The Definitive "VVT swap into 90-97 chassis" Megathread.
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
If you cut the firm-ish line off the OEM plastic fitting, it's barbed underneath. I slip 5/16" fuel hose over that with a hose clamp and I've never had any issues with it.
The Definitive 1990-1997 VVT Swap Megathread.
You will need to retain one of the fuel injection fittings from the 01-05 fuel rail to use as an adapter on the 99-00 fuel rail. I prefer to use a 90* adapter instead of a straight adapter to aid fuel line routing around the alternator.Alternatively, you can use an aftermarket fuel rail and aftermarket fuel pressure regulator.

You will need to retain one of the fuel injection fittings from the 01-05 fuel rail to use as an adapter on the 99-00 fuel rail. I prefer to use a 90* adapter instead of a straight adapter to aid fuel line routing around the alternator.Alternatively, you can use an aftermarket fuel rail and aftermarket fuel pressure regulator.

I have both 2004 fuel rail and 1999 fuel rail and I cant figure out what you mean by retaining the fuel injector fittings from the 2001-05 fuel rail. The fittings look the same to me.
Also, doesn't the VVT motor FPR regulate fuel to be @60psi vs 43psi for the 90-93? I'm using 2004 injectors with the 90 fpr, would the decrease on pressure affect the injectors? I am running a ms3 so fuel tuning will be done, obviously. Has anyone added an adjustable FPR? What about this one? http://www.miatacage.com/adjustable-...egulator-90-97
Last edited by btabor; Jan 3, 2016 at 08:49 PM.
Here is a picture for reference. 2004 fuel rail on top, 1999 with 90 for on bottom. I don't know which fitting from 2001-05 "that needs to be kept" you are taking about. I'm confused
What color wire are you guys tapping of the injector harness for the vvt solenoid? Is there a way I can find out which one is the 12v without having the car on?
Could I use a 12v 2amp source from my megasquirt instead?
Could I use a 12v 2amp source from my megasquirt instead?
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
I'm referring to the plastic adapter attached to the fuel line that clips onto the fuel rail. You can use an aftermarket adapter too, but the 01-05 rails have a nice 90deg fitting that helps clear the alternator. The decrease in fuel pressure is not an issue, but if you want, you can run an aftermarket adapter.
I tap the 12v wire on the CAS plug for VVT power. On the injector harness it should be one the white/red wires that you can grab power from.
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Please read the original post in its entirety before asking questions.
IAC Valve:
If you are swapping to the 99-05 throttle body to upgrade to the internally routed IAC valve, you will need to swap the pigtails for the TPS and IAC wires. The IAC valve wiring is not sensitive to polarity, so you can simply swap the pigtail without worrying about which wire goes where.
If you are swapping to the 99-05 throttle body to upgrade to the internally routed IAC valve, you will need to swap the pigtails for the TPS and IAC wires. The IAC valve wiring is not sensitive to polarity, so you can simply swap the pigtail without worrying about which wire goes where.
Thanks Savington for all the info. I kept the original vvt engine harness and used Deutsch connectors on both ends. I think it will end up working pretty well. Looks stockish




Awesome info in this thread; it helped me swap a VVT into my to my NB1. I got it started with the stock ECU (small miracle), and I have my MS3 Basic waiting to go in, but I'm not sure which wire to tap on the injector harness for the 12v VVT actuator. I'm using the 2003 injector harness, and I think it's the white wire with the blue stripe. If anyone can tell me for sure before I spice into it, I'd appreciate it!
Thank you!
Thank you!
Awesome info in this thread; it helped me swap a VVT into my to my NB1. I got it started with the stock ECU (small miracle), and I have my MS3 Basic waiting to go in, but I'm not sure which wire to tap on the injector harness for the 12v VVT actuator. I'm using the 2003 injector harness, and I think it's the white wire with the blue stripe. If anyone can tell me for sure before I spice into it, I'd appreciate it!
Thank you!
Thank you!
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Logically, there is one wire that provides +12v to all four of your injectors. It will be the same color going to all four injectors, so look at a couple of your injector connectors, figure out which wire is shared among them. That's the +12v.
Im in the process of doing a 01 vvt w/90k in my 94.. I already droped in the motor this past weekend.. I swap to the 94 na thtottle body to use my org tb plug etc.. Is that ok?
Im geting a 99-00 nb fr from my buddy and maybe fpr too..(ps can someone post me pic on how to route the fuel lines, what goes where to where) i have an idea but dont want to do it twice..
I have a vvtuner here at home, i dont have any instructions on where to wire thing up..
I just read this entire thread and seems like im on the right track 👍👍
Feed: rear hard line to fuel rail quick-disconnect fitting
Return: FPR to front hard line
5/16" fuel line
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
The ECU doesn't control the 94-97 alternator. It has on-board control and doesn't need any input from the ECU. Just plug the 1.6L alternator harness into the 94-97 alternator and don't touch any ECU settings.
I knew the answer at one point but I can't remember anymore. I think the VVT blocks are BSPP and all the older ones are BSPT. That banjo fitting shouldn't work with tapered threads.
Seems like it would make sense that the VVT blocks have straight threads there for the banjo but I don't know for sure. Also not sure if it makes a non VVT block a no go for adding VVT. maybe straight male thread could be forced in or a light re-tap before shipping it off to the machine shop for bore hone and clean would work.







