Open Loop = Rich Idle???

[1999Black_Z28]

I need some help to understand what I'm overlooking. Here's my setup:

1999 Camaro, M6
317 truck heads (around 9-9.5:1 CR)
LS6 Cam
LS6 Intake
Seimens 60# injectors
Stock exhaust
2Bar OS with 12615136 2 bar MAP
This is in preperation for a turbo but I want to get things working before installing the turbo.

I am new to the 2bar OS...I started by using the stock LS6 VE table and tuning Lambda with my AFX. I can get anything with throttle tuned no problem but idle is very rich (around 11.0 afr) even though it is commanding 1.0 lambda. No matter how much I lower the VE in the 800rpm/35-40kPa cells the car still idles rich (I ran a test where I kept lowering it until I reached 10 in the VE table idle cells...still no change). I tried to command 14.7 at idle using the VCM controls and it stays rich (pulse width for both banks stays at 1.9ms). However when I force it into closed loop using the VCM controls it starts to lean out until it reaches 14.7 and the inj pulse drops to 1.6ms for both banks.

The car also idles around 14.7 with the tune in closed loop. Once again I only seem to have this problem in open loop...

My OL tune, config, and sample log are attached. I also attached my very first OL tune which has the stock LS6 VE table so you can see how much I have already removed in the idle region.

What am I overlooking???

Did I setup my OL tune correctly for the 2 Bar OS? Did I fail the MAF correctly? Is there an adder somewhere I'm overlooking (even though the log shows a command of 1.0)? Did I apply my injector data correctly? I need a fresh set of eyes to take a look.

Thanks in advance

[1999Black_Z28]

Let me ask another way...what fuel tables are referenced at idle and low MAP values? Why would I only have this problem in open loop?

[Higgs Boson]

What is it Commanding in OL (non PE)?

Check your OLFA table.

[1999Black_Z28]

Commanded lambda = 1.00 in my log

OLFA....this table right (see attached)? It is at 1.00

ECT is in the 165 to 170 range

[C5XJEDIX]

my big cam i have go lower than 1.00!im in the 0.93/' for a 14.3:1

[1999Black_Z28]

Wouldn't you leave your olfa at 1.00 (or stock) and adjust your ve table? my problem is that changes to my ve do not change my idle afr.

plus i have a small cam...z06 cam

[1999Black_Z28]

I'm still looking for guidance. Today I went back thru my notes and made a few small changes. I changed my MAF fail from 5Hz to 0Hz, I changed my DTC's to MIL on first error for P101, P102, P103 instead of No MIL, I verified my MAF failed (got a P0103 code with the scanner), I changed back to the stock OLFA table, I turned DFCO back on, and finally I re-enabled my idle proportional function.

My idle afr still shows around -25% no matter how much I change the VE table.

I decided to add a little back into my VE table in the lower MAP regions and log while in closed loop (I didn't know what else to do). My idle slowly found it's way to 14.7 but I still don't know how to proceed.

For now I think I might concentrate on the rest of the table and ignore the area's I have issues with. Once done I will combine my tuned region with the stock idle region and let closed loop handle the idle. Any thoughts???

Here's my tune/log for my SD closed loop test.

[Russ K]

Start by setting the open loop table to 1.00 at operating temp.

Russ Kemp

[1999Black_Z28]

Start by setting the open loop table to 1.00 at operating temp.

Russ Kemp

Russ, I had the open loop table set to 1.00 when I first experienced this problem (see post #1 and #4). I only changed it back to stock b/c I didn't know what else to do...

[SSUte01]

Without viewing the tune on this computer, it sounds like you're running into a min fuel delivery limit with those injectors as a result of either Engine ==> Transient ==> Min Fuel Mass (going from memory there, the name is similar, but lower it significantly, most OS are 0.032, 0.035, 0.040; try halving it) or incorrect settings for the SD 60s or a combination of both.

[1999Black_Z28]

Without viewing the tune on this computer, it sounds like you're running into a min fuel delivery limit with those injectors as a result of either Engine ==> Transient ==> Min Fuel Mass (going from memory there, the name is similar, but lower it significantly, most OS are 0.032, 0.035, 0.040; try halving it) or incorrect settings for the SD 60s or a combination of both.

This was it. Thanks for the help Once I made this change using my modified VE table the car would hardly idle it was sooo lean

I started over with the stock VE and I got it dialed in on my second iteration.

For anyone else wondering it was Engine > Fuel Control > Transient > Min Fuel Milligrams. I changed it from .045 to .023