vvt in na chassis sanity check with MS3x
 

As the title sort of states. I am doing a 1.8 swap into my 93 chassis. I just wanted to put my thoughts out here and see what everyone thinks. This car is my DD and I cant afford to have it down for a terribly long period of time.

That being said, my current plan is to use the entire vvt engine that I have. Throttle body, through header is included. I already have a 94-97 internally regulated alternator, so I plan to use that instead of the unregulated version.

Because of the ms3x I plan to use the nb cam and crank signals instead of the na cas that I currently have. In order to do this, my understanding is that I can simply splice the wires as needed to power both units (I do have an entire engine harness for the 01 engine, so I will not have any issues running wires as needed.) By doing this I would simply run the cam signal into the 3x board, and the crank signal into the main board. Shiuend and I were talking and he mentioned something about needing certain mods in order to read the odd triggers on the crank wheel and such.

Which is where my first question resides. My MS was originally a :brain: MS1 unit built approximately September 2009, that I converted to ms3x with :brain: assistance around 2 years ago. Can anyone clarify if I need to open my MS3x box, or should everything plug in, wire in, etc etc, and be good to go?

Secondly, I intend to do two things with this swap, 1 is budget. I will be retaining the vtcs (sp??) for the time being. And I plan to keep as much as I can of the 93 wiring. This brings me to a few more questions. Is there anything that needs to be done to the vtcs, should I wire them into something to hold them open, or some other method to retain a somewhat factory operation? Or should I just disconnect that and leave it be?

Lars keeps yelling at me to pull the head off, put a 94-97 headgasket on and run a reroute (this car does get tracked) Keeping with the budget goal here, Is that entirely necessary? I know that the 01 engines have the modified headgasket to compensate for the lack of flow in the back of the head. I have the capability to do a reroute, I just dont want to have to do it if it is not entirely necessary, especially considering that this engine is staying NA.

Regarding the rest, I plan to run wires for the two extra injector wires, the knock sensor incase I get a wild hair and decide to run knock sensing, run a wire to drive the tach, and wire everything else up the way it currently is wired into the ecu.

Sanity check, Am I missing anything? am I doing something entirely the wrong, hard way? :hustler:

I swapped a 00 engine in a 91 just 2 weeks ago. I found it easier to remove the entire 1.6 engine harness and use the 1.8 engine harness. The 01 connector is different than the 93 though, so you'll have to do some rewiring.

I used the VR inputs with pullup for both crank (main-24) and cam (ms3x-32).
Don't bother transfering the 3 sensors on the 93 (green temp sensor for the ecu, little temp sensor for the dash and gray thermosensor for the fan).
Let MS control the fan and use the gray temp sensor on the 1.8 engine. It has 2 signals, one for ecu and one for the dash. The one for the dash is violet/white iirc.
The easiest way to get your fuel pump running is to just run a wire from the MS fuel pump output to the black/yellow fuel pump relay under the steering column. Just splice into the light green wire.
For the air temp sensor, you connect it to pin B (Black) and pin G (Red/Green) of the AFM connector (polarity doesn’t matter).
Tacho output of the MS can be connected to the yellow/blue wire going to the 1.6 igniter (which you no longer need).
01 is returnless, so you need to replace the dampener on the fuel rail with a fuel pressure regulator from an NA.
No need to run extra wires for the injectors if you're using the 1.8 harness. They're already in there :)

Since I dont have the entire 01 harness, I will actually need to run two additional wires for fuel, additional wires for the vvt and other small things. Because of this, Im thinking of running completely new signal wires for the air temp sensor instead of plugging into the maf wiring connector.

The only thing I dont follow right now is the "VR inputs with pullup for crank (main-24) and cam ms3x-32" I understand that you are saying cam should be on pin 32 ms3x and crank should be on pin 24, but im not sure what the pullup signal is, and If I already have it currently.

