LSJ Tuning Woes
- Thread starter Ghostknife
- Start date
A few specific questions here:
#1, I'm going to try to log misfires. In the scanner, I see multiple parameters for misfires....I have selected "total misfires". Is that the right one?
#2, My LTFT seems to be weird. My wide band is behaving correctly....I can see positive and negative values:
But LTFT is ALL NEGATIVE. It's just pulling fuel all the time, while I can clearly see (and feel while driving) that it's way lean. Is there something wrong with the stock scanning software? That LTFT parameter was one of the stock options, I didn't do any crazy math or anything to log it.
#3....this thing was really dialed in great at about 95 degrees F. I was plus or minus about 5% on my fueling all the time. Now that it's 75 degrees, it's generally pretty lean. To me, that means either: 1, the ECU is failing to account for temperature, or 2, it's accounting for temp but my injector flow tables are wrong, so it's not throwing enough extra fuel in even when it tries. Does anyone have 60# injectors that would care to share their flow rates?
Finally, #4...my injector duty cycle % is just blank all the time. What is the correct parameter to log that?
log file attached,though I doubt it's useful since half the logged parameters aren't working, and the other half are the wrong ones.
#1, I'm going to try to log misfires. In the scanner, I see multiple parameters for misfires....I have selected "total misfires". Is that the right one?
#2, My LTFT seems to be weird. My wide band is behaving correctly....I can see positive and negative values:
But LTFT is ALL NEGATIVE. It's just pulling fuel all the time, while I can clearly see (and feel while driving) that it's way lean. Is there something wrong with the stock scanning software? That LTFT parameter was one of the stock options, I didn't do any crazy math or anything to log it.
#3....this thing was really dialed in great at about 95 degrees F. I was plus or minus about 5% on my fueling all the time. Now that it's 75 degrees, it's generally pretty lean. To me, that means either: 1, the ECU is failing to account for temperature, or 2, it's accounting for temp but my injector flow tables are wrong, so it's not throwing enough extra fuel in even when it tries. Does anyone have 60# injectors that would care to share their flow rates?
Finally, #4...my injector duty cycle % is just blank all the time. What is the correct parameter to log that?
log file attached,though I doubt it's useful since half the logged parameters aren't working, and the other half are the wrong ones.
#1: I would look at individual real-time cylinder misfires if it's available, if not maybe the individual sums. A general misfire in all cylinders could be tune related. If just confined to 1 cylinder it's more than likely a different problem.
#3: Injector data is more than than just flow rates.
#4: You may have to log injector pulse in ms and do some math to get duty cycle. And if a channel isn't logging in the list, it won't show up in the graphs or charts.
I don't know enough about the lsj to know if you have everything set up right to tune, but you aren't up to operating temp in the screen shots. What are you using as guide for tuning? Be careful of using a guide or video for an LS V8 ECM since each of the ECM have their own peculiarities that might need to be set up for.
#3: Injector data is more than than just flow rates.
#4: You may have to log injector pulse in ms and do some math to get duty cycle. And if a channel isn't logging in the list, it won't show up in the graphs or charts.
I don't know enough about the lsj to know if you have everything set up right to tune, but you aren't up to operating temp in the screen shots. What are you using as guide for tuning? Be careful of using a guide or video for an LS V8 ECM since each of the ECM have their own peculiarities that might need to be set up for.
Rauq
Goblin Guru
Agreed with each of the above points.
#1 log each of the 4 cylinder misfires
#2 I don't tend to use WB data unless I'm in an OL tune or I'm filtering to see only PE (commanded AFR <14.7)
#3 I don't have 60# injector data, you could find other people's tunes to compare or ask whoever you got your injectors from
#4 almost certainly you're missing a channel, probably injector pulse width. I don't have HPT up right now but I think if you go into the Maths menu you can look at the preconfigured/custom channels and if you look at Duty Cycle it might show red for channels not currently configured to log?
Post up if any of the above or other points require clarification.
#1 log each of the 4 cylinder misfires
#2 I don't tend to use WB data unless I'm in an OL tune or I'm filtering to see only PE (commanded AFR <14.7)
#3 I don't have 60# injector data, you could find other people's tunes to compare or ask whoever you got your injectors from
#4 almost certainly you're missing a channel, probably injector pulse width. I don't have HPT up right now but I think if you go into the Maths menu you can look at the preconfigured/custom channels and if you look at Duty Cycle it might show red for channels not currently configured to log?
Post up if any of the above or other points require clarification.
baustin
Well-Known Member
I need to read more into what's happening to Chubbs' build this weekend. His build seems very similar to mine except I have a 2.9" pulley, I do have 60# injectors. I didn't do my own tuning, I had ZZP remote tune it. But my log setup I have saved somewhere might be helpful for the logging issues, that and I can compare my tune. I don't recall how different an '07 LSJ should be from the '06 LSJ I have.
