1228747 C.A.T.S. vs TunerPro difference in ECM Mask / *.xdf file??????

[EagleMark]

Narrow band is a very b ad way to check that, most ECM it's not even working in PE, PE is closed loop so no INT/STFT or BLM/LTFT it just reads the last thing it saw before going into PE.

[51caddyman]

OK that is very good to know... I'll add that to my next list of parts to buy, I was thinking of stealth mounting one inside my driver's side faux spot light, as putting a digital gauge on the dash of a 51 would go against the "look" I'm after; most (lay-people) see the motor and think it's a carb anyways... Exactly what I'm going for... Sneaky. Should I fatten up the fuel 1% at a time and keep trying? All the spark plugs look very good, not lean or rich looking.

[EagleMark]

Do you have data logs of this?

You said"showing 121-126" I'm assuming a BLM or INT number... it's wrong at WOT in open loop. Now some ECM/PCM will stop cross counts in O2 sensor and you can get a steady reading, should be upper end like .850, not .121! This is just an idea! Not a good measurment!

I love the look!~ Sweet car! If you get it right you can take out the Wide Band, don't even need a gauge if you can log data with laptop and LogWorks! Or find a way to plumb it into the 12288747... then data stream, not sure if there is a usable AD port.

With the raised fuel pressure did you calculate and update the BPW?

[51caddyman]

OK sorry went home and played with things for a while making tiny tweaks and seeing if I could get bunch more data for you so first off here are the logs

as you stated i thought I'd try a tad more fuel and see so to 70-90 I (4800RPM) added 1% more fuel from my best to date tune:

32.jpg
Feel wise it felt about the same, maybe a tiny bit rougher. So just to be sure I added anther 1%, but that made it worse feel wise as well:


33.jpg

[51caddyman]

So I reloaded my starting BIN again and took 1% of fuel back and got this, feeling best up to 4800 as well, but still breaking up beyond that. Sorry I'm new to all this but what's the BPW? Darren got this this tune pretty close except for the higher RPM stuff, as I just added the governor mod kit from B & M to raise my shift point over the factory 4000 RPM:
34.jpg

[dave w]

Those look like WinALDL Screen Shots? I'm thinking the Wide 10 Average is showing Rich fuel mixtures in most places.

I'm better with TunerPRO RT .xdl files. The '8747 is a good ECM. In some ways I think the '8747 is better than the popular '7747.

dave w

[1project2many]

She's pulling very nicely all the way up to 4800K RPM

I don't have much to add except that anyone who can get a smallblock Chevy with TBI to pull all the way to four million eight hundred thousand rpm should be on the DIY nuclear particle collider board. ;)

Spark timing needs to increase as rpm increases. I don't have TP here to view the definitions but there should be a constant for spark rate, or high rpm spark ramp which usually needs to be adjusted to increase advance. The ecm will continue to add advance to the values in the highest RPM table as rpm increases at the rate entered in the constant. At WOT the 100kPa value is used as the basis. Since a stock TBI power curve usually starts to fall off where your engine is making power GM is usually conservative here. Without the right spark advance, no amount of fuel changes will make things right.

[51caddyman]

HA HA!!! sorry 48K OR 4800... And I agree with you, after another set of pulls this am on the way to work i'm showing 127 in the BLM for 60-80KA at 4400-4800. It's got to be spark now...

[EagleMark]

The '8747 is a good ECM. In some ways I think the '8747 is better than the popular '7747.

dave w

It's got bigger spark and fuel tables so that is better, but all else is same ECM. Problem is all the development went into 7747 because there are so many more of them. There's not much you can't do with a 7747.

Now here's one problem with 8747 and in 51Caddyman case a big problem. I know how to fix it in 7747, just run the ESC done patch and no more force knock test, no more PE delay.

How'd you like to have a monster motor build and the knock sensor may not be accurate or even work? Now you get the ESC test and it adds 11 degrees timing expecting a knock count? No knock count? No problem just add 22 degrees timing! He's at a tuning point where this could cause disaster! WIthout a wideband he'll never be able to see it happening, without a Spark Advance hack to see timing can't see it there either?

Have to find a way to test after adding one of these paremeters to the bin definition to get the test to stop!

  ;---------------------------------------------
        ; ERROR 43
        ;
        ; KNOCK FAIL
        ;---------------------------------------------
LD5A7   FCB  60     ; Min time since run enable, (120 sec)
LD5A8   FCB  235    ; PA count limit
LD5A9   FCB  23     ; EST fail test period, (2.3 sec)
LD5AA   FCB  3      ; 3 SEC's  ??
        ;---------------------------------------------
        ;---------------------------------------------
        ;
        ;
        ;---------------------------------------------
LD5AB   FCB  55     ;        
LD5AC   FCB  34   ;
        ;---------------------------------------------
        
        ;------------------------------
        ; ERR 43 PARAM'S
        ; KNOCK DET ERROR
        ;------------------------------
LD5AD   FCB  255    ; 99.6% TPS PWR ENR BYPASS ASSUM PWR ENR CONDITION
LD5AE   FCB  128    ; 3200 RPM UPPER LMT FOR ERR 43 TEST
LD5AF   FCB  195    ; 81 Kpa LOWER LMT FOR ERR 43 TEST 
     ;
LD5B0   FCB  34     ; 12 DEG SPK PWR ENR ADD TO CAUSE KNOCK 
LD5B1   FCB  63     ; 22 DEG SPK PWR ENR ADD TO CAUSE KNOCK, 2nd MODE PE
LD5B2   FCB  2      ; 2 KNOCKS, KNOCK LMT MIN (12.5 Msec Period's)