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Discussion Starter #1 (Edited)
Who has done 12V Fuel pump mod for their NA-T?

I'm planning on rewiring the fuel pump ECU to run on 12v mode at all rpms. The tech article on mkiv.com states that there are 2 operation modes for the twin turbo supra ( http://mkiv.com/techarticles/12v_mod/12v_mod.htm ).

I was wondering if the same 2-mode function also applies to the NA supra's fuel ECU?

I'm going to spend the weekend on my TE-44 turbo kit tweaking my a/f ratios with my LM-1 wideband and SAFC2. Is the 12v mod necessary to maintain consistency out of the walbro fuel pump I also have installed? I'm not seeing any lean spots on my a/f gauge at WOT between 4-5K rpm like the problem in the tech article states but i figure I ought as well try the fuel mod to see what will happen and hope I can get some input from those that have done this mod and what differences you noticed.

Last Question :) : The car was professionally-tuned months ago and now my LM-1 is showing a consistant a/f ratio of 10.3 on WOT so I want to try tuning the car on my own to lean out the fuel a bit. At Hi-Throttle setting on the SAFC2, should I shoot for an a/f ratio of 11.5-12.0 from 3500rpm+ or should I try achieving those #'s starting at a higher or lower rpm?

Specs on car: Stock compression, 330cc injectors, with a TE44 turbo that starts boosting at 2000rpm and hits full boost of 9psi at 3500rpm. Thanks in advance guys, the search button is not working at this time :chicken: .

~Chris
 

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Addicted to Boost
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315 Posts
I was wonderig about that 12volt mod as well. I also have a question for you, Howd you go about getting that cap to fit tightly on the fuel tank after opening to do the pump. When i tightend my cap back down, the center part that has the pump hanger hanging off of it still floats and moves freely... i cant seem to get the cap to go down any further. You have any tips?

Oh and isnt that pushing the limits of your motor at 9psi with stock compression? i mean, id be careful.
 

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TE44 NA-T
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Are you running off of the wastegate spring? If so, what psi spring?
 

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Discussion Starter #4
adversary said:
Are you running off of the wastegate spring? If so, what psi spring?
I'm running off the wastegate spring with some boost spike at WOT.

I hope to get some input whether or not to give this 12v fuel mod a try.
 

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TT This
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917 Posts
I have the 12v Mod done. I've been running it for a few years now. No problems with it at all. If I remeber correctly you should be able to follow the MKIV write it and you'll be fine.
 

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Discussion Starter #6 (Edited)
NinetyFiveNA said:
I have the 12v Mod done. I've been running it for a few years now. No problems with it at all. If I remeber correctly you should be able to follow the MKIV write it and you'll be fine.
I just took a look at the Fuel ECu that the NA supra has and the ECU is different then the TT supra ECU. I also have the diagram for the 2jzge fuel ECU and it shows a different type of ECU on the NAs then what is pictured for the TT Supras. The connector is also in a different position. I'm guessing the NA supras do not have 2 modes of fuel operations like the TT does. If anyone else has another viewpoint, please let me know. As of now, I'm aborting this mod.
 

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TT This
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Well....I did the mod a long time ago. I followed the MKIV.com write up when I did it...I guess I don't know what to tell ya. It's been fine for me
 

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Discussion Starter #8
NinetyFiveNA said:
Well....I did the mod a long time ago. I followed the MKIV.com write up when I did it...I guess I don't know what to tell ya. It's been fine for me
Nah, the search function finally worked for me; I did my research on everything talked about with the 12v mod and the results are very mixed on its effectiveness. Some said it helped with their lean spots; some said there was no effect at all; some said it makes the fuel pump run hot for a longer period, causing the car to run leaner after a while, and one person had a small fire on the fuel pump ecu. My car isn't having any lean issues with the walbro pump, this mod is something i thought i would do just for the heck of it.
 

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TE44 NA-T
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I asked Dave H if i had to do the 12v mod. with my walboro. He said it wasn't necessary.
 
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