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Hello everyone,
Got my injectors installed and my tune flashed for the larger injectors but it seems I didn't adjust a table correctly as my trims jump around a good bit but usually hang around -17. Any recommendations on where to look?
It's impossible to tell anything with just a screenshot and not an actual log.
It's also impossible to tell anything with out...well what the hell you are working on, what the mods are, what PCM you are using and a tune file would be nice.
But based off that screen shot, there is something going on with bank 1.
I thought i had attached my tune as well as the screen shot, my apologies. I'll grab a log tommorow, but my logger tends to have large gaps between datapoints so it isn't as helpful as I would like. It's a fully stock LM7 with a flex conversion. Stock P59 PCM, just using lsdroid to flash. I've attached the tune, primarily just been messing with the transmission shift parameters to fix a slow 1-2 shift, and to compensate for larger tires. Fuel wise the only thing I've changed was based off of a stock L59 tune, I just copied the injector parameters. Waiting on my wideband but even with it being negative it smells fat at idle. I've noticed that at wide open it tends to move closer to zero, but I was under the assumption that changing the injector characteristics and flow rate would keep the fuel Trims close to zero without needing to mess with the VE table. Bank 1 has 1 or 2 clogged injectors, tried cleaning them out with carb cleaner and it improved a bit but still has higher trims, I have a new set of injectors just waiting on it to stop raining.
I thought i had attached my tune as well as the screen shot, my apologies. I'll grab a log tommorow, but my logger tends to have large gaps between datapoints so it isn't as helpful as I would like. It's a fully stock LM7 with a flex conversion. Stock P59 PCM, just using lsdroid to flash. I've attached the tune, primarily just been messing with the transmission shift parameters to fix a slow 1-2 shift, and to compensate for larger tires. Fuel wise the only thing I've changed was based off of a stock L59 tune, I just copied the injector parameters. Waiting on my wideband but even with it being negative it smells fat at idle. I've noticed that at wide open it tends to move closer to zero, but I was under the assumption that changing the injector characteristics and flow rate would keep the fuel Trims close to zero without needing to mess with the VE table. Bank 1 has 1 or 2 clogged injectors, tried cleaning them out with carb cleaner and it improved a bit but still has higher trims, I have a new set of injectors just waiting on it to stop raining.
At least your LTFT values are not maxed out at 25 at any point in that log. In other words, your STFT numbers are still able to keep the LTFT in control and not maxed out. You were nearly at normal at 623 seconds into the log.
Figured I would update this thread.
There is a video out on the web where it is said that your fuel flow table can be set to 4.16 across the board. This is NOT the case, against my better judgement I trusted the video, I ended up going to the stock map and multiplying my fuel flow by 1.0 + whatever my fuel trims were converted to a decimal. For example, 1.18 for what I was seeing. I ended up doing this 3 separate times after logging a test drive. The only cell that should be 4.16 for the flex injectors is the 0 KPA cell. My fuel trims are finally normal, at 1.7% average on the long terms.
Well I finally got my injectors in and that helped a good deal with getting the banks balanced, I'm still at -3.5% both banks but that's an easy fix. My larger concern is I'm now stuck open loop for the most part, it goes closed loop randomly. Only change is fresh injectors and I now have a misfire on cyl 2 as well but I think that's just a pinched oring (brake clean test made it stumble). Been doing some digging online and cant find a definitive answer on if a misfire will force open loop, I'm currently logging my misfire history for all cylinders so I can see when it happens and the fuel system status and O2 volts but other than that I dont know what would cause it to stay open loop and go closed loop randomly.
If it's going closed loop randomly I would look at what's required to get closed loop, so a minimum coolant temp, and whatever else is currently escaping my mind.
I do not believe a misfire will cause open loop.
Coolant temp was at 192*, it now spends more time closed loop then previous, but when it is open loop its almost like the throttle body gets stuck. On decel, rpm will only drop to jsut under 1k and you can feel the engine maintain speed. Only thing I did was clean my throttle body when I put the new injectors in, but thats when it all started? Could it be the PCM trying to do a throttle body relearn that's keeping it open loop? Can't drive the truck since a lower ball joint is worn more than I am comfortable to drive with it anymore, hope to be back at it Sunday though.
12-11-2019, 08:21 PM
Negative Long Term Fuel Trims on Flex LM7 
