Spark Advance in Diacom
Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,083
Likes: 0
From: Spanish Fork Utah
Spark Advance in Diacom
Gentlemen,
I have an 1985 - 1226870 ECM
My spark advance in Diacom reads "0" all the time through a recording. Is there a table somewhere in C.A.T.S. that needs to be programmed in order for this field to populate while driving?
I have unplugged the computer from the timing and made sure it was set to 6* advanced, then plugged it back in. Then during revving, the timing mark does go way up the harmonic balancer. Probably 20*-30*, So I know that the timing is being advanced by the computer.
[Modified by sspackman, 12:59 AM 11/9/2003]
I have an 1985 - 1226870 ECM
My spark advance in Diacom reads "0" all the time through a recording. Is there a table somewhere in C.A.T.S. that needs to be programmed in order for this field to populate while driving?
I have unplugged the computer from the timing and made sure it was set to 6* advanced, then plugged it back in. Then during revving, the timing mark does go way up the harmonic balancer. Probably 20*-30*, So I know that the timing is being advanced by the computer.
[Modified by sspackman, 12:59 AM 11/9/2003]
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: Spark Advance in Diacom (sspackman)
Diacom will not correctly report spark advance on an '85. Been there, done that. It ticked me off, but there is a way around it.
You mentioned you had CATS. You will need a little more than just that, however. A HEX editor that you can modify stuff not shown in TunerCat.
What you are going to do:
Modify the code so that Diacom reports the timing where it usually reports the PROM ID. Spark advance will still show 0 on Diacom, however, the PROM ID will update.
Do a search over at thirdgen.org in the PROM burning section, because I believe that is where I saw it posted up.
Well, read this one, then do a search. It can't do a search on 'ID' because the query is too short. <A HREF="http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=81908&highlig ht=PROM+Advance+data" TARGET="_blank">http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=81908&highlig ht=PROM+Advance+data</A>
It gives the basic idea of how to do it. Good luck, -Matt
Edit-BTW, with the scanning modes available for '85 (ALDL and Diagnostic), I believe both modes actually add a bit more spark advance than when the scanner is not connected.
[Modified by HighHopes85, 8:31 PM 10/1/2003]
You mentioned you had CATS. You will need a little more than just that, however. A HEX editor that you can modify stuff not shown in TunerCat.
What you are going to do:
Modify the code so that Diacom reports the timing where it usually reports the PROM ID. Spark advance will still show 0 on Diacom, however, the PROM ID will update.
Do a search over at thirdgen.org in the PROM burning section, because I believe that is where I saw it posted up.
Well, read this one, then do a search. It can't do a search on 'ID' because the query is too short. <A HREF="http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=81908&highlig ht=PROM+Advance+data" TARGET="_blank">http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=81908&highlig ht=PROM+Advance+data</A>
It gives the basic idea of how to do it. Good luck, -Matt
Edit-BTW, with the scanning modes available for '85 (ALDL and Diagnostic), I believe both modes actually add a bit more spark advance than when the scanner is not connected.
[Modified by HighHopes85, 8:31 PM 10/1/2003]
Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,083
Likes: 0
From: Spanish Fork Utah
Re: Spark Advance in Diacom (HighHopes85)
Thanks for answering my post so quickly. I really appreciate it. I will give that a shot and see what happens.
Does the TunerCat table that is "Spark Advance Vs. RPM Vs. Load" have anything to do with this? Also, that particular table only goes up to 4800 RPM. Isn't that really weird?
Thanks,
Shayne
Does the TunerCat table that is "Spark Advance Vs. RPM Vs. Load" have anything to do with this? Also, that particular table only goes up to 4800 RPM. Isn't that really weird?
Thanks,
Shayne
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: Spark Advance in Diacom (sspackman)
Does the TunerCat table that is "Spark Advance Vs. RPM Vs. Load" have anything to do with this? Also, that particular table only goes up to 4800 RPM. Isn't that really weird?
As far as it only going up to 4800 RPM, it isn't really all that odd. For all intensive purposes, you had already peaked torque with the engine as it was from the factory, so spark was just going to continue with whatever it was from that point on. If you compare it to a conventional weight-and-vacuum advance distributor, it is pretty much the same concept.
However, you still have fuel control (up to 6400 it looks like). That leads me even more to believe that spark was meant to remain at it's last point that it was at from 4800 and up.
Also, just for comparison with a later-model BIN (a calibration for a '91 F-body), there is a table called "Main spark adv vs RPM vs Load . It has an entry for spark at 4800, 5200, and 5600. The factory uses the same spark values for all the RPMs in the same load region (exactly what yours is going to be doing even though you don't have an extended table).
Lemme know if I can help out any more. It's been a while since I messed with the BIN from an 85.
Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,083
Likes: 0
From: Spanish Fork Utah
Re: Spark Advance in Diacom (HighHopes85)
Hey guys,
I'm going to give it another chance to get that Spark Advance table to show up in my PROM ID field. I've read through the Thirdgen stuff and am actively pursuing it. Can you recommend a good reliable hex editor?
[EDIT] I'm definitely going to need some help doing the first .bin file. I'm sure I can handle it from there.
Thanks,
Shayne
[Modified by sspackman, 12:59 AM 11/9/2003]
I'm going to give it another chance to get that Spark Advance table to show up in my PROM ID field. I've read through the Thirdgen stuff and am actively pursuing it. Can you recommend a good reliable hex editor?
[EDIT] I'm definitely going to need some help doing the first .bin file. I'm sure I can handle it from there.
Thanks,
Shayne
[Modified by sspackman, 12:59 AM 11/9/2003]
Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,083
Likes: 0
From: Spanish Fork Utah
Re: Spark Advance in Diacom (HighHopes85)
They are charging 24.99 for it now. Figures. Do you still have the freeware edition hanging around somewhere? If so, could you send it to msspack@yahoo.com?
Thanks HighHopes85. I'm getting pretty serious about picking up that Romulator, but I'm going to have to switch out my fuel injectors for the 24# ones from the 30# ones in there now to get a closer tune. Ouch. Looks like it's time to order more gaskets!!!
Thanks HighHopes85. I'm getting pretty serious about picking up that Romulator, but I'm going to have to switch out my fuel injectors for the 24# ones from the 30# ones in there now to get a closer tune. Ouch. Looks like it's time to order more gaskets!!!
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: Spark Advance in Diacom (sspackman)
http://download.com.com/3120-20-0.ht...search=+Go%21+
The editor is free...I've never used the disassembler. If you need to disassemble for it, TunerCat has a 30 day free trial.
The editor is free...I've never used the disassembler. If you need to disassemble for it, TunerCat has a 30 day free trial.
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Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,083
Likes: 0
From: Spanish Fork Utah
Re: Spark Advance in Diacom (HighHopes85)
http://download.com.com/3120-20-0.ht...search=+Go%21+
The editor is free...I've never used the disassembler. If you need to disassemble for it, TunerCat has a 30 day free trial.
The editor is free...I've never used the disassembler. If you need to disassemble for it, TunerCat has a 30 day free trial.
Take care,
Shayne