ODB1 ECU Project - Page 9 - Tuning Forum

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Re: ODB1 ECU Project
Saturday, September 05, 2009 7:58 AM
Turn your boost down to 14psi and tune for that on 440's. Let me know if you need an updated XDF too, it has an injector size constant you can set.
I hear Brandon's pretty smart when it comes to tuning, it doesn't surprise me he was able to do it with your logs.

You should also run a few runs with Scannerpro running and open loop mode then send him thoes logs. I bet he could get your VE dialed in so precise that learn mode never has to kick in.

Re: ODB1 ECU Project
Monday, March 29, 2010 7:49 PM
ok i have been playing with this since a couple of days and for the first time i can read
the bin fine. now i have a couple questions... (sorry for my ignorance)
havent tried this on the car yet since its still snowing outside

1-there is 3 VE table two of them from 800 to 4k rpm, one is single fire and the other is double fire.
whats the difference?

2-why is the table from single and double fire goes to 100kpa but the other one which is 4k to 7200rpm, stop at 90kpa?
is this normal? also cant we go higher than 7200rpm?

3-how to disable close loop, the easiest way?

4-whats injector constant with brown top? from mantapart bin its set a 128 and stock at 20!!! how do i calculate this?

5-why PE stops at 6k rpm and goes up to 130kpa? wouldn't 100 be the max?

6-whats the difference between accel enrichment and power enrichment?

7-i notice there is some duplicated maps like PE AFR vs coolant temp and idle rpm vs coolant temp.
if i would have to change these, will i have the change data in both?

8-in table PE enable TPS vs RPM, why is it baro (high, low) vs tps? no rpm and only 2 value of 80%

9-how to add the WB to the adx file with tunerpro V5. i have found the how to from moates.net but its for previous version
and im not sure of all the values.

10-whats MAT? manifold air temp? if so, is IAT the same?

Also C. Smith, would you send me your most recent xdf and adx file pleasee?
thanx for all the help

Re: ODB1 ECU Project
Tuesday, March 30, 2010 9:05 AM
I have not had a chance to look into this for quite some time. I had kids and my research got put on hold.
I'll try to dig out my latest files for you and take a closer look.
Re: ODB1 ECU Project
Tuesday, March 30, 2010 8:27 PM
ok i understand! if you could send me your latest file that would be awesome. i have now your beta3 xdf.
also when you have time if you can answer my question, that would help me alot.
thanx again!

Re: ODB1 ECU Project
Wednesday, April 07, 2010 6:53 PM
any update? found those latest files?
let me know thanx

Re: ODB1 ECU Project
Thursday, April 08, 2010 10:15 AM
Its sad to say but you have my latest files.

I will have to load up tunerpro 5 and my latest files and do some clean up/upgrade work.

To eliminate closed loop, you should be able to set the open to closed loop thresholds high enough that the computer never gets there. I'll take a look when I get my files loading up on this machine and see exactly how to do it then post.
Re: ODB1 ECU Project
Thursday, April 08, 2010 1:44 PM
ok. also what about the injector constant? if i remember right you said you could integrate it in cc or lb/hr.... that would be great since now i have no idea how to calculate the constant. it doesn't seem to be like hpt. and that is the first thing i would like to change before i go and play with the tables.
thanx again

Re: ODB1 ECU Project
Sunday, April 11, 2010 5:16 PM
So this never got finished? Or is it ready to install an obd1 ecm into a obd2 vehicle?
Re: ODB1 ECU Project
Sunday, April 11, 2010 5:20 PM
I have a 98 S-10 with a turbo and am gettin ready to do something about tuning after driving it for 2.5 yrs with no tune. Hp tuners and alpha-n dont look to good for boost tuning. Need something different I thought this setup with the obd1 was gonna be the hot ticket.
Re: ODB1 ECU Project
Sunday, April 11, 2010 6:03 PM
Hope it works out
Re: ODB1 ECU Project
Monday, April 12, 2010 8:32 AM
The ODB1 ecu is able to tune but why would you want to if you have hp tuners. I was under the impression that HP Tuners can be set up for speed density.

The odb1 ecu is a speed density ecu, so it would work great for your project, and yes all the graphs that you would need to work with are there.
The major problem here would be that you'll need to understand machine code in order to work with it. It's not a easy to use GUI, rather you have to understand how the ECU code works in order to tune with it.

While TunerCAT and TunerPRO make this easier, they don't make it simple.

Re: ODB1 ECU Project
Monday, April 12, 2010 3:18 PM
I meant I dont have hp tuners yet
Re: ODB1 ECU Project
Monday, April 12, 2010 7:54 PM
can you explain me the formula for the injector constant in that pcm please?

Re: ODB1 ECU Project
Friday, April 16, 2010 2:33 PM
-To be honest it's a caluculation of best guess estimate based upon available data for our cars. Since the PCM is an unexplored territory, I had to calculate it blind. If you set it to your injectors, does it seem to work as set, or does it seem off. If you can get me the factor it is off by that will allow me to recalculate the constant to be more accurate.

