rrubel

Hey all. I'm still in the process of getting a (close-enough-to) perfect bin for my modified '86 4+3. I've gotten a custom one from TPIS that is specifically built for an engine with my setup, but there are a few issues with it still (not all of which are performance-related). I've been comparing it to the stock bin and while most of the fields that are different make perfect sense (mostly A/F and TPS tables), there are a couple of differences that puzzle me. I'm looking at a $32 XDF which was downloaded from moates.net, makers of the APU1 that I'm using.

I'd appreciate some insight into these fields:

1. Addr 0014: AF Opt Wd 1 - Bit 5 - CpCL
2. Gal/hr Inj Flow Rate for display [is set to 0, but dash still provides an instant MPG readout]
3. Addr 02A0: 1st Gear Downshift [this is a manual car]
4. The fan 1 on/fan 2 off values are 00.

Any thoughts would be great... I'm mostly having issues with the overdrive switch not working right, but some of these other values concern me.

Thanks
[RICHR]

tequilaboy

Are you sure that TPIS didn't substitute a $32B or even $6E mask bin instead of $32?

The O/D switch input pin on the ecm is unique for 86, so the overdrive switch issue is a red flag. For 87-88 cars, this same pin is used instead for the first gear switch which is not present on an 86 car.

Try opening the same bin with a $32B.xdf file to see if the data makes more sense. The mask id bytes will look the same (0x32), so that doesn't help.

Post a datalog if you can, in order to determine the prom id, or simply post the prom id if you already have it. It may help identify which bin was used as a starting point, assuming it hasn't already been changed.

rrubel

Thanks for the suggestions.

I checked the data with a $32b xdf; it makes even less sense. I don't have a $6e xdf available.

With a $32 xdf, the prom ID field *says* it's 1E3D; those are the first two bytes of the file. With a $32b, it's 7741 and I have no idea where in the file that's being pulled from.

It would not surprise me if the base file was for a different year; I already was given one earlier for an automatic instead of a 4+3 so they're not 100% on their game at the moment. Is there an easy way to determine that?

I've been wandering around sites like gearhead-efi.com and looking at the various xdf files on there, but those are surprisingly different from what tunerpro supplies.

[RICHR]

tequilaboy

7741 (decimal) = 0x1E3D (hex), so both xdf files show the same prom id and reference the same address (0x00), but one is being displayed as a decimal value, while the other is hex. That is the good news.

That prom id is from a 1987 $32B bin ABTB. MK2 manual 4+3 w-3.07. This explains your overdrive issue due to the shifter switch pin difference and screwy data when viewed with $32.xdf.

32 ABTB 16.00 KB 1987 31576 16070312 1227165 315 7741 YB L98 5.7 MK2 MAN G44

Now you need to determine which path you want to go down, either start over with a real 1986 $32 mask bin, keep the $32B bin and repin the shifter switch at the ecm or edit the bin to read the shifter switch on the current pin (tribal knowledge) effectively making it a 4+4, or pick a better tuner.

rrubel

Hmm. Not sure why I thought both prom ID's were in hex... guess that display is defined by the xdf file.

WRT the tuner, TPIS is probably still the best option for me -- they understand the mods my car has, because they sold and tuned for that setup for years. Now if I can just get them to use the right base... other than the O/D issue, my car hasn't run so well in... well... ever (the engine had issues that I wasn't aware of when I bought it).

Alternately, it should be possible to copy the relevant A/F changes (ignoring ones like fan speed that seem off) to a stock '86 4+3 bin, right? I have one of those.

However... and there always is one... the engine is much closer to an '87 L98 than an '86 one. It's full roller with AL heads (my original engine had iron). Think GM made many changes when they introduced roller rockers in '87? Or did the 5 extra HP just come from the better-moving valvetrain?

Repinning the shifter switch sounds tricky. I've tried tracing wires through that harness and it's quite a mess. I'll assume from your other comment that you don't have the knowledge to change the bin file -- though I wonder if that could be found via diffs between a stock 86 and stock 87 one.

