I have searched and have not been able to find what I am experiencing. When I first start my car and begin to drive with coolant temps around 30-50C, I get a lot of spark retard. Once the car reaches 70-80C all spark retard disappears. Full throttle, part throttle, idle.
Is there a table that adds spark to a cold motor to help warm it up quicker? If I am not mistaken there is one in $6E, as I had the same issue and was able to zero it out.
I am currently using $8D. Thanks

 

 

Thanks! Do you have the hack for $8D? What is the value at 8137?

 

The hac is on the diy-efi.org site. The value at 8137 is the bias for the table.

RBob.

 

I was not able to find the hac? Do you know what directory it is within?

 

look at 0x1B9 on your $8D xdf

 

At what point in the routine does it stop using that table to add spark? Once the ecm enters closed loop? Time delay?

 

Direct link:

http://www.diy-efi.org/gmecm/papers/anht_hac.pdf

It is on this page:

http://www.diy-efi.org/gmecm/papers

RBob.

 

Thank you.

 

Why not refer him to an updated hac?
There are known problems that have been updated.

http://www.gearhead-efi.com/gearhead...20and%20Hacks/

Look for AUJP_JP2.zip

 

Then you should have spoke up sooner. I pointed the OP to the original hac. Not knowing that there is an updated hac that also may not or may be correct exists.

Yes, there are some errors in the original hac's, but they are better then nothing. I actually told that to someone that didn't like the ambiguities in my $61 hac. Flat out stated that if you don't like it, then do your own hac...

RBob.

 

Thanks.
Looking at the hac, I cannot seem to understand how idle spark is calculated. My car will idle at 700-750rpm at op. temp, but in my logs the SA jumps all over the place. Looking at the tables none of the values make any sense. Can you run me through how idle spark advance is calc?

 

possibly relevant, but assuming you remove the coolant temp dependant SA and still see KR, i've been in a few situations where even a slight misfire was being detected as knock. what would cause that at lower coolant temps and goes away at higher temps, i couldn't say, but just something to keep in mind.

 

Yup,
For anyone to spend the time it takes to even get close to detailing code, there are always be ommissions due to time or errors that "hopefully" the next guy will help adding detail to.
And for those that complain after they spent two hours looking over something you've worked on for a year and find an error...
I'm glad to see there are still some people who have taken the time to go over existing works and make them better.
Thanks to those who try and share.
Jp

 

Likely you are seeing the idle compensation SA. This is where the SA is raised and lowered to help with a smooth idle RPM.

IIRC, $8D has a closed throttle SA table. So that will be used, then compensated for the idle RPM. Too high and the SA is decreased, too low and the SA is increased. Basically using torque control to smooth and prevent a rolling idle speed.

RBob.

 

What I don't understand is why these "improvements" are being posted elsewhere. When after the DIY-EFI board fell apart (thanks to steve ravet), TGO become the focus of the best in this area...

RBob.

 

There is actually a single constant on 8D code that disables spark advance other than base timing until you reach about 120*F coolant temps. Its part of the air injection system to warm up the cat. Once you disable this, the timing will be normal. My old G20 Van running 8D on cold mornings would run sluggish for about 1/2 mile up my street. There was a traffic light at the end of my street before jumping on the main road. Well it would ALWAYS jump to life at that light, the idle would jump up several hundred rpm, and it would almost push me out onto the road. Took me a few hours digging though the hack to figure that one out.

 

I lowered the value at L$031 from 40C to 20C and that helped.
I played around with the idle SA adv and retard last night by lowering the values in the first few cells. At idle the rpm would hunt a bit, but the biggest difference that I noticed was that when in gear and slowly accelerated the car did not jump forward. Prior to changing those values the car would feel sluggish and then jump forward.

Fast355 - Do you recall where that constant is or what it is called?