Thank you for the reply KitchOriginally Posted by Kitch
If resetting using the battery disconnect will work it would really make make day. I attempted clearing the codes using the scanner but it didn't even blink. it stayed set unlike the previous Code 42's I cleared that were set when by disconnecting the EST wire.
Update
Pulling the battery power reset the computer and all is good in the world again. Thank you for the gimme. I'm still new at this EST thing as you can tell I'm sure.
The Mask I am using displays the Mask ID in hex so it is not required to specify the $ before the AA. I am sure I had the checksum disabled.
That being said, I had some issues getting Emulation/Logging working this morning. It would say it was communicating but it did not actually work. I got to tinkering and found an option to 'Initialize Emulation Hardware' I clicked it and sure enough the Logging started working. I had some stuff to do today so I opted to just log and not emulate but I feel reasonably confident it too will work now. Not sure if that had anything to do with the malfunction yesterday or not. I am thinking it would not run at all while the emulator is plugged in if it wasn't actively passing information.????
I made some headway with the bog/dying I was experiencing. I noticed I had an advance timing value of 23k+ when the bog was happening. I remembered reading about it previously so I went back and found http://www.gearhead-efi.com/Fuel-Inj...-Advance/page2 from Dec 2019 started by Jimmie. As a result, I zero'd the Main spark Bias and the Altitude Spark Bias. Made quite a difference. I could actually get off the line without it dying on me although the bog was still evident. Next I turned the Injector lb/hr value down to 64 lb/hr from 84 lb/hr. Still bogs slightly initiating hard throttle from a stop but man - it really woke up.
So here's the deal I am wondering about now. Obviously I need more fuel and we can get there from here with either higher pressure or bigger injectors or both. I am good with this.
Question is WTH does this thing WANT to pull a crap-ton of timing coming off idle? This has me stumped. I don't like the idea of leaving the spark Bias at ZERO as it gets pretty warm here in the summer and I have no doubt it will make a difference on the tune when it warms back up. I am concerned detonation weather is around the corner and I rather like the option of going negative to save the engine when it's hot. I have a feeling the timing will be high across the board at this point since I just removed the Bias values. I will capture that in the next session
Is the timing issue related to the MAP increase on sudden throttle? That's where I will be looking next. I don't to mask the root cause with removing the Spark Bias.
As always, appreciate any input.
Don't play with the bias values. Set those to stock and leave them alone. All you are doing is manipulating the timing value with the wrong values. The 23K reading is the result of a negative timing value. You need to increase the spark map on that area to get the timing advance positive again. With Vortec heads I almost never have any value in the timing table under about 8 or 10°.
Copy that. I really had no intention of leaving it this way. I see the removal of the Spark Bias as a troubleshooting step not a permanent fix. I believe I have identified I need better fuel mapping and better spark mapping at this point. It did help e to clearly identify I need more fuel. Initially I wasn't sure due to the negative timing hitting at the same time.
I just finished reading this post where Dave w had a similar issue. http://www.gearhead-efi.com/Fuel-Inj...ED-sorta/page2
Not sure what came of it but Dave w linked his issue(s) to the Altitude Spark Bias. Here is a link to the service bulletin referred to in the post by 1project2many also http://ww2.justanswer.com/uploads/he...gine_knock.pdf
I did not try removing the Altitude Spark Bias first. I just yanked them both. I will put the Standard Bias back in first as a test. If nothing else, I can capture a range of what the timing would look like to provide the same performance as a baseline for working the spark map. It seems counter intuitive to add enough Spark to counter act the Spark Bias though. I would feel a lot better if I could quantify why this thing WANTS to pull so much timing out to begin with. I guess that's what bothers me the most at the moment.
I will use your numbers as the lower limit reference now to give me an idea where I am during the process as I try to learn what this engine wants. Really appreciate your input sir.
I will leave the fuel alone and put the Spark Bias back in. Maybe it just wants the fuel?
Thanks again
OKay Fast 355.
I am better understanding the spark timing scheme now and your comment about raising the tables in that area are jiving now.
If I am wrong here, please correct me.
The main spark Bias is always subtracted in the timing calculation. I was not understanding that initially. I was thinking it is only applied under certain circumstances. In fact, it is always used and the effect shifts depending on the spark table it is looking at. This way it is not required to have many spark bias' set up to handle the varying conditions.
Anyway, question now is, WHEN does the Altitude Spark Bias come into play? I put the Main Spark Bias back into the program without negative effect but I have not put the Altitude Spark bias in yet. Is there a specific table it is associated with in $OD?
