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Discussion Starter #1 (Edited)
Well I fixed my TPs and I am now retuning the fuel. I dont like the idea of pulling out a lot of fuel with the AFC so right now it is set at -10% across the board and I am dropping fuel pressure to pull fuel. The thing is, Ive dropped the FP about 10psi and have seen very little change in A/Fs. The Vf signal is showing the TCCS to be trying to add fuel almost all the time although my wideband is showing that the car is running near stoich at cruise. WOT A/Fs went from 10.1 to 10.4 with the 10psi fuel pressure change. This doesnt seem like much to me and I dont know if I should keep dropping the pressure. Right now it is at 36psi with no vacuum. The car runs great and isnt backfiring as much.

Those with experience: Does this seem typical? Any downsides to dropping the FP any further?

Thanks
-Zach

Edit: I can email the LM-1 logs for those who might want to gander.
 

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Moderator, l337 M0d3r4t0r
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12,222 Posts
FP affects everything idle and crusing/boost.... TCCS has to compensate for everything except when you go open loop.

What size injectors and turbo do you have. You may just have too much injector for the turbo. Remeber the car it's self likes to run rich by default.

Why not pull fuel via safc and retard base timing a little to even it out?
 

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Be original, not a copy
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Correct, pressure does not directly correlate to volume. I use fuel pressure to move the a/f no more than .5 either way. You can make dramatic changes in fuel pressure for more significant changes with a/f but it will either cause poor atomization or stuck injectors. When adjusting the AFC pull the ECU fuse to reset the maps. Remember, on the TCCS there is short term trim and long term trim. If you reset everything back to the base map (pull the ECU fuse) you will be "modifying" the base map instead of the TCCS modified map. Know what I mean?

I would not lower fuel pressure too much more if at all.
 
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Discussion Starter #5
Thanks guys.

I have the good ole lex/550 :rolleyes: with the pretty much standard 60-1 CT26 @ 15psi. I dont want to back off base timing because I dont want to lose any off-boost throttle response.

I think I will try resetting the FP to 40psi, pull the fuse and drive it to get the base maps accustomed to the new FP. Then log some WOT pulls and try to tune as quickly as possible with the AFC. Or should I tune WOT right after resetting the ECU?
 
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