whittlebeast wrote:
In the trace you posted, there is way too much AE and you are most likely putting out the fire with all the fuel. The spike in the AFR is the result of the fire going out.
Plotting PW on top of MAP will generally show the same pattern.
Hope this helps
Andy
That may be true when I am actually using AE as in getting on it. The problem I am having is not during AE. This is between closed throttle and like 5% throttle give or take. I have already corrected AE based on Matt's suggestion but didn't replace the log before the change because this is a low loads, not when I am trying to accelerate. I have attached a new log and tune though that might help focus attention on the issue I am having. That said (and this log and tune do not reflect the changes) I have made some suggested changes. I lowered the VE table in the suspect areas and made some adjustments to timing to hopefully eliminate the lean popping I get at low load/High AFR. I have not run the changes yet but I am about to.
Also I will try creating that new field you mentioned since it would probably be beneficial for future tuning. Thanks!
Matt Cramer wrote:Try adjusting the VE table at the point where it's too rich.
Done but didn't help. If I am cruising in those bins I am getting 14.5 AFR. But when I crack the throttle 3-5% it still drops like a rock. FYI, this doesn't happen at idle at all. Also I made sure AE is off just to remove that as a possible issue. I could drop the fuel bins even more but I get a lot of lean popping at low loads. As suggested by someone else, I lowered timing in those areas which helped but only a little and its making the car feel a bit lethargic. So I don't want to go any lower with timing. Any other ideas?
Does your last post and the description of the behavior come from the msq/msl you posted one post up?
I'm by all means no expert, but occasionally I sign on to msextra on a reasonably big widescreen desktop computer (vice my 10" tuning laptop) and get tempted to poke around other people's logs/msqs, plus I'm d*** tired of shoveling snow. Feel free to take what I say with a grain of salt.
1. Your injectors are very big, and driving them at 4 squirts/simultaneous is forcing them into the sub 1ms to 1.4ms range. Most advice I've seen on this site indicates that you should try to stick out of the non-linear injector zone (safely 2.0ms or higher). Looks like you are throttle body injected based on 2 injectors in your msq, so I'm not sure what is better for you (sticking to over 2.0 ms fuel injection duration and less squirts, or more squirts/even fuel distribution to your cylinders but less than optimal injector duration). For instance, you are idling at 11.6 AFR at a PW of only 1.17ms.
2. Based on log entry at 80.559, you should remove quite a bit of fuel from your first two rpm columns (and likely more).
Thanks for the reply! Yes, the log and tune would be the most current based on my recent description.
It's funny you say my injectors are very large. In other posts they were to small which is when I raised fuel pressure from 13 psi to 43 psi to compensate. The reason was due to higher than 100% duty cycle in the logs. That proved to be to high as I was no longer able to lean out idle. It stayed rich no matter what I adjusted the bins to so I lowered the fuel pressure down to a more manageable 30 psi. I occasionally see duty cycle near 90% now. Yes, it is TBI for now. The reason I am at 4 squirts/simultaneous is to help prevent lean popping at anything below 30% load. That said, I don't think it's helping anymore. I have been idling at about 12 AFR just because the car seems to like a really rich idle. So I might go back to 4/alternating.
dragbug wrote:It's funny you say my injectors are very large. In other posts they were to small which is when I raised fuel pressure from 13 psi to 43 psi to compensate.
I may have jumped the gun on calling them very big based on my experience in port injection (and inexperience in tb injection)and the pulsewidths you were requesting per your log. Doing some quick math they appear to be similarly matched in total fuel delivery to my stock injectors on a port setup (per cylinder anyways). The commanded pw in the log seems pretty low, so you may find some benefits in allowing some longer pw (by reducing squirts per cycle or switching to alternating)