I have a 95 7.4 with a $31 bin, the factory idle was too high so I was able to adjust the code for that, but another problem continued.... When your driving along and let off the throttle it stays at ~1200 RPM until I'm almost stopped then it will drop to 600 RPM. This is really annoying and acts like a cruise control.

Is there a secrect to get this to stop?

Thanks,

Lee

 

Yep, it's a secret.
Try looking at the Throttle Follower stuff. My 85 code was like that, and I think there was a T/F decay or some such thing.

 

I'm using the CATS program and there isnt anything like that. I have a feeling that their program doesnt go too deep into the code.

I did find a hacked file on the net ($31_HAC.SRC) but I have no clue how to compile it or make it useable, can you give me some pointers?

Lee

 

Please!

Lee

 

When you get outside the norm, you have to start working with just a hex editor, or generate your own editing files.

So, find a hex editor and look at your current .bin file with it.

Now also in Windows under accesories is a hex to decimal converter.

Once you stare at it for while and look for entry values that line up it will start to make more sense. Tunercat does all the math for you so you have to convert from decimal to hex for it to make sense. Yes, it takes some practice.

Now if you look at these locations you can see where things would effect what your looking at.

And in the hac I have it looks like the 31 cal runs ALOT of low rpm timing, you might pull some timing out of the closed throttle riming tables. Typically ~22 is enough. Go slow take notes.


;---------------------------------------------
; IDLE SA QUALIFIER PARMS
; ECM $31, BNKM
;---------------------------------------------
415A FCB 3 ; 3 MPH MAX FOR IDLE SPK
415B FCB 5 ; 1.9% TPS MAX FOR IDLE SPK
415C FCB 10 ; 3.9% TPS MAX FOR IDLE SPK
415D FCB 64 ; 8 DEG c MIN FOR IDLE SPK
415E FDB 0032 ; SEC MIN RUN TIME FOR IDLE SPK
4160 FCB 0 ; 0 RPM OFFSET TO DESIRED RPM IF NOT AT IDLE
;---------------------------------------------
L46FE FCB 0 ; 0 MPH Vss THRESH TO ENABLE EGR

;---------------------------------------------
; EXTENDED THROTLE CRACKER CALIB'S
;---------------------------------------------
5097 FCB 100 ; 10 SEC'S HOLD HI 4 SEC'S AFTER CLOSING TPS
5098 FCB 10 ; FLOW, IGN OFF, DRIVE & A/C OFF
5099 FCB 8 ; FLOW, IGN OFF, DRIVE & A/C ON
;---------------------------------------------

;---------------------------------------------
; THROTTLE KICKER TYPE $31,
;---------------------------------------------
50C7 FCB 126 ; 55c COOL THRESH MAX FOR THROTTLE KICKER
50C8 FCB 123 ; 48.0% FLOW TO ACCOUNT FOR AIR FLOW IN CALC
50C9 FCB 128 ; 50% FACTOR
50CA FCB 10 ; 10 MPH Vss MAX FOR THROTTLE KICKER
50CB FCB 25 ; 9.7% TPS MAX FOR THROT KICKER
50CC FCB 180 ; 1.8 SEC, MAX RUN TIME FOR THROTTLE KICKER

 

Thanks Grumpy, I do understand that much so far, what I dont know is how this:

1) Is the HAC file just for reference

2) Do you compile the HAC file to a .bin file

3) Use a hex editor directly on the bin file

4) If yes to 3, then what about the checksum I keep reading about

The list goes on, probably more then you care to read. So I think the easiest for me and possibly you is to tell me exactly what software to use from start to finish! I have tunercat and everything to burn the chip....

Lee

 

1) Yes
2) Only with with +-300 hours of work you can manipulate/edit a hac into being source code that'll assemble into a valid .bin
3) Yes
4) Yes, any time you change anything in a .bin file you have to refigure the checksum. ie just run it though Tunercat.

I use Hex Workshop.

 

SLC

Start digging thru the source code and playing around and reading your way thru a hac. Its absolutely invaluable.. Took Bruce about a 3 hr phone call for the lites to come on for me, but once they did its amazing when u can look at a hac and follow your way thru a large majority of it or figure out how changing one variable correlates to all the others ..

Im not a ***(leave that to Grumpy, Rbob, Trax,etc in the source code world) but I've been able to work out many things otherwise impossible with just using your run of the mill editor programs..

Just plan on giving yourself a few hrs straight to sit down and figure it out, the more u do the easier it gets .. When i started this i was cluelss and the closest equivelant traingin i had was basic in highschool 10 yrs ago

later
Jeremy

 

Thanks everyone, it sure helps...

I used tunerpro to edit the .bin file directly which was easy and straight forward, just find the address and change the hex number. When I saved it, it asks if I want to update the checksum and I say yes and all goes well until I put the chip in the car! The check engine light flashes real fast and runs in limp mode. No matter how little of a change I make it still does this.

I suspect the problem is they dont have an .ecu file to match my setup. Do you know of any ecu file for the $31? Or of another program that will work with it?

Thanks for the help...

Lee

 

I believe the fast flashing lightcan mean two things.

1. indicates a non functional Emissions Only device

2. the checksum on the chip isn't accurate, so the computer thinks the PROM is corrupt. This will put you in limp home mode as well.

 

I believe Tunercat has a file that'll work for you.

As far as I know none of the .ecu files anyone's done, has the checksum in the right place for what your working on. The checksum location does move around some, from .bin to .bin..

Open you stock .bin, and record what the values are at the first line in locations 0006, and 0007. Then edit and make a change and see if those two addresses change. If so then the checksum is being updated.
But, just as a sanity check, try changing 0008 from 31 to AA and see if the .bin can be edited and not flash the SES light.