Help with a big rich spot....

[Spooled]

I've been tuning my FAST on my turbocharged firebird. It has a T72 on a 383 (www.spooled.cz28.com). I've got everything pretty much tuned up to 15 lbs or so but I constantly have a big rich spot when taking off. When i log a pass, right when the boost comes up, the AF goes down. Both are very steep curves. They make an X. Actual AF will go down to like 9.5:1 while the target is up around 11.6 or so. It does it for about 1 to 1.5 seconds then it comes back up to the target ratio. I have no idea why this is happeneing. The O2 is telling it to add fuel. This is why it's happeneing but i can't figure out why the O2 would be telling it to add like 15% fuel or more (which is what it's doing). I don't know if this is a common problem or what. I just thought i'd throw it out there and see if anyone has experienced the same thing. I'd say it starts at about 100 kpa and it's back up to the target AF ratio at about 160 kpa. Should i log any other sensor that you might think could be telling hte O2 to add fuel? Any help would be greatly appreciated! THANKS!

 

[TurboTR]

Well it's probably just one of 2 things (or a combo)- either you move through a cell(s) in the VE table that are too high in value, or when you tip into the throttle there's too much AE vs delta TPS additive fuel. Or you might have the AE vs delta MAP active and miscalibrated, if so probably best idea to zero that out and just use the delta TPS. Is this an automatic car?

TurboTR

 

[Spooled]

Well, i don't think the numbers in the cells are too big. Mainly b/c the O2 is telling it to ADD about 15 or more percent. If they were too big, it should be pulling fuel out...right? And i do have my AE MAP active....at max it goes up to like 3% so it's not doing much. I thought about it being my AE TPS fuel. I tried loggin it and it never came off zero. I just wondered if it moved too quickly for it to see a change. At max, my TPS AE fuel is around 3 ms. It has to be this high for it to rev cleanly with a quick blip of the throttle. I'll double check the VE table for my numbers and also try your suggestion of the AE fuels. And yes, it is an automatic car. TH-350 as a matter of fact. Thanks for the help! I'm taking it to the track next weekend and hope to having it running VERY strong. Spending well over a second at 9.5:1 AF isn't helping anything.

 

[TurboTR]

Ok just change "too high" to "too far off" in the VE table discussion. The delta TPS may be too quick to catch on a log every time. If you just let it idle and tip in, alot of times you can't see the delta value in a log IME. Anyway, if you want another pair of eyes to look at your .gct and a .log file just send it to me. Also had sent you a PM.

TurboTR

 

[Craig Smith]

Where do you have the MAP AE limit set to? I would check that and set it to 100 or 110 or so. That will prevent MAP AE fuel from being applied once boost starts rising.

You can't log delta TPS or delta MAP stuff effectively. The fuel is applied asynchronously, meaning that rather than happening on the "intervals" that most everything else inside the ECU runs by, AE fuel is applied the very instant a rate of change (delta) on the MAP or TPS is detected. Data logging occurs at regular intervals, and the delta MAP/TPS stuff can happen and be long gone again in between frames of a data log.

 

[Spooled]

Craig...my map AE limit is 111. TURBO TR, I'll try and get my files to ya in teh next coupla days. Thanks for your help!