AFR Learn maxing out negative
Hi Guys
Did a firmware update yesterday (thanks Austin) and now i have a very jumping idle, and AFR learn is maxing out negative?
Cam choice 2
Adjusted AFR idle to 13.35 (max vacc + .1)
Temp 181
Idles from 752 to 902 (Target 832)
Pulls 12,8-13,5 HG
IAC 3-5
IAC Learn 1
About my setup.
Olds 403
Fitech 30002 - only fuel control at this point.
10-1 Comp
Edelbrock performer RPM intake.
Edelbrock Alu heads.
XE268 cam
KB Pistons.Dual 2.5" with crossover.
Try cam 1 and see how that works.
Thanks for the reply.
Did play arround for the past couple of days, nothing seemed to work out, so i put the 195 back, and it worked kinda..
Put in 198 and now everything seems to be better, must have been a bug somewhere during the upgrade.
Now i can get it to learn, and start playing all over, did however choose Cam 2, cam one did not work well.
Hello,
I've read what you said about "maxing out negative on AFR learn". I believe I'm doing the same thing. It's hitting the hard stop @ -35.2 during idle. What does that mean?
Quote from GT350 on May 1, 2019, 9:38 pmHello,
I've read what you said about "maxing out negative on AFR learn". I believe I'm doing the same thing. It's hitting the hard stop @ -35.2 during idle. What does that mean?
That the system gives up removing fuel to hit the wanted AFR.
Make sure you have the latest software, made a massive change on mine to go from 195 to 198 (when i get rid of the install bug)
But i am kind of "offline" with the settings right now, due to the weather being to cold to drive the car, but the idle is good (learn values 10-20 ish) and the tipin lean spot i have been trying to get rid of for 3 years, is MUCH better with this software, and it only had one hour of driving time so far, before rain and wind stopped the project for now.
So...it looks like I’m hitting the targets (or close to it), the AFR trim % varies up and down to hit them. I just don’t understand the relationship of the ARF learn % to it.
Having the same issues as you!
1) weather
2) hesitation on throttle snap
I thought the software was only for temperature issues.
Quote from GT350 on May 2, 2019, 10:29 amSo...it looks like I’m hitting the targets (or close to it), the AFR trim % varies up and down to hit them. I just don’t understand the relationship of the ARF learn % to it.
Having the same issues as you!
1) weather
2) hesitation on throttle snap
I thought the software was only for temperature issues.
When you select a cam setting, you are selecting a base VE table. When running the system uses its sensors to adjust the table to hit your target AFR, this is the AFR trim. Then that data is used to adjust the base table, which is the AFR Learn.
For example a 7.4 AFR trim means 7.4% more fuel has been added above the cell in the table. A -13.5 AFR Learn means 13.5% less fuel has been entered into the table for that cell. Ideally after the system has had time to learn your trims should stay within +/-10.
Another thing. There are default limits to fuel learn. Approximately 35%. If your data shows learns this extreme, you may have chosen the wrong cam file.
I see...
I selected cam profile 2. I’m getting about 11-12 hg vacuum @ idle. It’s a SBF 289 .060 over. Edelbrock RPM heads, cam and intake. It’s around 11:1 compression. No timing control. MSD 6A ignition. Using an in-tank walbro 255 pump. Got a solid 58psi @ the throttle body.
Was just trying to tune out a quick throttle hesitation when I stumbled on this forum. Now I’m starting to think I have bigger problems.
So,
if I’m @ a -35 on the AFR learn does that mean all the values in my table are 35% too rich?...or more?
Quote from GT350 on May 2, 2019, 1:23 pmSo,
if I’m @ a -35 on the AFR learn does that mean all the values in my table are 35% too rich?...or more?
Yes.
You can try Cam 1 and reset AFR Learn. Set to 1, send to ECU, turn key off, let ecu power down.
If learn goes too far the other way, there is another way. With cam 2 you can decrease the cubic inch. Effectively fooling the system. Cam 1, you would add cubic inch.