1.8 VVT motor into 1.6 car Advice welcome.
 

Hello all. I just thought I'd share my plans along with a few questions about this swap. I came up with a 40,000 miles 1.8 vvt motor on craigslist locally for 600 bucks with all sensors, wiring from the engine all the way to the battery, full intake manifold, exhaust manifold with downpipe, clutch and flywheel, all hoses, and all solenoids and vacuum lines. The car it's going to is a 1990 1.6 car with a Megasquirt DIYPNP. The idea for the swap is to create the best possible combo with the most powerful engine and the lightest car with plans to eventually go turbo.

I have read through most of the related threads especially Savington's rental thread. I'm going to use the engine wiring from the vvt engine and adapt it to the 1.6 wiring by cutting the car harness right around the windshield washer bottle and adapting the wiring there. I do plan on using the vvtuner to control the vvt. For the exhaust I plan on cutting and welding the flange on my cat and use my current exhaust.

As far as questions I have, is it possible to use the 1.8 rear coolant sensor to run the 1.6 temp gauge? Do I need to run sequential injection, or can I just wire for batch? To use the factory ignition coils, I delete the ignitor and wire them like wasted spark coil on plugs? Do I just use the tach out on the MS to run the tach? Thanks in advance:) By the way, I know I'm crazy for trying to adapt the wiring. Let me be :) Wish me luck.

1. yes, it's the same sensor... at least I though the VVT motor still had that little gauge sender thing.
2. I would. But you shouldn't have to.
3. you'd delete the ignitor, but run them the same way. they just happen to have built in ignitors on the coil pack.
4. or contining running the factory coils/ignitor and not worry about it until you really upgrade to COPs?

1) No, the VVT engine has a different sensor. Drill and tap the heater outlet so that you can attache the original 1.6 coolant gauge sensor.
2) You don't need to, but it sure is better.
3) Yes
4) Yes

The vvt motor has one sensor on the back of the engine with three pins. I was under the impression that one of them ran the gauge, so I was unsure whether or not it functions the same way as the 1.6 single wire sensor.

I would run the factory coils and ignitor but the idea is to keep as much of the vvt engine's wiring and setup in tact for the sake of neatness so the extra work would be worth it for me in that respect. Is there a good way to mount 1.6 coils on a vvt engine? Thanks for the response. :)

zip ties?

Would something have the be tapped? I thought that there was a small plug on the outlet side that was threaded the same way as the 1.6 temp sender... or so I had read.... :) Thanks for the response.

Well to be honest zip ties are not my favorite means of attaching anything to anything....except maybe bumper covers..... I think zip ties would hurt the neatness factor as well..... I more or less like things to look like they were factory....but I'm just weird that way. I could maybe fab a bracket up and weld it to the shock tower maybe....with some long plug wires. But that seems like more work.....lol Thanks for the response. :)

Yes, one of the three pins will work if you connect it to the correct wire for the coolant gauge. I did that and it works for my setup.

Fantastic! Does it seem to work the same way the 1.6 sensor did or does it read a little hotter or colder? I wasn't sure if they worked the same way. Thanks for the response. :)

It seem to work the same as before (NA 1.8 sensors). At about 160 it hovers a little lower than the center.

Oh ok Awesome. Thanks for the response. :)

Also, are you using the individual cam and crank sensors or just the cam angle off an earlier car? Thanks in advance.

The only engine wiring you should have to adapt is for the cam/crank signals and VVT signal. You can simply cut off the stock CAS plug and wire the cam/crank signals into that. Then run the VVT wire back yourself. This should keep the amount of cutting and splicing to a minimum.

I know that's what a lot of people have done, but I'm going to try and use the VVT cam and crank sensors. Thanks for the reply. :)

That is how you hook the NB cam/crank sensors up to the 1.6 harness.

Can you just give us a regular, old fan output? I'm using the boost-control output on my MSpnp1 to run the fan in my 1.6.

If you use the 1.6L wiring harness it is really easy. It might be a lot easier than splicing a whole lot of wires at the firewall. I used the injector harness and a lot of the connector pigtails from the 01. The rest of the wiring was from 1.6L stuff.

