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Old 03-21-2003, 08:35 AM   #1
Jon [in CT]
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Default USDM STi Injectors

As you may know, 2000+ EJ25 engines in the Impreza, Legacy and Forester use a UJ fuel system (see http://www.endwrench.com/pdf/fuel/FtFuelEmmisionW00.pdf), whereas the WRX and JDM STi use a Denso (aka ND for the old name - Nippon Denso) fuel system. What type and size injectors will the USDM STi use?

I would have expected Denso, but I've been told that the USDM 2.5 STi has reverted to a version of the UJ fuel system. The UJ injectors are said to be the same impedance as those on the WRX and JDM STi, but the connector is blue, they are side feed, and they flow roughly the same as the JDM STi (pink) injectors. Oh, and the so called "green brackets of death" apparently would interfere with the side-feed arrangement and are gone from the USDM STi.

BTW, can someone clue me in to what the acronym "UJ" expands to?
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Old 03-22-2003, 07:40 PM   #2
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Jon
I found this
http://www.aeromech.usyd.edu.au/ther...wirl/swirl.htm

Seems "uj" means ??????

Sorry I can't as yet do better than this.
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Old 03-22-2003, 08:35 PM   #3
Jon [in CT]
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Thanks, Wombat North, but I am confident that the term UJ, when seen in Subaru service literature, is almost certainly a reference to a fuel injector/system manufacturer's name, not a concept.
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Old 03-22-2003, 10:34 PM   #4
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Possibly "UNIASIA-JECS"

JECS=Japan Electronic Control Systems=the brand of ECU in all Subarus.
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Old 03-23-2003, 12:39 PM   #5
Jon [in CT]
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Quote:
Originally posted by xephyr
Possibly "UNIASIA-JECS"

JECS=Japan Electronic Control Systems=the brand of ECU in all Subarus.
Bingo. Except the company's name is Unisia Jecs Corporation and, although UJ did supply the ECUs for versions of the WRX PRIOR to the New Age WRX, current WRX ECUs come from Denso.

So would a switch from the Denso fuel system to the UJ fuel system say anything about the USDM STi's ECU? Could FHI have been nervous about the abundant reflashing of WRX Denso ECUs? Might FHI have worried that Denso ECUs may no longer comply with OBD requirements that the OBD computer be "tamper proof?" Would a switch to UJ ECUs solve these problems?
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Old 03-23-2003, 12:53 PM   #6
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Quote:
Originally posted by Jon [in CT]

So would a switch from the Denso fuel system to the UJ fuel system say anything about the USDM STi's ECU? Could FHI have been nervous about the abundant reflashing of WRX Denso ECUs? Might FHI have worried that Denso ECUs may no longer comply with OBD requirements that the OBD computer be "tamper proof?" Would a switch to UJ ECUs solve these problems?
Maybe it wouldn't make them tamper proof, but perhaps it would keep hacking them from being cost effective.

If there are only a few thousand WRXs with this ECU being sold worldwide per year, perhaps people who research ECU flashing (like ECUTEK), would deem it "not worth their time" to hack these ECUs knowing they will only sell a few hundred units per year.
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