AEM Ultimate Resource Thread>>>>

[slava]

I wondering if anybody has an explanation for my o2 buble.
Idle and low cruse front o2sensor is leaner and full throttle rear is leaner but only between 5.5-7k.
O2 feedback is turned off.
PC Log


Same run Internal log

[defgh1]

Originally Posted by slava

Anybody run dual WB? are the reading the same all the time?

I have dual wide bands, dual fuel feed setup and hot wired supra pump and have almost a 1 A/F ratio difference between front and rear bank at idle and low boost. At higher boost and WOT they are the same.

Doug H

[slava]

I am wondering if different wb readings has something to do with back presure or...
maybe i should put both o2sensor in one bank and see if they are reading the same or not first.
Since lean condition 5.5-7k does not produce much knock i suspect that o2 readings might not be correct.
any ideas?

[HydeDW]

I am pursuing reason for my lean O2 readings. Have been studying fuel maps, O2 Feedback settings - basically everything - trying to figure out what is triggering (or not) apparent low fuel delivery.

So if I may, attached is a V19 log of the condition and associated CAL. I am seeing very lean 17 and 18:1 A/F from the AEM Gauge-type WB's and from what this noob sees, the options should be set to enable closed loop O2 feedback under the conditions logged. Any parallel examination/assessment that anyone wish to do while I continue trying to diagnosis and understand?

Thanks
Dan
97VR4, GM 3barMap, GM AIT, Rc550s, dual AEM Gauge-type O2's

[slava]

Originally Posted by HydeDW

I am pursuing reason for my lean O2 readings. Have been studying fuel maps, O2 Feedback settings - basically everything - trying to figure out what is triggering (or not) apparent low fuel delivery.

So if I may, attached is a V19 log of the condition and associated CAL. I am seeing very lean 17 and 18:1 A/F from the AEM Gauge-type WB's and from what this noob sees, the options should be set to enable closed loop O2 feedback under the conditions logged. Any parallel examination/assessment that anyone wish to do while I continue trying to diagnosis and understand?

Thanks
Dan
97VR4, GM 3barMap, GM AIT, Rc550s, dual AEM Gauge-type O2's

Well, i do not have v19. If anybody can post it it would be great.
Your log shows very lean 18afr. Did you calibrate WB? Adding more fuel does not help?

[HydeDW]

Originally Posted by slava

Well, i do not have v19. If anybody can post it it would be great.
Your log shows very lean 18afr. Did you calibrate WB? Adding more fuel does not help?

Yes...the WB's are calibrated now. This is the view I have at this time:
1. Insufficent fuel is being delivered at any given load breakpoint.
2. The O2 Feedback is at a constant trying to adjust (increase) Fuel delivery to reach the Target A/F ratio.
3. The Feedback option O2 FB Rich Limit (as set) only permits a +13.67% increase Fuel - insufficent to ever reach target.

Seems like a couple place were to be suspect:
a) The Fuel Map does not match the characteristics of RC550s
b) Fuel Pressure is to low - not what it should be
c) The "O2 FB Rich Limit" value is grossly too low
d) The MicroSec/bit value as mutiplier to the Fuel Map Raw value is too low
e) What other 'levers' are available to adjust fuel delivery? (after warmup)

For a) - Wizarded in the RC550C - no changes to existing Fuel Map so I assume that is ok
For b) Fuel Pressue is a constant 39 Psi (Dif) measured via Defi Gauge
For c) - Have not touched
For D - Current Value of 40 uSec in my starting CAL.

This evening I read about the MicroSec/bit value used as a mutiplier to the Fuel Map Raw values. I decided to try increasing this value incrementally as a test. At each +5 uSec, the engine started to smooth out and the A/F started heading to Target. I stopped at 65 uSec.

Now as I did this, I noted that engine RPM's increased to 1100RPM and settled there. Target Idle is 800 so I have something else to look at now.

I'm not sure if I am on the right track or not?
Even though I seem to have achieved the one objective it may be a "forced it to be that way" result and maybe I've not identified the root cause.

