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Topic: Using an OBD1 7165 with OSE12P to run an OBD2 Northstar engine. The car is a 1988 Pontiac Fiero, 5 spd transmission.
Resource: Parameter File Printout (in text format) from a stock Northstar OBD2 PCM
Problem: How to make an OBD1 BIN for the 7165 from the OBD2 text file data
Solution:
I copied the text file tables from the OBD2 data one at a time into Excel and through manipulation, interpolation and some guesses, came up with tables that suited the 7165OSE12P format.
For example, for the main timing table for the 7165 I used the OBD2 Main Spark Advance table and correlated 0.08 gm/cyl to 15 kPa and 1.2 gm/cyl to 100 kPa and interpolated everything in-between. The OBD2 chart size was bigger so I interpolated again to get the required number and of rows and columns with the right step size for the 7165 BIN.
The OBD2 charts I manipulated and what I did with them are:
- used “Spark Advance vs Load vs RPM open throttle” table for the 7165 Main Spark table
- used “IAT Spark Advance Correction vs IAT vs MAP” table for the 7165 charge temp advance vs MAT and Temp table
- used “Base spark adv vs Load vs RPM closed throttle” for the 7165 idle spark table
- used“ Cool Comp Spark Advance vs Load vs Coolant temp” for the 7165 coolant advance vrs map table
- used Knock Fast Attack Rate vs RPM data for the 7165 ESC Attack Rate table
- used the Tip-in Max Knock Retard vs RPM to make a guess at the 7165 tip-in bump spark vs tps and rpm table
- used the Main VE vs RPM vs MAP for the 7165 VE 20 to 100 KPa vs MAP and RPM table
Results:
The engine runs quite well, makes good power and is well tuned in the part open to wide open throttle areas. Tuning the engine with the WB O2 sensor and the 7165 OSE12P ecm was quite easy for the part to wide open regions of the VE chart. Tuning the timing chart is just as easy. I am pleased with the 7165 OSE12P ecm and it is a huge improvement over the 7730 that I was trying to tune with before.
Probems:
Yes there are remaining minor problems. There are so many variables in the OSE12P bin that are to date a mystery on how to set up. Without a stock OBD1 bin to start from, these variables have no reference point since many are different in the OBD2 data file. Many of these variable affect the daily driver type drivability more than all out power in WO throttle but they are just as important to get right. They seem to work together and adjustments to one affects the other – so they have to be tuned in unison. Some of these variables are:
A/C related variables including A/C on Map Offset, IAC increment, desired RPM, time delay
Defco related variables
Burst knock retard variables
Tip-in variables
Coolant temp filter coefficient for idle value
Throttle crack and decay rate and hysteresis values, and VE closed throttle vs RPM
Idle spark advance vrs MAP chart
ESC recovery rate chart
And so many more……..

And now the big question if you have read this far – any suggestions for improvements and where to go from here?
It seems I need a stock OBD1 Bin in 7165 OSE12P format for a similar engine to the Northstar so the common variables and charts can be copied into the new Northstar OBD1 BIN. Is that reasonable? If so, what engine would be appropriate to use the BIN from?
I would gladly share my bin with anyone who is working on the same problem – a combined effort might get better results.

PS: I am aware of the 0411 ecm option but I am confident the 7165 12P systems has the capacity to be tuned given the right data. I also like the TunerPro interface and how easy it is to use.

Cheers
Dave.

What capacity and power output is the stock Northstar engine?
The 8 cylinder 12P is a 165kw 5 litre V8.

Dylan wrote:What cakacittand power output is the stock Northstar engine?

I think that is supposed to be capacity, if so here some info.
https://en.wikipedia.org/wiki/Northstar_engine_series

4.6 litres and 300Hp or 220Kw.

They were a very nice engine and I read somewhere many years ago that the AlloyTech V6 is derived from them.

To early on a Sunday to be typing such big words on a phone, quite a good output form a small factory engine.

Post your bin file and a log we'll have a look over it.

Here's my Bin. The engine runs well on it, but it's not perfect. EDIT: updated the BIN. The prior one had the incorrect WBO2 sensor voltage thresholds.

Thanks for having a look.

Perhaps one of the stock bins listed by Delcowizzid on viewtopic.php?f=7&t=3 would be applicable for a good OBD1 reference?

Cheers,
Dave.

Can you post the original bin and XDF you worked from?

The original file I worked from is not a BIN. I worked from a text file of the Calibration Report I found for the engine. I copied it to a MS Word file, attached.
The XDF File I use is also attached.
The Excel sheet for transposing and interpolating the OBD2 data to an OBD1 format is also attached - if you look at it you'll see reference to other tables I used for comparison - these came from the 7730 that sort of ran ok on the engine but was not good for tunability.

Edit: Just read through the Real Time Modded Factory Bins thread and surely there's a bin there close enough to the Caddi Northstar (4.6L 60 deg V8, DOHC) to use and substitute my timing and VE charts and other pertinent variables? But which one? To clarify, the Northstar is a 4.6L 60 deg V8, DOHC, mine is the LD8 variant producing 275 hp and 300 lb.fts. ( The L37 version was cammed and timed a bit different for 300 hp and 295 lb.ft. torque)

All our factory v8s were 5L pushrod, or stroked 5.7 in some HSVs. Your initial approch sounds better. Theres plenty of people of tuning 12p for highly modified engines so with the data you have you should be able to get good results.

I was afraid of that - the Northstar is a nice engine, but a bit of an albatross - not much else like it. I guess the 12P I started with was also meant for pushrod V8 - its what was with the OSE12P setup from the start.
How much different would variables pertaining to defco, a/c intergration, knock retard, cold temp enrichment, be from a pushrod to what I have? The engine runs well but it has enough minor glitches that cumulatively it is not satisfactory - it does not behave like the base tune came from stock. Adjusting some of the variables on a trial and error basis to see the influence leads more to error than good trial - a small improvement in one aspect invariably screws up something else. Seems they all have to be in unison and the task is beyond me. Been tweaking for a couple years now.
How about using these variables from an OHC OBD1 V6? Would that be any better?
Is there any better way to interpret the OBD2 data to the 12P OBD1?

Cheers,
Dave.