pcf_mark

iTrader: (1)

Is anyone in this forum running and LS7 with BigStuff3? I have one running but is not running very well. I was hoping to find someone else with the same project. Before I start exploring the tables I wanted to see what other tricks I could learn.

My issue is the AFR is set to 13.6 - 14.0 but the actual AFR is 10.0 - 10.5. I am focusing on getting the engine to idle and with all the raw fuel it is tough. I ran a log file of it if anyone can help.

Thanks!

danglerb

Don't run it much with the AF off that much, plays hell on cylinders doesn't it?

pist0lpete

iTrader: (3)

I would definitely check in with the guys in the tuning section of possibly if bigstuff3 has their own forums. I know some of the guys running LS7's have switched them over to an LS2 computer but the advantages of bigstuff3 (especially in boosted applications) are numerous of course.

Hugger Z

iTrader: (4)

PM 'builder'. He is building an Ultima GTR with the BS3. I know it was running as it was tuned on the W2W engine dyno by Meanie himself.

MIGHTYMOUSE

iTrader: (59)

the target AFR only works if you are in closed loop wideband operation.

if you have closed loop and the wideband hooked up, then make sure your closed loop enable parameters are met, and that your allowable negative fuel correction is spun up to say 25%

any further questions go for mightym0use@comcast.net

71CamaroLS1

If your fuel table is way too rich, the wide band correction won't be enough to put it in range. That seems to be what you have going on. Select the cells in the fuel table down in your idle range, and lean them out about 30 to 40 percent. Your wide band sensor will then be in range to correct to your desired ratio. You can then use the wide band correction factor to fine tune the fuel table further - you want the wide band correction to be a "fine tune" to correct the last few percent. The fuel table is the primary mechanism for tuning the fuel curve.

MIGHTYMOUSE

iTrader: (59)

i disagree, unless you have seen the log. it could be any of many things

71CamaroLS1

Well, you are right that there are other things which can affect fueling under steady state (steady throttle, like at idle) conditions. The three that I can think of are:

1. Engine displacement set wrong in system parameters.
2. Fuel injector flow rate not set correctly in system parameters.
3. Excessive cold start fuel enrichment.

But assuming you entered 1 and 2 correctly, and didn't mess around with the default cold start fueling parameters, the only possible reason left for such rich mixture is that the fuel table is set up way rich. Mine was - I had to cut the idle range fueling nearly 50% from the table supplied with the BS3 ECU (which was supposed to be "pretty close" for my engine).

MIGHTYMOUSE

iTrader: (59)

or
4. closed loop operation is not selected
5. closed loop parameters are not set appropriatly and not allowing closed loop to become active

im sure the guy has enough info now to tell us exactly whats going on when he gets back