Thanks
[RICHR]

tequilaboy

Re-pinning the shifter switch can be easily done at the ecm connector. Only need to move one wire. I'm too lazy to dig up the pin differences at the moment, but I've posted on this topic several times in the past.

Regarding bin changes to read the existing 86 switch input pin with an 87-88 bin: I developed this approach many years ago in order to provide another tuning option for 86 4+3 cars. By tribal knowledge, I really meant a tribe of one (me), since I don't think I've ever posted the details on how to do this publicly.

Note: this is not meant to be a sales pitch, only informational.

Without the first gear switch, 4+3 operation in an 86 car may still be a bit funky with a $32B bin, since it will try and engage in first gear, unless deactivated by default in the bin, or via the shifter switch.

Another factor to consider is scanning at 8192 baud which can be tricky with $32. DataCat is known to work. I've tested it myself.

If I had an 86 car, I think I would want to stick with a $32 base bin in order to retain the first gear detection logic to allow the 4+3 to operate properly, but I think a $32B bin could be made to work acceptably with the appropriate programming and/or re-pinning as already discussed. Ultimately, the choice is up to you.

Good luck and let me know if I can be of assistance.

Lots of relevant info can be found in this old thread also:
https://www.corvetteforum.com/forums...post1597591789

rrubel

Thanks again. I'll try to get TPIS to send a corrected bin; if they keep failing at that then I'll probably look into the wiring harness change.

[RICHR]

tequilaboy

If you want to post or send me your current bin, I will fix the overdrive switch input for you to evaluate. I think this is the simplest solution.

rrubel

PM sent with d/l link.
Thanks
[RICHR]

tequilaboy

Check your email. I've made the following changes:

Edit Log for RichRubelABTB082119_OD.bin created by TunerPro.
**************************************** **********************************
09/08/2019 14:37:28 Scalar: Prom ID changed from 0x1E3D (0x1E3D) to 0x1E3E (0x1E3E).
09/08/2019 14:37:37 Flag: 4+3 Overdrive Default Off/On (Set = On) changed from Set to Not Set..
09/08/2019 14:37:56 Flag: 4+3 Overdrive Switch Input 1. Set only for 1987-88 (bit 1). changed from Set to Not Set..
09/08/2019 14:38:28 Flag: 4+3 Overdrive Switch Input 1. Set only for 1986 (bit 2). changed from Not Set to Set..
09/08/2019 14:38:33 Flag: 4+3 Overdrive Switch Input 2. Set only for 1987-88 (bit1). changed from Set to Not Set..
09/08/2019 14:38:47 Flag: 4+3 Overdrive Switch Input 2. Set only for 1986 (bit 2). changed from Not Set to Set..

rrubel

Thanks! I should be able to burn a chip and test it early in the week, but this sounds like exactly what I needed. You are awesome.
[RICHR]

tequilaboy

Check your email. I sent you a new updated bin.

After reviewing the code again, I changed a few more bits in order to avoid false detection of first gear while the OD switch is pressed.

Edit Log for RichRubelABTB082119_OD1.bin created by TunerPro.
**************************************** **********************************
09/08/2019 21:46:56 Scalar: Prom ID changed from 0x1E3E (0x1E3E) to 0x1E3F (0x1E3F).
09/08/2019 21:48:51 Flag: 4+3 First Gear Switch Input 1. Set only for 1987-88 (bit 2). changed from Set to Not Set..
09/08/2019 21:48:52 Flag: 4+3 First Gear Switch Input 2. Set only for 1987-88 (bit 2). changed from Set to Not Set..
09/08/2019 21:48:53 Flag: 4+3 First Gear Switch Input 3. Set only for 1987-88 (bit 2). changed from Set to Not Set..
09/08/2019 21:49:24 Flag: 4+3 First Gear Switch Input 1. Set only for 86 (bit 1). changed from Not Set to Set..
09/08/2019 21:49:25 Flag: 4+3 First Gear Switch Input 2. Set only for 86 (bit 1). changed from Not Set to Set..
09/08/2019 21:49:26 Flag: 4+3 First Gear Switch Input 3. Set only for 86 (bit 1). changed from Not Set to Set..