Ronny

iTrader: (1)

on the whats up display i see:
1. Learn
2.Learn CR

i believe Learn in green is active. yellow is inactive.

what is LEARN CR?

RBob

iTrader: (1)

Lean Cr: in highway Lean Cruise mode.

Good for gas mileage. This is both an increase in AFR and added SA timing to compensate. It is able to take an engine from 26.4 MPG on a stock ECM, to 32 MPG on an EBL setup.

RBob.

DM91RS

I sure need to work with my tune because my mileage since the 3.73 rear gears went down a bit. But I am running in open loop also. Are there advantages running in OL or CL when having a mild engine such as mine. [LT4 stock cam] Especially in regards to fuel mileage?

zipfast

iTrader: (2)

For mileage you want to be in Closed Loop so that you can use Lean Cruise mode. Which will be pretty easy to adjust with the EBL setup.

Ronny

iTrader: (1)

i ran OL with my prior 7747 and tunercat for a while as an experiment. fuel mileage sufferred significantly. car ran better but that was due to imperfect tune. since gas was $3+/gal(ethanol blend) i came back to CL. with EBL i am confident i can run CL (enjoy the fuel mileage), and possibly command a slightly diff stoich(enrichen a tad) and see if car runs better.

Dominic Sorresso

Guys,

RBob and I connected my VAFPR vacuum port this weekend, so now I am using vacuum assist to modify fueling. My gas mileage went from 20 up to23.5 mpg. All without Lean Cruise Mode enabled yet. The throttle response is pretty great.

DM91RS

I checked at fill up today and averaged 19.59 with mixed driving and only a few WOT runs. This is if the DD speedo box is correct as it still has low speed spikes at times. I keep the speed to 65 on the interstate which is 2000 rpm's with the 3.73 rear.

It sounds like I have some work to do with the tune. The first step being what sounds like to start running closed loop again.


Dominic.........that's good news about the VAFPR. Glad to hear it works that well.

DM

Fast355

iTrader: (2)

My last tank got me 551.8 miles on 30.6 gallons of gas. That is 18.0 MPG. I was doing roughly a 60/40 split, city/highway. That was running both A/Cs on High due to our 100+* heatwave.

Dominic Sorresso

DM,

It really runs very nice. RBob can chime in since he rode in it. The throttle response is really impressive. The accelerator pedal feels "stiffer" because it doesn't need as much movement to get the same response.

DM91RS

That's cool............how does it improve the throttle response?

Dominic Sorresso

DM,

RBob and I talked about why using a VAFPR would enhance throttle response.
Bob seems to feel that by lowering the pressure at PT, of course the PW will become wider. This means that the fuel is delivered in a pulse over a longer duration rather than dumping it all at one time. Possibly makes for more even delivery of the fuel. Also less fuel needs to be atomized at any one point in time possibly creating a better mixture. It also may help explain the improved fuel mileage. The injectors may be operating at a more efficient duty cycle over the rpm band. This is all conjecture on my part and perhaps RBob and Fast355 would add what they think.

DM91RS

Dominic.............thanks for the reply. I am just glad to hear that it works well if needed.

Right now I cannot get the car to go into Closed loop again. I only ran the 1st maybe 4 out of almost 80 bins on closed loop. Even after reading/searching most of last night I must be missing something. I have the enable temp set back down to where it was in the stock EBL bin. What else would it be? The stock o2 is showing that it's reading.

Thanks DM

Dominic Sorresso

Do you have the Option Words for Open Loop Cruise and Idle unchecked?

DM91RS

Thanks.

Yes Option Word 1...Bit 2 and Bit 3 are both unchecked.

RBob

iTrader: (1)

Check the transient open loop TPS% quals. Both should be set to 100% (Transient OpnLp - Open TPS% Delta & Transient OpnLp - Close TPS% Delta).

The other area is the go to closed loop O2 values. If the O2 value doesn't go higher or lower then these values it won't go in to closed loop. (Closed Loop - O2 Upper/Lower Go into closed loop).

There are also some timers that you may want to double check.

RBob.

DM91RS

Thanks Bob .............will do.

DM91RS

Thanks for your help guys as it was not a program issue. I noticed today when running the WUD that the O2 was not going to it's full normal range and then totally stopped moving at around 700 mv. So up went the car and found of all things the O2 connector (harness side of course ) melted against the header. After a parts run and reconnection it went into CL finally. Boy those oem O2's sure take a while to heat up just idling.

I guess it was just a coincidence that I tried CL about the time it went out. Must have moved the wire around when changing oil last week.

It's kinda like the more I fix the more I tear up.

DM

Dominic Sorresso

DM,

Achems Razor states that: All things being equal, the most simple > > > explanation is probably the correct explanation."

DM91RS

Yep........I hear ya. I went through all the parameters several times and "knew" it should work.

Oh well.........Thanks again.