The Definitive "VVT swap into 90-97 chassis" Megathread.

I got my swap done, fired up right away and idled well on the MS3Basic basemap. I drove the car around on Saturday to rough in a VE table and Autocrossed the car on Sunday in the pooring rain without hiccup. The only pending issue I have currently is my tach still does not work. I wired the ignitor wires blk/wht and yel/blue together. There is a 1k ohm resistor in the Diag box from when I had COPs on the car as a 1.6 between -IG and +B. Having thread thru this thread multiple times I am still a bit confused on what I need to do to get the tach working again. Here are the 3 common trends I see in this thread about getting the tach back
1) wire Black/White and Yellow/Blue together at the ignitor harness - this redirects the tach back to the cluster
2) wire the Tach output pin on the ECU options plug to the Black/White wire on the stock ECU harness
3) wire the Tach output pin on the ECU options plug directly to the Yellow/Blue wire on the cluster harness plug
There was a bit of discussion around this, but no body seemed to verify what worked and what did not.
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
It depends on the year of the chassis (i.e. the wiring) and which coils you are using. You have VVT coils with no tach output, so you need to use the ECU to drive your tach. There are probably OEM wires which already run from the ECU area to the cluster, so just figure out which wire to connect the tach output to, and then configure the tach output appropriately.
So on my 1991 Federal car, it appears I would need to wire the Tach Output from the MS3 Basic to ECU pin 2I which is the yellow/blue wire for Igniter Terminal E. I am curious why this is not done internally in the MS3 and requires and external wire run to solve.
I prewire my 90-94 units this way in case someone upgrades...
So wiring Tach output from the MS3 to 2I on the ECU connection will bring my tach back.
So I wired pin10 on the DB37 connector, which is yel/grn to 2I on the 91 ECU harness which is yel/blu and got a no start which is odd to me. Guess I'll just run pin10 to the cluster itself
stock 01 VVT coil near plug. Toyota COPs came off because they did not fit in the valve cover without significant trimming and no options for a mounting plate. I ran a wire from the ECU Tach out to the cluster and wired it to the white plug pin H which us yel/blu and I got the tach back.
Just want to confirm NB Crank sensor wiring positions from the sensor to harness connector.
On the crank sensor connector - The red is for 12v power, blue is signal and black is the ground. The equivalent harness side connector would be matched with wh/red 12v, grey/red for signal and black blue for ground. Thanks.
On the crank sensor connector - The red is for 12v power, blue is signal and black is the ground. The equivalent harness side connector would be matched with wh/red 12v, grey/red for signal and black blue for ground. Thanks.
All three intake manifolds have the same throttle body location. Any 1994-2005 throttle body can be used, but the 99-05 TB is more desirable for its internal idle valve routing, which makes plumbing for custom 2.5" cold air intakes or intercooler piping much simpler. Using the 99-05 throttle body will require that you change the TPS and IAC valve pigtails, but this is a fairly simple modification. The 1990-1993 throttle body cannot be used on the 99-05 manifold without an adapter, and you lose the benefits of the linear TPS on all 94-05 throttle bodies.
Use a 1999-2005 throttle cable. It will bolt directly into the NA chassis and fit perfectly with the NB engine. The NA cable is too long.
Use the NA throttle cable on the NB throttle body mounted to a NA intake manifold.
Since you would be putting a NB throttle body on an NA intake manifold, you would use the NA throttle cable. This mainly has to do with where the throttle cable bracket resides on the intake manifold. On NB manifolds, the bracket is much closer to the throttle body than on NA manifolds making the NA much too long on an NB manifold.
Use the NA throttle cable on the NB throttle body mounted to a NA intake manifold.
Use the NA throttle cable on the NB throttle body mounted to a NA intake manifold.