I am glad I pulled the Bias' out because it quantified a problem and even gladder I didn't melt anything.Maybe not the best plan I ever had.
Thanks,
Jeremy
A bias value is used so that you can have a negative value in the table. I would have to dig up the whole hac but I am certain from memory there is a baro correction of the spark advance in the calibration. That would be where the altitude spark bias comes up. The higher in altitude you get the lower your baro kpa. Also keep in mind that reported spark advance from the datastream will be innacurate if the initial or base timing is any value other than zero. On my definition I had to alter the equation to add the 10° initial back into the calculation. Otherwise it reported the timing 10° lower than actual. Add the altitude bias back in and ignore changing any bias values. They are all used, otherwise they would not have a valie other than zero. When I added IAT compensation in, I had to add a 10° bias to allow the IAT table to retard the timing in hot weather.OKay Fast 355.
I am better understanding the spark timing scheme now and your comment about raising the tables in that area are jiving now.
If I am wrong here, please correct me.
The main spark Bias is always subtracted in the timing calculation. I was not understanding that initially. I was thinking it is only applied under certain circumstances. In fact, it is always used and the effect shifts depending on the spark table it is looking at. This way it is not required to have many spark bias' set up to handle the varying conditions.
Anyway, question now is, WHEN does the Altitude Spark Bias come into play? I put the Main Spark Bias back into the program without negative effect but I have not put the Altitude Spark bias in yet. Is there a specific table it is associated with in $OD?
I am glad I pulled the Bias' out because it quantified a problem and even gladder I didn't melt anything.
Thanks,
Jeremy
Last edited by Fast355; 11-19-2020 at 01:21 AM.
Thank you for the reply Fast355
I recognize you are a VAN guy and this is a half-VAN [pick-up]. JI recall the times my friend and I frequented the street races in Dallas with his Dodge conversion van. We didn't win EVERY race but it was a great feeling when he would smoke a Camaro in the big orange early 70's 'hippy mobile' with the Sierra Nevada mural on the side. Surprised a lot of people for sure. I can appreciate why you enjoy hot rodding your vans.
Copy that. I understand a 'bias' value is substracted from the Main Spark Table and allows for negative timing. I am trying to get my head wrapped around when the engine transitions from one spark table to the next and how the program prioritizes which table to read from. Unfortunately, my brain doesn't comprehend hex well enough follow the path of operations in the background. I still have a lot to learn it so I appreciate the input.
I am dialed in at the distributor [base] 10 degrees and have set the Initial Timing for 10 degrees in the XDF. I have also changed the ADX to accommodate the 10degree initial timing. I did notice the data stream appears to be reading total applied timing rather than commanded timing. Does the Main Spark Table then show the total Commanded timing prior to any bias being applied?? I think this is correct?
Anyhow. I can add/take away the altitude bias and it will do pretty good when it's removed but dies on tip-in when I put it back in. I feel like it is just masking the issue I need to adjust as you have eluded to as well.
Fuel. It seems like a fuel issue. Still. Ie. TPS increases suddenly, Map [kPa] increases and the timing nose-dives below zero . If it had fuel, the MAP wouldn't transition [ramp rate] as quickly allowing the timing to keep-up by not calling for the BIAS to prevent knock or whatever. Am I off my rocker here?
That being said, I went in and added 5 degrees to all the areas shown as 'negative' with no real performance gains with the Altitude bias @ 9.8. I also increased AE vs MAP by 60%. No real gains while Alt Bias was @ 9.8 but it did run a bit better on tip-in when the bias was zeroed.
I found the Altitude Spark Advance Correction vs BARO vs Vacuum I think you are referring to. Also Baro Correction Factor vs RPM vs TPS. This is where I start to get befuddled.
First, there is box to choose BARO and MAP being used together or NOT. Currently this box is NOT checked. Does it need to be? Seems like it should be but it is listed as a transmission parameter.
Second, do the two tables listed above add or subtract timing? Looks like the Alt Spk Adv Corr vs BARO vs Vacuum subtracts and the other adds?
Third, I am confused about this equation: .351563 * (X-Y). If X is Main Spark Table [commanded] timing and Y is the Bias how does this make negative timing?
Seems like it would be (.351563 * X)-Y ??? I must be missing something.
As I continue to research, I appreciate any help as always.
Jeremy
Posting Permissions
Reply With Quote
Bookmarks