Oh, my fault. I misread that.

I found a alen head plug in the rear on the exhaust side by where the rear neck attaches that came out and I screwed the original dash temp sensor in that seems to work fine although I had to extent the single wire a little.
I tried the allen key plugs on the other side and they would not budge.
Please post up details of how you make the stock coil on plug of vvt work with your diypnp I have same car and will be doing this soon.
Also the idle valve will need increase the valve feq (pwm tab under idle/start in TS) or it buzz's and does not work anything over 8 stops the noise I have mine a 10 and I seems fine but I am chasing so many other issues with my swap that I cant say for sure.

Please do not cut and splice the entire harness. The easiest way is to use the existing harness from the car and adapt it where needed. I transferred all the sensors, like coolant etc. over from my old block. You should splice the the Cam and Crank sensors into the CAS wiring. You will also have to splice in the throttle position sensor unless you did that previously. You can de-pin the idle valve connector so there is no cutting and splicing there.

To change over to the Toyota COP's, you will need to open the spark plug holes on the valve cover. To get them tied into the harness on the car you can gut your ignitor unit and wire into it. You can also just de-pin the ignitor unit harness and use an 8 wire plug from the '01 harness, like the fuel system connector, and wire the other side of the connector to the COP's.

How are you going to control the VVT? I am using the VVTuner from DIYAutotune. This will need sensor inputs from the Cam and Crank sensors. I wired all of them from the DIYPNP and used the pass-thru in the VVTuner to bring them back to the DIYPNP.

Please feel free to contact me.

Also, if you need a good start-up map for N/A, let me know and I will send you mine.

MX5Race, can you please post your VVT engine MAP for N/A.

Thanks,
-Raj

I've done what you're describing.
I have a butchered 1.6 harness with 94 harness transplanted over it. I don't remember why I originally did it, but it's been like this for almost 2 years now. Works great. Kind of ugly. Still way better than other cars I've seen.

Anyways, it's a pain in the ass. It's definitely doable, but there are issues:
- 1.6 harness is not sequential. if you want to run sequential, you need to add wires
- VVT has extra sensors which means - add more wires. A good amount of wires
- Soldering in that area is a major, major pain the ass. I hate soldering under the hood. And there are at least 20 wires to solder in order to join the harnesses.

You mention that you want to create "the best possible combo"... well, that would be MS3 with MS3x and a custom wiring harness. Possibly with fuse box relocated to the interior.

I also recommend skipping cops and going straight to LS coils. Same initial price, better coil.

splicing harnesses sounds like zero fun.

just run the extra wires you may need or steal from other sources, such as the unused AFM wires or charcol solenoid and such.

Don't have access to my tuning laptop to upload it, but I have it posted on www.MSruns.com • Index page

Splicing a 2001 engine harness into an early chassis is the worst possible way to tackle this project. Use your OEM engine harness and add the wires you need for VVT, cam/crank, and sequential injection.

One of the reasons that I'm not a fan of soldering on a car at all. The connection is brittle and it will break eventually in a vibrating car. If I need to connect things I'd rather run a new wire all the way to an oem connector and re-pin it. If thats not possible I'll try to use the same style as the OEM connector as a splice, failing that, weather pack.

Not as brittle as my turbine wheel or brake rotor, apparently!
Seriously, I drove about ~22000 miles with this harness in 2 different cars without failure. Use a good soldering iron, good solder, good heatshrink, cheap heat gun :)

Saying it will fail eventually, puts the eventually on the same level of all molded plastic parts will fail eventually. It might be a really long time but it will happen, eventually. Though speaking of solder, the spark fun iron is amazing, and their special blend solder has to be the best flowing non-lead solder I've ever used.

why would you use non-lead solder? gonna slap an RoHS sticker on your car? lol...

WES51 or bust!
https://www.miataturbo.net/attachmen...ine=1348163028

f that.

40-Watt Pencil Iron - RadioShack.com

https://www.miataturbo.net/attachmen...ine=1348163146

it's funny cause it's true.

