Big Spreadsheet for Jeep 4.2 TBI Conversion and other 4.3L V6 Users

Attached is an Excel Spreadsheet that has a COMPLETE* list of all BIN values for the following five BINs:

AKDX
AKSM
AZFT (a 7.4L BIN)
"TUNE15A" - the BIN I am running currently
"Howell 2nd" - one of the files I got from Howell

(* MOSTLY complete - a few obscure values aren't included - see the spreadsheet for details)



I have a 1990 Jeep Wrangler with a 4.2L six cylinder that I converted to TBI using a Howell California legal kit. It ran terribly rich with very stinky exhaust. I have been tuning on it for several months and have made significant progress. Two other threads on this website detail some of my difficulties.

The BIN listed as "TUNE15A" is what I was running when I uploaded this spreadsheet. It is an improvement over the original in many ways, but I would recommend NOT using its fuel tables - it has a hesitation between 800 and 1000 RPMs that I think is caused by a lean condition. Due to a variety of issues I am going to start over with that. What I am running will NOT be the same as the one listed here by the time you see it.


Some of the successes I have had since tuning this thing:

(1) The rich situation is resolved (except for the above exception). My first three datalogging trips had BLMs of 108 in nearly every position - now they are all very close to 128.

(2) I now have a working VSS. Although I had the CA-legal kit that requires a VSS, my harness wasn't equipped for it. Oddly there was a wire labeled VSS for hookup to the speedometer cable converter thing, but it magically disappeared somewhere in the harness - it never made it to the ECM plug. I could not figure out why I couldn't get speed readings despite trying many fixes. Eventually I figured this out, and installed a wire with one of those funky clip things into the ECM plug.

I have a JB Conversions "Super Short" SYE that has no provision for a speedometer cable but rather uses a 40 tooth GM tone wheel. The regular 2-wire GM pickup produces an AC signal, while the ECM needs a square wave signal. To fix this I used a Dakota Digital SGI-5C to perform the signal conversion, and now I have a speed reading from the ECM that matches dead on my regular speedometer reading (which gets its signal from the million tooth tone wheel in my Ford 8.8 Explorer rear end).

I happen to use a Dakota Digital SGI-5C that I bought more than ten years ago when I first installed the TBI kit. To make this work, switches 1 and 2 are OFF (down) and switches 3 and 4 are ON (up). There are two tiny buttons used to fine tune the signal - I messed with these a little bit to get my perfect reading - I have 33" tires and 3.73 gears. Dakota now makes an SGI-5E with a digital readout that might make setup a little easier, but I haven't tried it.

(3) The EGR is now computer controlled. It was controlled by the CTO (coolant temperature overide) valve - a thing on the engine block that prevents vacuum from reaching the EGR until the engine warms up. I simply bought a stock EGR solenoid with a two wire hookup, supplied power to one pin, and attached the other pin to the appropriate terminal on the ECM (had to install another wire with the funky end into the ECM plug). NOTE: this ECM terminal supplies GROUND, not POWER, to the solenoid.

(4) By putting ANOTHER wire into the ECM plug and connecting it to my "Winch Enable" switch, I can raise my idle RPM by 300 when using my winch (the number I chose - you pick whatever you want). This wire goes to the ECM terminal that raises RPM when the A/C is switched on - I have no need for A/C in this Jeep.


Things left to do:

(1) Change ignition timing to ECM control
(2) Fix the lean fuel thing
(3) Change the cylinder head to a 4.0 head, change the header, reroute my exhaust, and tune it all over again.


This spreadsheet will let me compare my programming to other BINs to help me understand this stuff better and make realistic, helpful changes instead of farting around in the dark. Hopefully you can use it as well.


Dan.


*** WARNING: When you open this spreadsheet, click on Enable Editing to change to "Landscape" view - it will either change to Landscape automatically, or you will have to do it yourself in the Page Layout tab. Note that I created this spreadsheet in Excel 2013, but that version saves files in a format not recognized by Gearhead-EFI.com, so I uploaded it as a 1997-2003 ".xls" version. IF YOU DON'T CHANGE TO LANDSCAPE, IT WILL TAKE UP WAY TOO MANY PAGES AND BE HARD TO READ.