Got a S/C with piggyback? Wanna try something?
12-08-2006 | 03:20 PM
#41
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From: Seattleish, WA
btw, did you install anything yet?
12-08-2006 | 03:52 PM
#42
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From: Overland Park KS
My Supra does the same thing. I repeatedly see recommendations for people to pull their EFI fuse before a race or a quarter mile pass, but I can tell you first-hand what's happening...the engine is running lean. My car is tuned for 11.8:1 at 16 psi and after an ECU reset it runs closer to 13:1 for a short time. Car is much quicker, but we all know 13:1 is really pushing it.
The ECU seems capable of adjusting +/- 20%. My car idles around 14.7:1 per my PLX wideband. I can slowly add fuel and after 20-40 seconds the ECU subtracted the fuel I added and I'm right back to 14.7:1. Once I pass about 25-30% on my fuel computer (Apexi S-AFC), the stock ECU seems incapable of removing any more fuel and the fuel ratio finally begins to dip. I can do the same by turning up the fuel pressure to an excessively high level. I'm still not sure whether or not the ECU would take those fuel trims and apply it to open loop (WOT). So in other words, would the ECU take the 25% correction in closed loop and add 25% to the 16x16 map that comprises the open loop table? Supposedly it does, but I haven't been able to prove it yet.
The ECU seems capable of adjusting +/- 20%. My car idles around 14.7:1 per my PLX wideband. I can slowly add fuel and after 20-40 seconds the ECU subtracted the fuel I added and I'm right back to 14.7:1. Once I pass about 25-30% on my fuel computer (Apexi S-AFC), the stock ECU seems incapable of removing any more fuel and the fuel ratio finally begins to dip. I can do the same by turning up the fuel pressure to an excessively high level. I'm still not sure whether or not the ECU would take those fuel trims and apply it to open loop (WOT). So in other words, would the ECU take the 25% correction in closed loop and add 25% to the 16x16 map that comprises the open loop table? Supposedly it does, but I haven't been able to prove it yet.
Same with my GS400
12-08-2006 | 04:36 PM
#43
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From: Los Angeles
Sorry for the vague post. The "This" i was referring too was the ECU compensating for the piggyback and needing to be reset. And no, Christmas came along and stole my money, so I haven't had a chance to install any fuel mods yet. No later than March. Until then I've been taking it as easy as possible. Thanks for the info as usual midiwall.
12-08-2006 | 04:51 PM
#44
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From: Seattleish, WA
'k... obviously wait for someone with the 7th and AIC, but I would suspect that yes, the ECU will compensate for the 7th piggyback overtime - it's just the nature of the beast.
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