out:

1. There is no doubt that PE mode is active in open loop.
2. VE tables have no effect in open loop. My VE tables are only used in speed density mode.
3. A 14.0 AFR in the cam surge areas is as lean as I can go and have no hint of cam surge.
4. The Maf Calibration Table is very effective and sensitive in changing AFR in open loop. I have chosen to leave this table alone until I get everything else set right first.

 

I am running my 94 FW LT1 in open loop with so far pretty good (not perfect) drivability. I am pushing it without a WB O2. Wish I had access to one. I see around 25-35mV average on the NBO2 while cruising. I am avoiding EGR right now, don't need to add mess to the mix....

I agree, leaving the MAF cal alone I feel is best. I don't think it ever should be messed with unless you can recal it with your exact setup, not tweak and mess with it to bandaid something else that isn't right. It needs to know exactly how much air is passing though, not what you want it to read, it needs to be exact.

 

"MAT modifier to MAF vs MAT"
MAT = Manifold Air Temp. This table dictates how air temp changes the PCM's interpretation of MAF readings. This would affect AFR w/o O2 feedback, possibly if the MAF or intake tract has been modified from stock calibration/configuration...?

 

I thought about that table but in the stock calibration it is only used at really cold temps like below freezing. All the settings above freezing(or thereabouts) were set to zero. I may have to give it a try.

 

I believe I have finally worked out all the bugs in my open loop tune. I have the AFR at 14.0 at light throttle and and as low as 13.2 at medium throttle. I have WOT set to 11.8. I have the idle AFR set at 16.0. The car runs and sounds much better at these lower AFR's especially in the cam surge areas. Low end torque and driveability are greatly enhanced.

I drove 700 miles from LA(Lower Alabama) to Kentucky yesterday at highway speeds of 70-80 mph and I got 23 mpg. In closed loop I got 25 mpg at the same speeds. So I picked up driveability and gave up a little gas mileage on the highway. In the city my mpg difference is negligible closed loop vs open loop.

This took me at least five hours of tuning to get the Coolant Temp vs Map Open loop AFR table right. Without a wideband I beleive it would be beyond my capability. I also had to adjust the injector offset vs battery voltage. I subtracted 50 across the board. This made my idle leaner and didn't really affect light to medium throttle at all. It also made closed throttle coasting leaner.

The MAF Table was left completely stock.

 

Why did you have to adjust injector offset vs battery voltage? Does that modify pulsewidth or injector timing?

 

It modifies injector pulsewidth. It is very effective at low pulse widths and not very effective at high pulse width. Some people adjust it when they get very large injectors. It is sort of like modifying the injector constant but only at small pulse width. LJ's tutorial gives a better expanation.

http://para.noid.org/~lj/PCM%20Tutorial/PCMtutorial.htm

Here is an excert from his definitions page.

Offset: Going back to the scale example I used to describe correction factor, suppose some joker changes the doctor's scale so that it reads 5 lbs when nothing is on it. If he remembers to subtract 5 lbs from every reading, the results would all be perfectly accurate. This is the same as subtracting an offset from the reading. Remember that correction factors are multiplied (or divided), but offsets are added (or subtracted).

Again referring back to correction factor, note that the relative size of an offset is huge when the "right" number is small. If you weighed a 1-ounce letter on the doctor's scale after the joker messed it up, the scale would report roughly 5.06 lbs. The absolute error of 5 lbs results in a relative error of 5 / 0.06 = 83.3 = 8333%! But the 5 lb error in your 200 lb weight causes just a 5 / 200 = 0.025 = 2.5% error