ECU for my 91 VH45DE Q45

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Infinitiace1992
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Car: 1991 Infiniti Q45t KH1-C Ivory Quartz w/beige interior
Location: Detroit

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Apparently I’m in need of an ECU for my 91 Q45. Does anyone have any idea where or how to get one?


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VStar650CL
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2004 Nissan Altima 2.5 S

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Historically, N/I hasn't put regular Nissan part numbers on very many ECM's. The Nissan part number will almost always be the firmware program stored internally, and of course you can't search that. But there will generally be a manufacturer p/n on the outside of the unit, something along the lines of A56-F44 Z1F or MEC-900 560 B1. Those are what the JY's use to catalog ECM's. Get the numbers off your unit and search eBay or Google, you'll probably get hits.

Infinitiace1992
Posts: 175
Joined: Sun Jun 28, 2020 8:22 pm
Car: 1991 Infiniti Q45t KH1-C Ivory Quartz w/beige interior
Location: Detroit

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Thanks for the info

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Q451990
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ECU failure is VERY rare in that era of Q. How much do you trust the diagnosis?

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VStar650CL
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2004 Nissan Altima 2.5 S

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Q451990 wrote:
Fri May 21, 2021 6:48 am
ECU failure is VERY rare in that era of Q. How much do you trust the diagnosis?
True also. Identifix shows ECU failure being way, way down on the repair frequency list.

Infinitiace1992
Posts: 175
Joined: Sun Jun 28, 2020 8:22 pm
Car: 1991 Infiniti Q45t KH1-C Ivory Quartz w/beige interior
Location: Detroit

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Interesting you bring this up. After some thought I'm doubtful this is the issue. I had a jdm engine installed and new injectors from VH Performance and now eng is running rough. No check eng light on and it ran fine before replacing the engine with the jdm engine.

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VStar650CL
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2004 Nissan Altima 2.5 S

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Yep, that sounds more like a breathing problem or improper calibration/initialization than a bad ECU.

Infinitiace1992
Posts: 175
Joined: Sun Jun 28, 2020 8:22 pm
Car: 1991 Infiniti Q45t KH1-C Ivory Quartz w/beige interior
Location: Detroit

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I'll let him know. Thanks. Any suggestions?

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VStar650CL
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Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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One that age, start with making sure the TPS and AAC are set and working properly.

Infinitiace1992
Posts: 175
Joined: Sun Jun 28, 2020 8:22 pm
Car: 1991 Infiniti Q45t KH1-C Ivory Quartz w/beige interior
Location: Detroit

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Thank you. I'll let the technician know that.

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Q451990
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Here's a TSB from Nissan on ECU part numbers for Infiniti up to the 1993 model year. In the real world I think the only concern would be active vs. non active for a 90-93Q.

Image
Image

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Q451990
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Posts: 11473
Joined: Tue Jul 23, 2002 8:21 am
Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
Location: Columbia, SC
Contact:

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I agree that it's unlikely that the ECU is the issue for your problem. With a full engine replacement, it's a crapshoot where to look first. Leaks, sensors unplugged, damaged wiring harness, the list goes on and on.


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