The Definitive "VVT swap into 90-97 chassis" Megathread.
#284
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I am nearing the end of my swap and I have quite a few hanging grounds off the 1.6 harness on the passeger side of the car near the cylinder head. I am using a square top IM and do not see anywhere immediately obvious to ground these wires. I am thinking to just extend them and ground at the chassis.
What is the accepted "best practice" for this?
What is the accepted "best practice" for this?
#285
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I am nearing the end of my swap and I have quite a few hanging grounds off the 1.6 harness on the passeger side of the car near the cylinder head. I am using a square top IM and do not see anywhere immediately obvious to ground these wires. I am thinking to just extend them and ground at the chassis.
What is the accepted "best practice" for this?
What is the accepted "best practice" for this?
e: To clarify, this is for a 90-93 car. The 94-97 cars use a bolt/stud bracket thingie that bolts to the block and connects to the ECU grounds next to the throttle body, and you can just transfer that over to the 99-05 motor. The NB fastens all the ECU grounds to the intake manifold, so the IM is a good place for them.
#286
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I am nearing the end of my swap and I have quite a few hanging grounds off the 1.6 harness on the passeger side of the car near the cylinder head. I am using a square top IM and do not see anywhere immediately obvious to ground these wires. I am thinking to just extend them and ground at the chassis.
What is the accepted "best practice" for this?
What is the accepted "best practice" for this?
Edit- listen to the smart guy. I changed mine later.
#287
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I attach all the ECU grounds to the intake manifold. I typically repurpose one of the EGR studs for this.
e: To clarify, this is for a 90-93 car. The 94-97 cars use a bolt/stud bracket thingie that bolts to the block and connects to the ECU grounds next to the throttle body, and you can just transfer that over to the 99-05 motor. The NB fastens all the ECU grounds to the intake manifold, so the IM is a good place for them.
e: To clarify, this is for a 90-93 car. The 94-97 cars use a bolt/stud bracket thingie that bolts to the block and connects to the ECU grounds next to the throttle body, and you can just transfer that over to the 99-05 motor. The NB fastens all the ECU grounds to the intake manifold, so the IM is a good place for them.
To Ziggo, I may have exaggerated a bit, yes, I am referring to the two ring grounds coming off the harness with the injector connector.
#288
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
So, I need some help (admittedly, very explicit hand-holding here) as I don't want to do this twice.
A 6-speed went in with the VVT motor. On the car side, I have the following
-two bullet style pins, and two white plugs
on the transmission side there are
-two white plugs, one black plug with two spades
I have seen notes written on MT that you just switch the plugs and it works, but can someone be very explicit about what exactly goes where? I have no clue which is the reverse or neutral switch.
Thanks,
A 6-speed went in with the VVT motor. On the car side, I have the following
-two bullet style pins, and two white plugs
on the transmission side there are
-two white plugs, one black plug with two spades
I have seen notes written on MT that you just switch the plugs and it works, but can someone be very explicit about what exactly goes where? I have no clue which is the reverse or neutral switch.
Thanks,
#289
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
To figure out which one is which on the car side, look at your old transmission and do the same thing, then match the connectors up.
![Party Kitty](https://www.miataturbo.net/images/smilies/birthday[1].gif)
#290
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Take a multimeter and probe the two connectors. In neutral, one of them will show continuity. That's the neutral switch. In reverse, the other one will show continuity. That's the reverse switch.
To figure out which one is which on the car side, look at your old transmission and do the same thing, then match the connectors up.
![Party Kitty](https://www.miataturbo.net/images/smilies/birthday[1].gif)
To figure out which one is which on the car side, look at your old transmission and do the same thing, then match the connectors up.
![Party Kitty](https://www.miataturbo.net/images/smilies/birthday[1].gif)
![](https://www.miataturbo.net/images/smilies/ky.gif)
For reference if anyone is as lazy as I was trying to be, for a NA chassis with a 6 speed going in, the bullet connectors from the car go to the black connector on the trans. I ended up crimping spades where the bullets were and jammed them into the black connector (keep in mind, the connector is tight and you _will_ need to isolate the spades somehow. I used silicone tape). The white ones just plug together and are a non-issue.
Got my swap running at the last minute on Saturday to make a cruise Sunday. Beat on the car mercilessly for 250 miles and it was the best. Thanks Savington and everyone who posted information in this thread for the help!
Last edited by albumleaf; 05-31-2016 at 09:48 PM.
#293
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Just for anyone doing this swap, to reiterate my earlier comments.. Make sure you do the wiring for the coil packs so both wires are long enough to reach both coil packs. An earlier version of the original post had the coil pack wiring colors mixed and my car would start until I switched them on a whim. I just experienced the same thing yesterday helping my friend get his vvt swap car started. I suspect he had a very old printed version of the original post that he was working from, but it doesn't hurt to have the cables long enough just in case.
#297
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I have not seen any of that in my car after hundreds of laps at Sebring and Homestead. Are you aligning the powerplant frame correctly? If you have the angle on the powerplant frame wrong it will raise or lower the front of the engine depending on which direction it is off. I have seen the intake tube hose clamp at the TB rub the hood ever so slightly when the adjuster is in the wrong spot, but the VVT solenoid shows no rub marks.
#298
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
When I say rub, I mean polish. The contact is so slight that the top of the VVT oil line gets shiny. It would not surprise me at all if tolerance stacking between the hood bracing, hood mounts, body, subframe, and motor mounts will cause you to either have or not have this interference based on nothing but random chance.