Diablosport Forums

Can someone explain the difference between the PID, Desired FA Cyl 1 (AFR) and the reading I get on my AEM Wideband guage during WOT? The Desired FA is a constant value (Straight line) when my AFR's are reading 12.5 (Straight line) and everything is good. When I get to 5500 rpms and above, the Desired FA takes a nose dive down in value and my AFR shoots to the ceiling from 12.5 gradually getting higher than 14.0. TKS for any assistance ahead of time.

your afr on the WB goes from 12.5:1 to 14:1 at WOT above 5500 rpm?

the dip in commanded fueling is likely COT kicking in, but it should get richer there...

My last run today, shows the following (No short or long term knock):

4400 rpms Desired AF: 12.29, AFR Sensor: 11.17
4800 rpms Desired AF: 12.2, AFR Sensor: 11.15
5400 rpms Desired AF: 11.12, AFR Sensor: 12.37
5700 rpms Desired AF: 11.12, AFR Sensor: 13.23
5800 rpms Desired AF: 11.12, AFR Sensor: 14.15

These are the values with a supercharger just installed. The same thing happened on my run just before the SC install but the values were in the 12's then the Desired took a dive like above and the Sensor reading shot up to the 14's. And again not any short term knock when I was NA a few days ago.

I also installed 52 lb injectors and the 392 fuel pump with the blower. (5.7L Hemi with Edelbrock)

if you are confident the WB is reporting properly you need to sort this out, check pressure, have the tune looked over, etc.

Thanks, Dyno today to put sniffer on the tailpipe.

I don't understand why the A/F is going lean? Is it possible the fuel filter is clogged?

The desired readings are pretty close to what mine is doing (turbo, not supercharged), fattening at higher rpms

3500rpm - 14:1
4000 - 14:1
4500 - 14.2:1
5000 - 13.7:1
5500 - 13.6:1
6000 - 12.9:1
6500 - 13.2:1
5100 - 20.5:1 (shift)

Just found out today on the dyno the AFR guage is fine. The injector pulse width is going lower when the AFR's are going up. The tuner at the shop says everything is fine with the fuel system and injectors but that the tune needs to be corrected above the 5500 rpm range where the injector pulse width decreases with higher rpms. Dyno'd 503 rwhp at 5000 rpms when we stopped to get the tune adjustments. Should be fixed over the weekend. He said it was an easy fix for the tuner once he saw the data. This Edelbrock also put down 520 lb-ft torque. Modern Muscle SC Cam/Heads/ARH LongTubes were worth the $$$. Just 6.5 lbs boost

id check to make sure its holding fuel pressure up top.