The fuel rail is an issue - the damper is in the wrong place on the 01 rail, you need a 99 rail with the damper on the front, otherwise things will interfere. You'll still need to grind off a bit of the intake manifold where it hits the 99 rail, but that's easy to see.

I ran into an issue where my 94 throttle cable was too long for the NB motor. I either need to make a new bracket to hold it further from the throttle body, or get an NB cable. Not sure if you'll run into this with your 93, but you may have issues here.

Other than that, I'm afraid I'm not much help.

I know the throttle cable will be an issue, but that is a 5 minute fix. So just to be sure, I do in fact need a 99 fuel rail.

Dumb question, but why do I need to make the system return? I know there is a reason, I cant recall why.

I think this is an excellent opportunity to build a completely new harness. It would totally be worth the money to spring for the 12' MS3x and MS3 harnesses. And yes, I'm fully aware of your budget. But getting GOOD QUALITY automotive wire that is prelabled will never bee any cheaper and terminate in the right connector anyway.

Here's a link to a fairly recent verison of my harness. It has both the miata side and the ms3 side. You may want to wire it differently but whatever works.

https://docs.google.com/a/y8s.com/sp...0E&output=html

12'?

how about 18" of each.

I woudnt be opposed to that, Running the wires I have now straight into the two db37 connectors, and running whatever else I would need off of that as well (tach, 12v, gnd, check engine, etc etc.) Im assuming you were referring to the wiring that diy provides? my only concern is that I do not see the main db-37 connector for sale on there, but im sure that a call to them would solve that.

But first things first, I can get my hands on a 99 fuel rail, Do I need to do that? or is there a way to make the 01 rail work?

And is there anything internal to the ms3 that I need to do to properly read the crank and cam signals? (or anything I need to check this weekend?)

@Gryff - of course you will have to open up the MS because you want to drive the VVT - you need to set up the MS for that...

Have you seen my VVTswap thread in the Engine performance section?

Sven

Thats exactly why im asking. Electronics are voodoo and witchcraft to me, and I was under the impression that the vvt pin 27 on the 3x board could handle the vvt with no issues or changes.:hustler:

I do not recall, I will read it tomorrow when I have some free time.

That should be true, but you WILL have to open up the MS and WIRE it...(inside and from the MS to the VVT actuator)!

The biggest issue I think Gryff has is figuring out if his MS was originally built with the VR circuits, or the older circuits that would only read the NA CAS. Realistically once he has the VR circuits is there any reason to run the CAM sensor to the expander card as opposed to where he is already running it on the main DB37?

he should be able to use the opto in for the crank and expander board vr input for cam.

Is the 99+ crank sensor the same as the 96-97?

This.


:brain: I havent messed with na8's very much, but I believe that they still ran on the single cas on the exhaust cam instead of intake, but no crank sensor until 99. so no.

there's definitely a crank sensor on the front of the 96-97 motor a CAS (or cam sensor) on the cam.


I just dunno if they are the same, but im pretty sure the typical opto input you're probably using now will work for the crank input, so then it's just input the cam into the expander.

I'd have to double check the rising vs falling edge and the opto circuit might have to be reversed in polarity, but it's a simple switcher-roo with a few changed jumper wires on the mainboard.

If I built the MS in 2009, the chances it has the VR circuit on the mainboard are nil.

ok, Is there anything I need to do/ check to figure out if I am set?

Use the charcoal can wires for the VVT solenoid, expect noise on the TPS so severe that you have to run EAE, get a 1994+ fuel injector harness, drill a hole in the floor for all the new wires.

Just go slowly and be methodical. I've done this twice and I did better the first time than the second for some reason.

My charcoal canister has been gone for so long, I honestly am not even sure if I have the wires for it anymore. I can check for them this weekend, but I would rather just run new wires to the ecu tbh.

Two free wires (one is white/red for glory), factory colored, that can be pinned or soldered at the computer, and located near the VVT solenoid...and you don't want to use them?

Wait, the canister connector fits the VVT actuator?