If you drive it aggressively for 20 minutes on open highway, you should get most of your VE table... try to operate the throttle in a progressive manner, and try to hold it steady longer.
then go to the drag strip on open night and log a few WOT passes.
Joe,
might have a problem. Justin@Blackbear thinks my wideband isn't reading accurately since even after autoVE I have VE values over 100%. He says that EFI live misinterprets the analog voltage from the LC-1. e.g when the lc-1 voltage is 2.5 EFI live interprets it as 3v. Basically he said I need to rewrite the equation for the LC-1 AFR PID. He recommended getting a volt meter and measuring the voltage from the LC-1 with setting the AFR to 16:1 and 11:1 with the DVT.
Yes, this is a common issue with using analog output on most any wideband.Originally Posted by GMCtrk
As for holding a gear, you can use DVTs to specify the gear you want and as long as you don't surpass the value in {C6152}, it will do what you tell it to do. I'd suggest doing more of your VE tuning in 2nd gear for higher RPM than first gear (on the street) as well, as you'll be able to spend more time in each cell.
I'm still confused why this inaccuracy exists. Is every LC-1 putting out different voltages from the factory that cause the EFI live PID to be off that much? How have you ended up modifying the PID in the past? In EFI live it is (AD1 x 3) + 7.35. I would assume all of the LC-1s are programmed to output 0 volts at 7.35 AFR and 5 volts at 22.35 AFR
The default/factory programming in the LC-1 gives 0V=7.35AFR and 5V=22.35AFR, which is represented by equation afr = (AD1 x 3) + 7.35...
But it looks like you're seeing the problem of voltage offset...
Do this:
- connect FlashScan to vehicle,
- connect LC-1 to FlashScan V1,
- program LC-1 to output 3.5V, observe what EXT.AD1 says on scantool,
- program LC-1 to output 1.5V, observe what EXT.AD1 says on scantool,
- program LC-1 back to default.
Note:
- connect the serial cable to the LC-1 OUT connector, connect the DB9 end to your laptop;
- connect the terminator plug to the LC-1 IN connector;
- to program the LC-1 use the LM Programmer software from Innovate;
- after you reprogram the LC-1, you have to remove power for a moment, then reconnect power.
For example:
if scantool reads say 0.5V too high consistently across the range,
then the equation would become afr = EXT.AD1 * 3 + 7.35 - 0.5
This can be put in the calc_pids.txt file, we can show you how.
What he said. I forgot all about LM Programmer.
That looks like a good idea. Only problem is my laptop doesn't have a serial port. I guess I could try those serial to USB cables though.
Bringing this one back up.
I put a cam in this past weekend and tried doing some autoVE'ing this evening. I got the thing idling pretty well by reducing fuel at idle RPMs, adding timing, and adding idle airflow (some other changes too).
Anyways, I went to go do the autoVE and I was idling rich rich (13s) and getting all kinds of AFR swings and real KR. Got my BEN averages and updated the VE table, fired it up and I was idling in the 16s! I would make a log and go back and everytime it would just switch from rich to lean and vice versa. It looks like to autoVE this thing, B4322, B4323, B4331, B4330, B4324, B4325, B4328, and B4329 all need to be set to 0. I think the computer was adding airflow when it was idling rich and then combined with the BEN changes made it just swing to really lean.
Any other tips for tuning a cam off the top of your head? How are you all setting up the VE table prior to doing autoVE? All cells below 1200 rpm I pulled fuel, but 1600 and up I should add how much? 15% across the board? 5% at low RPM and more up higher? Thanks.
I never had to fool with the Idle Learn Limits like that. I took out almost all the Low Rpm Airflow in the Learning Tables B4512- B4515 (per the Idle Tutorial). I guess I understand your logic, but I am not sure how the PCM will handle it when you limit the Idle learn Limits like that...
As far as fueling, generally a cam will require 10-25% less fuel in the lower 1200 Rpms. It all depends on your cams VE profile. I have less fuel from Idle to ~ 2800 Rpm/60 kPa, then 5-15 % above stock at that point. The tough part is from 1200-2800. Low kPa's, less, higher kPa's more.
Idle will always be tough as IAT and ECT swings can make day to day tuning of VE tough. I usually try to get an entire fuel map done in one day..keeping the ECT and IAT steady. If you decide to re-enable Trims after AUTOVE, I and others have more experience in that. If you stay open-loop, do you have any custom OS's available to you? That might help on Idle AFR swings.
I use a slightly different method, but I think if you can just log everything in one short tuning session, it is better than a morning vs evening run and then trying to combine the two results into one.
At least that has been my experience. Good luck..
Idle:
What were all those tables initially (I looked up a stock 12212156 F-car file and all of those were something like +/-0.50, one of them was 3.00).
B0101 VE table initial bump:
15% may be too much unless you have also increased displacement significantly or added modest boost...
try 8% and do a trial run at light-medium load (pay attention to knock)...
- if you find the BEN's are all lowering B0101 by about 5 or more % then 7% was too much.
- if you find the BEN's are all raising the table by more than say 3% then 7% was not enough.
Yes, "skew" the initial bump up as you said and as Weatherman said (i.e. less bump up at low load, more bump up around peak torque).
The closer you can get your initial bump up to the actual VE, the easier it will be to get a good B0101 table.
What are the specs on your cam...?
Last edited by joecar; April 6th, 2010 at 02:25 PM.
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