Changing from 2nd gear start to 1st

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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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Hello again all,

Is there more involved than swapping my TCU from my 91 Q to one from a 93 Q to eliminate the second gear start feature?


Ryantzer
Posts: 209
Joined: Sun Aug 11, 2013 5:37 pm
Car: 1990 Infiniti Q45
Location: Phoenix, AZ

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From what I've read in numerous posts here in this forum, changing the TCU is all that's necessary.

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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Wow. Seems too simple Guess for $30 it’s worth a try. Thanks

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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Ok wish me luck. Found one on eBay for under $30. I’m assuming it’s an easy swap?

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Q451990
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Wow, that's a great deal! What's the part number? For a 93 it should be a 31036-64U20 (or the super rare never seen one ending in 64U75).

It's an easy swap, takes about 20 minutes the first time.

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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It’s the not so rare 31036-64U20. I’m not the most mechanically inclined but it does look relatively easy. It is located on the drivers kick panel by the fuse box or the passenger side by the ECU?

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Q451990
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Driver's side by the emergency brake. The part number is important to confirm you're buying a TCU that will give you first gear start. 94-95 will also work. If you post up the part number we can be sure before you buy it, or if you've bought it - take the time to install it.

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. The exact part number is 31036-64U20 from JECS and the other number listed is A64-000P45 2Z16. I’d post a pic but I have not figured out how to do that on here still.
Attachments
24467FAA-7004-4BBD-AFB5-4C4AB5FFD7B3.png
TCU (actual part I bought)

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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Not sure how I did it but the pic of he new TCU is attached

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Q451990
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Sorry, I didn't read your last post correctly. That's the one you want!

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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The updated TCU showed up and I installed it in a little over thirty minutes. Worked like a charm and now the car is so much more enjoyable to drive and clearly much more responsive starting off on first as all cars should. Thanks for the advice and help on here.

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BCC93QT
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Car: 1990 Infiniti Q45
1995 Infiniti Q45
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I have a tcu to swap for my 1990. But I haven't put it in. At this point I'm just leaving it as it is. I don't beat on it. And use manual shift if I'm going to lay into it. Im leaving my 90 museum worthy. My 95 meh.... anything goes. The 1st gear start TCU is a significant upgrade though. Especially along with a nico 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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My advice BCC93QT is to do as I did. Install the new TCU and keep the original in case at some point you want to sell it as all original. I’ve restored my 91 to look exactly as it did when new but meantime, it’s much more enjoyable to drive with first gear start. I drive this like an old lady but it’s just overall better not having to go full throttle or run through the gated shifter to get decent acceleration.

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Glad your 1st gear start upgrade is working out!
Infinitiace1992 wrote:
Sun Jul 11, 2021 6:45 pm
...... I drive this like an old lady......
....but are you the terror of Col-o-rado bouleevard (sorry, grew up in SoCal)---or maybe Woodward Ave?


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