This is also based off of past pcm work.
Re: ODB1 ECU Project
Friday, April 16, 2010 2:38 PM
I'm considering putting together a website where we can all colaborate on the free and public domain design of the .xdf files. My question is, does anyone know of any webspace that is readily available where we could post files and such. I was considering yahoo like the DSM guys use.
Any ideas? This PCM when purchased at auto wrecking yards is $50 bucks with harness clips and would be a very viable replacement for even someone using Megasquirt if we could iron out details!!
Re: ODB1 ECU Project
Friday, April 16, 2010 7:52 PM
Other than Moates FTP section, I don't know of anything offhand unless someone is willing to put up their own host and allow access to it. Add to that I realy don't know the 0s and 1s of that stuff. Although I don't think its possible, it would be awsome if it could be setup for more than 4 cylinders. Unfortunately I don't think this computer was used to run anything but 4 cylinders and I'm assuming it doens't have the spare drivers for fuel injectors or coils?

13.934 @ 97.82 ALL MOTOR
Re: ODB1 ECU Project
Sunday, April 18, 2010 3:11 PM
I believe this ECU could easily be set up for 6 or 8 cylinder. The code is very similar to what is used in the chevy S10's but more importantly the driver chips for injector firing could fire 2, 3, or 4 cylinders at the same time.
It isn't set up for sequential injection though.

As for ECU code, it's all hex. But more importantly when put through a disassembler it becomes machine code, which isn't 1's and 0's but more closely related to boolean logic.

My reason for wanting to post what I have public is so that others can take over where I left off. I got this far with help from others with more knowledge than me, and I learned a lot.
Now if we had the whole internet community dig into this, my guess is that we could 100% crack this unit and build custom code for it. Thats where the gold is at.
Re: ODB1 ECU Project
Saturday, May 08, 2010 1:39 AM
For everyone wanting to know how to force open loop, I believe we can do it by setting any of the high open loop settings to a low number.

Has anyone played with the open loop parameters in my xdf? I think it will be really easy for force open loop as this PCM generally operates in closed loop.

I am currently working with tuner pro v5 on a new definition file that will accurately work with tp5.
Re: ODB1 ECU Project
Thursday, May 13, 2010 12:50 PM
I played with forcing open loop last night and what you need to do is open up my bin with my xdf, and set the HOT Closed Loop Timer to 9999. Make sure the car is warmed first and this will make the PCM go into open loop until the timer hits 9999 seconds. If tuning for cold, look for the Cold Closed Loop Timer, and up it from 180 sec to 9999.

I successfully ran my NA ride last night in open loop with a fairly accurate tune, and discovered the factory tune runs WAY to rich!!
Re: ODB1 ECU Project
Thursday, May 13, 2010 1:11 PM
good to know, i will test this as soon as i have time....
thanx for keeping the good work on this ecu

Re: ODB1 ECU Project
Thursday, May 13, 2010 2:09 PM
I have a little bit more time to work on this now that I am going to be driving my NA ride again.

I've had a bit of success with AFR calculations on the narrowband, tho not really accurate out side of 14.7 it has been close.
Also having some luck with PE tables as well. Now if I can just figure out how to install larger side feed injectors and a fuel delivery system, I could install my turbo.

Re: ODB1 ECU Project
Sunday, June 06, 2010 5:04 PM
I just unplugged the narowband wire..... kinda the easy way.

When i got rid of it, it would chew up my GTO, I sold it with a safe burn of a prom, enter boost, no were near what it wanted for timing, but it was safe to drive a distance with out cracking a head, ( two cracks in the head, typical 086 loc too, plug to valve seat, and a nice burn mark across two pistons # 3 and 4 both twards each other. nice 1/4 gap in the gasket too.)

But the one that I gave you guys that i put "unsafe" on, was the fast one, the one that I said, "use this one" was the one that had crappy timing. Given a hybrid of them, it would be both fast and safe... alas thats the trick of it is it not?

Good luck everyone.


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: ODB1 ECU Project
Monday, June 28, 2010 4:39 PM
So i'm trying a different aspect with the project this summer. Tuning for fuel economy on NA.
Any ideas as to how i can tune this out, i've always tuned for power and tuning for economy isn't working as well as i thought.

Though process = reverse power mods, lean out fuel and timing, limit air flow....
So far, im having issues getting any economy out of it.
Re: ODB1 ECU Project
Tuesday, July 27, 2010 3:50 PM
is there an tach signal output on the 95 ecu? i would like to connect a gauge.

Re: ODB1 ECU Project
Tuesday, July 27, 2010 3:59 PM
Yes Magik, check the users manual for the specific output wire. I believe it's green, I can't remember.
The big problem with the TAC signal is that our cars normally require a special adapter to use any kind of TACH.

I was able to tear apart my auto meter, and re-soldier an extra varistor into the mix to properly adjust it, but it does jump a bit.
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