Is this safe???? High LTFT
12-12-2007, 12:33 PM
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Is this safe???? High LTFT I installed headers and a fabbed 3in exhaust dumped b4 the axle about a month ago. Using EFI Live, I Reset fuel trims and have logged over the past few weeks. My LTFTs are avg +9.2 bank 1, +10.7 bank 2. Max are +18 bank 1, +20 bank 2. This seems VERY lean!! I have the innovate LC1, but will not have it hooked up for another 2 weeks (need USB adapter and new bung). I have varied knock. Log from 2 days ago had 7 instances, 2 at which were 4.7 degrees of retard. Todays log showed one instance of 1.7 degrees on a high rpm 100% tps run. My duty cycle was at 78% at full throttle, that seemed to close to the 80% max recomendations I hear of. Is it safe to keep driving the next couple weeks before I do Auto VE/ SD tuning? I will prob stick with SD after the tune. What and where can I go to help richin up the AF till I do this? Any info on my situation is appreciated. Oh btw, When I logged with the 7 cases of knock, It was not your usual "saw blade" knock. It was more instant then tapered off smoothly. It seemed to happen once I got up to speed, got off the gas then slightly got back in it. Kinda like it was being held back till I gave a lil more gas. No miss fires reported. I do keep getting a high idle code, but I think I may have the cruise cable a lil hung up. Thats the least of my concerns right now. Thanks guys....
12-13-2007, 10:15 AM
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Oh btw, When I logged with the 7 cases of knock, It was not your usual "saw blade" knock. It was more instant then tapered off smoothly. It seemed to happen once I got up to speed, got off the gas then slightly got back in it. Kinda like it was being held back till I gave a lil more gas.
12-14-2007, 03:11 AM
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Do you have an exhaust leak between the engine and O2s? Pre O2 exhaust leaks can skew fuel trims to a false lean condition which the ECM responds by dumping excess fuel (showing + fuel trims). You did say that you just installed headers recently, an exhaust leak is the first thing to comes to mind. Do your spark plugs show overly rich with the + fuel trims being that high or do the plugs look like the AFR is correct with the fuel trims being that high?
Jay
Jay
12-15-2007, 12:08 PM
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Correct me if I'm wrong, but you aren't lean. That is the correction used to get you to 14.6. Your VE and MAF are off if you want to get down to it, but the computer is correcting your fueling. Get those closer, as Frost suggested, and the correction gets closer to 0.
12-15-2007, 01:53 PM
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You are Correct Rob. I find so much misinformation about Fuel Trims. ECU is adding more then normal fuel to keep it at stoich. Needs tuned, but will not hurt anything. It has not even set a lean code yet, so computer still can get it to stoich.
