Cyl Displacement

[Superdave]

Yes


Does your trans have a VSS output or is it cable?

[Canyonero]

I have a VSS in the speedometer which was buffered to 2000ppm square-wave/digital for the old ECU. I assume the VSS is natively 4000ppm square. It is still used for the factory cruise control (pre-buffer). I have a cable driven 4000ppm sine-wave/analog VSS ordered, which I should have had two weeks ago...

I've been driving the past year with no VSS at all.

[ForcedFirebird]

The stock $88 will run the 3.4 no problem if you were using the distributor. Lots of guys on TGO have swapped a 3.4 in and they run just fine with no changes.

Since you kept the 3.4 manifolds, you now have DIS and agree, you should use $A1.

[Canyonero]

I'll switch over to the 3.1 manifolds when I install my cam, one thing at a time. I was planning on retaining DIS regardless. Which should I use, ARUR or BFUZ?

[Superdave]

BFUZ, that's what the one i sent is based on.

[Canyonero]

Awesome. But why that one?

I hope these chips take many erase/write cycles, I've already flashed it a half a dozen times and I don't even have the wiring installed yet (forgot to put the AIR connector in, doing that now).

[Superdave]

Usually you get quite a few out of them. I've been using some 4mb chips at work for the last 6 years with maybe 1 or 2 out of 400 having problems. They get re-flashed several times a year.

BFUZ is the latest update for the $A1 mask (that we know of).

[Guest]

I just loaded up $88 and BAWX. The initial spark advance is similar to $A1. Leave it alone. It should be 9.84 degrees. I don't even see a value for the spark ref angle, probably since the iron head 3.1's aren't DIS and don't use the 7x crank trigger.

If $88 is like $A1 then those injector constants are just for display, they don't actually do anything. Your global fuel injector adjustments are made to the BPC vs EGR table. I don't know how much the bin i'm looking at has been adjusted so i can't exactly give you the proper numbers to put in there.

I can tell you, if you are running DIS then i'd 100% switch over to $A1 code. I will even help you out with a starter bin. If you really want to stay with $88 then email me your current bin file and i'll have a look at it.

If it's just a stock iron head 3.4 and you just want to get it running i'd put in stock camaro 3.1 injectors and run it on the stock 3.1 tune. There isn't much VE difference between the 2 engines and the computer should handle the fueling just fine.


*Edit.. Chris, the spark ref angle is relative to the 7x timing ring used for DIS. Initial spark advance is pretty much nothing.. it's added to the total but subtracted.. it never shows up in the "SA relative to TDC" logs.

"Spark reference angle" and "Initial spark advance" are the same thing, just called two different names, which is why you can't find what you are looking for in $88. Initial spark advance nor Refernce angle are in ANY logs I have seen, this is a constant that stays the same, and is used fror calculating only, hence why it doesn't need to be spit out the ALDL.

Don't go by what you know of $A1 and say that's how it is in $88, because I'm quite sure that's not how it is.

Wasn't it you that said earlier in this very thread to not arbitrailiy tell someone to do something in the bin?

The initial spark advance should be what ever base timing is set to. So if there was a dizzy installed and the base timing was at 5 degrees BTDC, then that's what initial spark advance should be set to. If the base timing is 10 degrees than initial spark advance should be 10 degrees.

Just an FYI, you may enter a number of "10" degrees, but when the bin is svaed it will usually show up as 9.87 or there abouts, due to the way HEX is saved. the base timing of "59.77" degrees in most DIS bins is what is saved when a value of "60" is entered.

I'll have to fire up my test bench soon and test more code, I need to make an adaptor harness for a '7727 anyway, to do some $59 testing. When I do that I'll try some $88, I'm pretty sure I have some to test.

[Canyonero]

Well hell, my harness swap isn't going in all that well. I could rig up temporary power to see if it will start. But not today, I'm angry enough already.

Couple connectors broke, brittle from age I suppose. Some lengths weren't right despite this being a modified F-Body harness. The different starter location and exhaust are part of the trouble. I'll make it work, just not going to be as easy as I hoped.

[Superdave]

"Spark reference angle" and "Initial spark advance" are the same thing, just called two different names, which is why you can't find what you are looking for in $88. Initial spark advance nor Refernce angle are in ANY logs I have seen, this is a constant that stays the same, and is used fror calculating only, hence why it doesn't need to be spit out the ALDL.