I'm staring at the logs...
As always, any thoughts appreciated.
Dan
97VR4, GM 3barMap, GM AIT, Rc550s, dual AEM Gauge-type O2's

This is the link to download the V1.19 upgrade
http://www.aempower.com/ems/AEMRelease051014.EXE

[BAdAzZV8]

I can't get my idle down past 1000-1100 either, no matter what I do either. I'll get it figured out one day, just haven't had time.

[FastOldGuy]

Here is a couple of pics of the gauge tech installed in the center console. Perhaps not the best place but useable non the less. I'm going to mount my AEM A/F and two new AEM EMS gauges for Knock and Boost into a cianci 3 gauge a pillar so the knock and boost will be very visable.

[mehlosTT]

Originally Posted by HydeDW

Yes...the WB's are calibrated now. This is the view I have at this time:
1. Insufficent fuel is being delivered at any given load breakpoint.
2. The O2 Feedback is at a constant trying to adjust (increase) Fuel delivery to reach the Target A/F ratio.
3. The Feedback option O2 FB Rich Limit (as set) only permits a +13.67% increase Fuel - insufficent to ever reach target.

Seems like a couple place were to be suspect:
a) The Fuel Map does not match the characteristics of RC550s
b) Fuel Pressure is to low - not what it should be
c) The "O2 FB Rich Limit" value is grossly too low
d) The MicroSec/bit value as mutiplier to the Fuel Map Raw value is too low
e) What other 'levers' are available to adjust fuel delivery? (after warmup)

For a) - Wizarded in the RC550C - no changes to existing Fuel Map so I assume that is ok
For b) Fuel Pressue is a constant 39 Psi (Dif) measured via Defi Gauge
For c) - Have not touched
For D - Current Value of 40 uSec in my starting CAL.

This evening I read about the MicroSec/bit value used as a mutiplier to the Fuel Map Raw values. I decided to try increasing this value incrementally as a test. At each +5 uSec, the engine started to smooth out and the A/F started heading to Target. I stopped at 65 uSec.

Now as I did this, I noted that engine RPM's increased to 1100RPM and settled there. Target Idle is 800 so I have something else to look at now.

I'm not sure if I am on the right track or not?
Even though I seem to have achieved the one objective it may be a "forced it to be that way" result and maybe I've not identified the root cause.

I'm staring at the logs...
As always, any thoughts appreciated.
Dan
97VR4, GM 3barMap, GM AIT, Rc550s, dual AEM Gauge-type O2's

This is the link to download the V1.19 upgrade
http://www.aempower.com/ems/AEMRelease051014.EXE

It seems possibly_that you just need to re-do the Idle vs Coolant temp table. Set the 500 through 1500 rpm cells with the same ISC percentage open..then adjust as you did before at initial setup, by raising or lowering the value till she reads close to 800 rpms. Then check what the AFR's are doing as you change the value, which is adjusting the intake idle by-pass needed to idle.

[Heikki]

Originally Posted by mjannusch

Set up the drag-race antilag stuff to around 15 degrees retarded (-15 advance), should be able to build about as much boost as you want. Your transfercase is going to hate you.

Thanks, 2-step works great now. I did not use enough ignition retard before to build any usable boost. Now the engine really barks&bangs, it feels like it will throw a rod any second...

On another subject, has anyone noticed any inaccuracy with their Kavlico 3.5bar sensor? I was doing some AFR tuning pulls and noticed how my Blitz DSBC and Apexi boost gauge both showed quite different (~+.10-.13Kg/cm2) boost readings than AEM. I know that the AEM 3.5bar sensor should be much more accurate than either of those, but I decided to check it anyway for a good measure. I hooked up a pressure source and digital pressure gauge to MAP sensor line and compared the readings between the two from 5 to 20psi.

My digital pressure gauge is calibrated to be within +/- 0.01psi up to 20psi. I noticed that the AEM 3.5bar sensor was reading up to -1.5psi less than my gauge at 19psi. I did MAP sensor wizard couple times to make sure I had the right MAP sensor values selected, but it did not change anything. I finally adjusted the "load offset" value until the gauge and AEM readings agreed. Interesting though why the Kavlico sensor, that has been touted to be "medical grade", would be this much off.

Another question, is there a way to rescale the engine load value in datalog so it would read in Kg/cm2 or psi? I am reaching a value of 10 (KPa?) right around 3100 rpms, but I am not sure if this equals to 14.5psi or what.

Heikki