EFI Live and Pilot Quantity Lookup

EPA Violator said:
Hey Biggy, good work, I'm currently tuning my truck with the help of a friend and experiencing the same growing pains you are. I've found that to get idle right you have to do what you're doing and come at it backwards. EFI didn't map out the idle fueling. I'm doing an 08, CM2100 which is little different.
Click to expand...
Thank you, hope it helps someone. I'm planning to leave that change on tune 1 only and then just smirk when it lopes on the 'big tunes'

Sent from my motorola one 5G using Tapatalk
 
95cummins5.9 said:
Is there any adaptive learning with a factory ecm? What year ecm are you fiddling with? I know nothing, but interesting in learning.
Click to expand...

biggy238 said:
No adaptive that I am aware of. This is a CM849A or B. I honestly dont remember.

It sucks to try and learn in post EPA apocalypse because a lot of the knowledgable users either ghosted or are afraid to help out or got gag orders from the supreme overlords.
Click to expand...

There is 0 adaption with the CM849.
 
biggy238 said:
For the visual learners in the crowd.

View attachment 77742
This log shows the corrected idle. Interestingly, you can only see blips in the RPM now when it's shifted into gear.

View attachment 77743

The old map showing the duration causing the overfuel. The issue is the same as a mechanical governor bouncing, either too much fuel or not enough, so it's bouncing between the two to try and maintain median RPM. You can see this zoomed in on the log, by the time the RPM overshoots, the PID had already cut fuel by 200uS. RPM on the up slope, fuel on the down slope. This causes an undershoot and the PID tries to recover/correct via adding fuel by selecting the cell it thinks will save it. The issue is that because the injectors are oversized, the injection event causes an overshoot of rpm and the loop repeats.
This is how a Lope Tune works if you are doing this intentionally. I'm not a cool kid though. I am leaving the lope in tunes 2-5 though just to be a dick.

View attachment 77745

New map showing where I inserted the amount of fuel I knew it needed based on the logs I had taken.
Click to expand...

Getting idle straight with oversized injectors is often times a betch. I have not had much luck using the injector flow sheets for this area of engine operation.

With idle there are three things that "matter":
- Idle speed and overall load
- Stability
- Smoke

I have not had an unstable idle like what you experienced (at least not yet anyways, I may just lucky with my tactics).

For speed and load work, I disable all temp scaling factors. I do this so the engine does what I want it to.

For smoke control at idle, injector on time can be reduced, timing added and rail increased. At least that's how I do it.
 
RD TRCTR said:
Getting idle straight with oversized injectors is often times a betch. I have not had much luck using the injector flow sheets for this area of engine operation.



With idle there are three things that "matter":

- Idle speed and overall load

- Stability

- Smoke



I have not had an unstable idle like what you experienced (at least not yet anyways, I may just lucky with my tactics).



For speed and load work, I disable all temp scaling factors. I do this so the engine does what I want it to.



For smoke control at idle, injector on time can be reduced, timing added and rail increased. At least that's how I do it.
Click to expand...
Thanks for the hints.

It would be a piece of cake if the PID for Zero Throttle (idle) was exposed, but you see what I did as a work around. The good thing was that I didn't have any driving issues from the change I made.

I tried to utilize the flow sheet (I was smarter than Me because I knew I would lose the sheet and I took a picture of it) but without more data points, I can't build a model/spreadsheet to cross flow Vs Pressure and duration.




Sent from my motorola one 5G using Tapatalk
 
You must log in or register to reply here.
Back
Top