Don't go by what you know of $A1 and say that's how it is in $88, because I'm quite sure that's not how it is.

Wasn't it you that said earlier in this very thread to not arbitrailiy tell someone to do something in the bin?

The initial spark advance should be what ever base timing is set to. So if there was a dizzy installed and the base timing was at 5 degrees BTDC, then that's what initial spark advance should be set to. If the base timing is 10 degrees than initial spark advance should be 10 degrees.

Just an FYI, you may enter a number of "10" degrees, but when the bin is svaed it will usually show up as 9.87 or there abouts, due to the way HEX is saved. the base timing of "59.77" degrees in most DIS bins is what is saved when a value of "60" is entered.

I'll have to fire up my test bench soon and test more code, I need to make an adaptor harness for a '7727 anyway, to do some $59 testing. When I do that I'll try some $88, I'm pretty sure I have some to test.

Spark ref angle wasn't mapped in $A1 till i found it in the bin breakdown. It has nothing to do with initial spark advance. (which is mapped in $A1 and set to 9.xx)

Why the heck would anyone set their initial spark advance to 59.8 degrees in the first place?

we're talking about DIS here, not old Dizzy V8 code

[Guest]

Spark ref angle wasn't mapped in $A1 till i found it in the bin breakdown. It has nothing to do with initial spark advance. (which is mapped in $A1 and set to 9.xx)

Why the heck would anyone set their initial spark advance to 59.8 degrees in the first place?

we're talking about DIS here, not old Dizzy V8 code

Don't believe me, I don't care, but DIS bins use 60* (59.77 in the bin) as initial spark advance.

It's to do with how the reference pulse is calculated.

Here is some info: http://www.diy-efi.org/twiki/bin/view/Gmecm/DISdist

I was using the "10 degrees" as an example.

Just FYI, I've worked with $A1, $59, $6D (a little), $8F (a little), $8D, and tested a few others, so I have seen these relationships.

We are also talking about some dizzy bins as well. $88 is a dizzy bin.

[923.4v6]

I don't know the difference between Initial Spark Advance and the referance, but when I first went to DIS I seen a post somewhere that the Initial Spark Advance needed to be at 59.7 degrees. I tried it at the stock 9.8 but didn't want to start and run right. The only way I got $88 and s-aujp to run DIS was on 59.7 but i'll put one in and try it again to see what will happen. I know from 6 months of run time that it won't hurt the motor.

[Superdave]

Don't believe me, I don't care, but DIS bins use 60* (59.77 in the bin) as initial spark advance.

It's to do with how the reference pulse is calculated.

Here is some info: http://www.diy-efi.org/twiki/bin/view/Gmecm/DISdist

I was using the "10 degrees" as an example.

Just FYI, I've worked with $A1, $59, $6D (a little), $8F (a little), $8D, and tested a few others, so I have seen these relationships.

We are also talking about some dizzy bins as well. $88 is a dizzy bin.

um, load up $A1 with a stock bin and look at the initial spark advance value.. it's 9.14. Then look at the spark ref angle.. it's 59.8 degrees. It's clearly mapped and noted in the $A1 code dissassembly as well.


8013 1A 26 KINITSPK 9 DEG INITIAL SPARK ADVANCE
801B AA 170 KREFANGL 59.8 DEG SPARK REFERENCE ANGLE


I did find the routines where values from both addresses are loaded, it's not noted how each is used to calculate the delivered spark advance though.

[Canyonero]

I just had the crazy thought that it would be easier for me at this point to install all the TBI components and bring this experiment to a close. But where is the fun in that right? I must admit it's pretty tempting.

[Superdave]

lol!

Occasionally Chris and I have these debates..

I guess i don't see why we're arguing, the OP is using DIS and $A1 so all the stock values in the BFUZ bin are fine. Those stock values are running my 3500, hundreds of 3400 swaps and thousands of 2.8's and 3.1's.

It is possible that the "initial advance" term was loosely used in the 80's/90's code. Both values are deffenetly used in BFUZ/ARUR. Spark ref angle (59.8 ) is compared to "Max advance relative to ref (2's comp)" value is -10 degrees.. also "max retard relative to ref" which is -70 degrees.

Initial advance is loaded around AC94 and does something with the value from ACA8. No good notes on how it's handled.