Looks similar to the spark fun one, except the spark fun one has a metal case, a better holder, a better iron, and only costs 40 bucks. And I use non-lead solder because its impossible to find leaded solder, and to be honest this stuff flows better than most leaded solder.

https://www.miataturbo.net/attachmen...ine=1348163325

I'm taking the 2001 fuel injector harness I bought and adding two wires for sequential on my 1991. It seems pretty simple and gives me a pig-tail to solder in, not bad. I still need a 99 TPS piggy if anyone has one.

that's a pretty baller station actually.
and lead solder - McMaster-Carr

bought like a 2lb spool ages ago and been using ever since.

Vehicle electronics are ROHS-exempt.

That is what I used to use. It kicked ass.
https://www.miataturbo.net/attachmen...ine=1348174847

Don't be hatin. I repaired circuit boards for a living, so work wanted me to have a good station. I really do miss it, the weller I have now just does not do it. then again the tips for the Pace sometimes cost more then my current weller.

The plan is to use VVTuner to control the VVT. Are you running toyota COPs? Got any pictures? I know the holes on the valve cover would need to be modified, but do the mounting points for the factory coils need to modified as well? Did you convert to sequential injection or wire for batch? Lol sorry so many questions. Thanks in advance

Well gosh guys....I didn't think splicing the harness from the 02 was such a bad idea..... but it appears all the veterans have chimed in. Sucks...cuz I just spent an hour and a half labeling my cut 02 harness wires....Oh well I guess.

Which one is that? I have an ST115 and an ST50 with three different handpieces (TD100, SX90 and TP100) and I would love to have all three active at the same time with more deskspace available.

I am running Toyota COP's, batch. The mounting points on the coils themselves need to be removed. I bought some flat stock from Home-depot and some plastic risers and used the existing '01+ coil mounts.

Attachment 55415

It is a pace MBT 350. I loved having all 3 tools there at what ever temperature I needed. It was a truly amazing machine, unfortunately it cost a shitton.

Yeah it costs as much as my ST50 and ST115 combined. Duh. :facepalm:

Obviously decided to use Toyota coil on plugs. Gonna do them fully sequential. This is the first mock up of the setup. I need some spacers between the bracket and the valve cover and I'm considering using threaded rods and stainless steel acorn nuts on top for a more finished look. Whatcha guys think? Attachment 55820

Attachment 55821

I have no problems finding tin/lead solder. All the usual electronics suppliers stock it.

You will always be able to buy it; ALL military/aerospace electronics are ROHS exempt and are required to be lead soldered due to reliability issues with lead free; NASA requires lead in all it's soldered components. Medical electronics, computer servers, telecom equipment, Aircraft, and other critical electronics are also exempt and invariably use lead solder. NASA had 10 examples of satellites as of 2007 that failed due to tin whiskers from lead free assemblies.

However that is at the component level (high propensity to generate tin whiskers) and soldering wire won't be a problem with lead free; it can take the higher heat that lead-free requires and wire is a straightforward assembly, unlike SMD components or high pin count chips and connectors.

Tin whiskers have also been the cause of dud missiles, shut down nuclear plants (7 instances), dead radar in military jets, forced a recall of pacemakers, caused an issue with the shuttle where they were near max steering correction due to tin whiskers shorting components and forcing the rocket engines off course ...

But leaving that aside, what exactly is the lead free solder you're using? There are many people who would love to find a reliable lead free product, especially one that flows better than tin/lead; myself among them. None of the products I've tried so far are acceptable, they've all ended up in my plumbing toolbox. Best I've found so far is silver/tin/copper, but it needs high heat.

I smell a thread hijack....

Random question....should I hook up the factory knock sensor to the MS? Or is there an aftermarket type I need? Thanks

Not that anyone is really following this but I figured I'd update. Instead of my solder idea, all connections are going to be done via weatherpack connectors. I've gathered the vast majority of the parts I'll need. Now I just need a few exhaust bits and I can get started. I'm using the 22 pin bulkhead connector to connect the vvt engine harness (most of it) to the 1.6 car harness.

Link to weatherpack connectors?

So you're wiring it all into one bulk head connector and not a assload of 3 or 4 pin connectors right? Cuz that would be hack.

