With much credit to 84Elky, i have now switched over to the S_AUJP v6.xdf, in order to perform my $8D editing. As you all know, this definition is highly expanded and well documented. In looking at this table, the description says this:

Fuel is allowed every 6th pass through the ISR (every 37.5ms). A factor is extracted from this Table a maximum of 16 times. Each access progresses through the Table providing:
Access Factor
1 & 2 1.0 (provides 100% of calculated cranking fuel)
3 0.5 (50%)
4 – 8 0.0 (No Fuel)
9 & 10 1.0 (100%)
11 - 16 0.0 (No Fuel)
At 825.0ms +
After 16 passes through this Table without starting (now cranking for 825.0ms), the Extended PW factor Table at 0x3D7 is next used in exactly the same manner as the 16-access 0x3C7 Table which has 8 elements for governing fuel provision:
Access Factor
1 1.0 (100%)
2-4 0.0 (No Fuel)
5 1.0 (100%)
6-8 0.0 (No Fuel)
Once the 8th element has been used and the engine has not started, the Table continues to be used until started.

So, I think i follow it mostly, but i do have some questions. This table of 24 ref pulses really is 2 tables, put back to back. DRPs 1-16 is the initial table, then 17-24 is the extended table. It seems to me that this table should be broken up into 2 seperate tables. So if the code passes thru the first table, 16 times at 37.5mS, how do you arrive at 825mS? I get 600 ms.....

If the engine doesnt start in 16 loops of the first table, it goes to the extended table, and keeps using this 8-element table forever, as long as you continue to crank?
Obviously the multipliers in the table can be anything you want, and 0's give you no fuel at all. I have played with this table over the years, but if you dont really know how the code works, you could be doing more harm than good.

 

BTTT.......anyone? just wanting to know how the code works this table, if im reading it correctly.

 

Mike ---
Apologies. The description of how the table is used was changed in the code comments but was not changed in the XDF. You can cut and paste the text below into the XDF replacing what's there. And yes there are actually 2 back-to-back tables in the code but for simplicity the XDF deals with them as 1 table. Not a problem as long as one knows what's happening, which is hopefully what the following provides:

Revised XDF Description: Table at 0x3C7=Crank PW Multiplier .vs. Ref Pulses 1-24
After the number of MAT-based fuel delay DRPs from the Table at 0x39C have been counted, a value is extracted from this table every DRP thereafter or until the engine starts. This table provides a factor that adjusts the calculated BPW. "Access" below represents 1 DRP which determines the factor used to adjust BPW. After the first 16 elements have been accessed, elements 17-24 will be used in exactly the same manner as the first 16. Once the 24th element has been used and the engine has not started, the process continues, cycling through elements 17-24 until started:
Access....Factor
1,2..........1.0 (provides 100% of calculated cranking fuel)
3.............0.5 (50% fuel)
4-8..........0.0 (No fuel)
9,10........1.0 (100% fuel)
11-16.......0.0 (No fuel)

17............0.8 (80% fuel)
18-20.......0.0 (No fuel)
21............0.8 (80% fuel)
21-24.......0.0 (No Fuel)

 

Hi Elky. No worries. So it looks like you editted this post twice, since you originally posted? The email notice I got last night, has more text in the new description you posted. The above quoted post, appears that you simplified it somewhat, and took out the timing examples?. The original post, i tried to copy paste, into my xdf, but it wouldnt all fit. Must be a character limit in the description box?

So, I think you made the new description clear. Start with the first table, pulses 1-16, however long that takes, and if no start keep going thru the extended table, pulses 17-24, then after no start, just keep looping thru pulses 17-24 forever and ever. No problem, just have to make sure the last 8 pulses multipliers are what you really want to roll with. In my bin, i have no DRP delay via MAT, until 111degF, and there is also another crank fuel PW multiplier table, vs BARO. These values are 1.00 or less, from 105kPa down to 65. I am not sure what the BARO would be during cranking, but this just looks like another multiplier used in the crank fuel PW calculation.

Lastly, in my other bin editor, called TunerCat, using $8D ecm, the definition breaks these 2 tables out, into seperate tables, one for 1-16, and one for >17. Just a fun fact for you! Good stuff here!
Mike

 

Yes, original description too long for XDF so edited. Can run various cranking delay/duration calculations knowing that 400 RPM = 1 DRP every 37.5ms.
BARO at sea level 101.4 kPa = barometric pressure = 29.92 InHg

 

OK, cool. I had made a calculation in my notes, of cranking at 450rpm, which equals 30 pulses/sec, or 33.3 mS/DRP. As you know, crank speed depends on a lot of things.....
So the BARO table is just an extra multiplier, based on atmospheric pressure. I did some calculations, and so if you are less than 31 inHg, then the multiplier will be used, likely between 95 and 105 kPa. Must be this if for if your engine is at high altitudes.....

 

Yes the table you reference is used in the cranking PW calculation. But don't confuse the issues. The discussion in this thread has been addressing cranking PW delay and when the calculated cranking fuel will be provided.

Calculation of the cranking fuel to be provided is another issue and don't understand the reference to "high altitude . . .". The Table at 0x3FD=Cranking Fuel Multiplier .vs. BARO provides factors used to adjust the calculated cranking PW based on barometric pressure from approximately 1000 ft below sea level (105 kPa) to approx 12000 ft (65 kPa).