He definitely needs to find a good scanner set up. There should be some in the GM L4, I5, I6 HP Tuners forum.
GM L4, I5, I6 Tuning - Engine (hptuners.com)
GM L4, I5, I6 Tuning - Engine (hptuners.com)
Thanks everyone for the help.
Driving home from work yesterday (about 20 minutes) it just got leaner and leaner throughout the drive. By the time I got home, it was spitting and sputtering at 17:1 AFR. No bueno.
I did a little research on my always-negative LTFT. There are reports of others having the same issue after getting a mail-order tune, but no solutions. I think somewhere along the way I adjusted something I should not have adjusted. I thought it was a software bug, but after watching my AFR get leaner and leaner consistently, it's obviously producing real-world results that aren't good.
So, I'm going to take a few steps back and start over with a known good tune (maybe even bone stock). Ghostknife's is tempting, but if I remember the thread right, his was tuned a bit before he built the goblin and tuned it further. I'll regroup and report back.
Driving home from work yesterday (about 20 minutes) it just got leaner and leaner throughout the drive. By the time I got home, it was spitting and sputtering at 17:1 AFR. No bueno.
I did a little research on my always-negative LTFT. There are reports of others having the same issue after getting a mail-order tune, but no solutions. I think somewhere along the way I adjusted something I should not have adjusted. I thought it was a software bug, but after watching my AFR get leaner and leaner consistently, it's obviously producing real-world results that aren't good.
So, I'm going to take a few steps back and start over with a known good tune (maybe even bone stock). Ghostknife's is tempting, but if I remember the thread right, his was tuned a bit before he built the goblin and tuned it further. I'll regroup and report back.
I have to ask how sure are you about your tuning knowledge? I’m sure that you aren’t logging enough channels to really tell what is going on. And at least on some of the GM V8 stuff you don’t want to be using closed loop if you are tuning with the wideband (if you are). The LT seem to follow the ST. I think maybe you are doing something wrong that is driving things further to being wrong as you make changes. I wish I knew more about the LSJ to say what you might be doing wrong and I could be totally off base.
I'm not.
On it's surface, it's easy. Set up a log table for AFR from your wide band sensor (done). drive and log. Then modify your fuel tables to compensate for how far off your AFR is. Repeat over and over, and get a perfect tune! Obviously I skipped a whole bunch of details in there, but that's about it.
But, then we get into issues where weird things happen. It's perfect one day and not the next. It runs great for half an hour, then it doesn't for 30 seconds as the o2 sensors fault for some reason. Maybe there is a big problem area in the timing curve where a bunch of knock-retard is happening.
I was able to get the car running 80% in about an afternoon. The final 20% has taken me a year to dial in, and as you can see in this thread, I'm still not there. That last 20% is hard.
It’s all of the details that make a difference. I would think on the lsj that it is similar to the LS stuff where you have to tune the maf and VE tables separately and have to fail certain things to make that happen. Have you tried tuning it with the narrow bands in the cruise rpm? And again I think it likely needs to be in closed loop to use the wideband to tune.
As far as knock retard, you need to monitor it along with timing and misfire and narrow band o2 voltage, and probably a dozen more.
Are your injectors from ZZP or somewhere else that supplies full GM format data, and not just flow rate!
As far as knock retard, you need to monitor it along with timing and misfire and narrow band o2 voltage, and probably a dozen more.
Are your injectors from ZZP or somewhere else that supplies full GM format data, and not just flow rate!
Keckster
Well-Known Member
I'm running into some similar issues with the car randomly having similar issues. My donor was originally an 06 but swapped to and 07 PCM due to the supercharger bypass circuit being bad in the 06 pcm. I was fighting these issues until i recently came across this thread removed rear O2 car goen into open loop randomly. I the thread they talk about how this is a apparently known issue with the 07 pcm in the community. I swapped back to my old pcm and although i got no boost cause of the original supercharger bypass solenoid issue, all my other random lean/ open loop activation issues were resolved.
ctuinstra
Goblin Guru
Here is 1-hour drive log of mine that shows it also goes into OL periodically. I always assumed this was for a test, most likely the second O2, but now it sounds like it's pretty proof positive. I never worried about it because it didn't seem to cause any drivability issues. The UP/Down spike you see in the middle was the only time is was in plain OL. The commanded jumped up to 16.20 and then dropped to 12.90. All of the other little dips you see are OL-Accel/Decel and are most likely because of PE or other commanded AFR based upon the accel or decel and not a test.
I should turn on the P0136 (O2 Circuit Bank1, Sensor 2) to see if it logs a DTC after the change in the commanded AFR. Not that this would stop it from happening, but just to prove that's what is going on.
I should turn on the P0136 (O2 Circuit Bank1, Sensor 2) to see if it logs a DTC after the change in the commanded AFR. Not that this would stop it from happening, but just to prove that's what is going on.