And make sure none of your weatherpack's carry a significant current load. Get into metripacks if they do.

And get a REAL weatherpack crimper. Seriously makes a difference. Normal "2 stage" crimpers are for crimping wire insulation, and will mangle the round weatherpack seals. Metripacks can be crimped with a weatherpack crimper but it will not automatically set the crimp depth so you'll have to balance the pin in the tool when you crimp. Kind of fiddly but not bad.

I prefer to dab solder on my crimps. And splice wires with uninsulated butt splices, then solder those.

Get serious about stress relief. good heatshrink, adhesive lined. wrap your harness with something, be it braided sleeve or if you're a real man: deray flexible heatshrink (like raychem v22 but 1/2-1/4 the cost). Anchor the harness every foot or so. I also like to pack my heatshrink with dielectric grease.

I think wiring and connectors/lines (oil, fuel, etc) are what separate "meh" builds from "awesome"

I have this set of connectors.

Here go.
Weather Pack 22 position bulkhead connector kit DIYAutoTune.com

755 Piece Weather Pack Kit DIYAutoTune.com

So you're wiring it all into one bulk head connector and not a assload of 3 or 4 pin connectors right? Cuz that would be hack.

Indeed Weather Pack 22 position bulkhead connector kit DIYAutoTune.com

Most of it's going into that one.

And make sure none of your weatherpack's carry a significant current load. Get into metripacks if they do.

The most significant load is going to be the ignition coils... Why would that be a problem?

And get a REAL weatherpack crimper. Seriously makes a difference. Normal "2 stage" crimpers are for crimping wire insulation, and will mangle the round weatherpack seals. Metripacks can be crimped with a weatherpack crimper but it will not automatically set the crimp depth so you'll have to balance the pin in the tool when you crimp. Kind of fiddly but not bad.

Got it covered.
Ratcheting crimper for Weather Pack connectors DIYAutoTune.com

I prefer to dab solder on my crimps. And splice wires with uninsulated butt splices, then solder those.

Get serious about stress relief. good heatshrink, adhesive lined. wrap your harness with something, be it braided sleeve or if you're a real man: deray flexible heatshrink (like raychem v22 but 1/2-1/4 the cost). Anchor the harness every foot or so. I also like to pack my heatshrink with dielectric grease.

Where does one acquire the Deray stuff? I'm good on stress relief. I drink heavily. Also, almost all the wiring is factory stuff. The wiring is factory from the engine all the way to where the bulkhead connector will be and the 1.6 wiring will be mostly the same up to that point. I'll be adding a small harness from the coils to the ignitor wiring, from the passenger side where the wiring goes to the idle control, tps, p/s pressure switch, and temp sensor to the bulkhead connector, and a few small wires from the bulkhead connector to the ECU. Not sure how much stress relief I'll really need on those.

I think wiring and connectors/lines (oil, fuel, etc) are what separate "meh" builds from "awesome"

Agreed

Glad to hear you have a good head about doing this right. The issue with weatherpacks is they are only rated to 20 amps. I'm not sure what the ignition coils draw but they may be ok.

Really 90% of the wires in a car are fine but some things, like electric fans, fuel pumps, and headlights, are borderline. And using it anywhere going to the alternator or starter (unless it's a signal wire) is asking for trouble.

You should probably be fine on stress relief using stock hold downs and heavy drinking. I mainly say that for anything that may be soldered. I'm a huge solder fan and I've never had a failed joint, but I understand the stance against it. I'm slowly warming up to crimping, now that I'm independently wealthy and can afford good crimp tools.

BTW: harborfreight has a hydraulic crimper that is NICE for doing big wires like battery terminals.

As for your other questions, this post is amazing:
Building your own wire harness? Check here.

Anything that draws any major current is going to stay just the way it is as far as the wiring is concerned, so I think I'm ok on that front. Good to know that they're rated at 20 amps. Didn't know that. I like soldering myself...mostly because I'm cheap. The main reason I'm sticking to mostly weather pack connectors on this project is simply the complexity of it. If something goes wrong, (which inevitably something will with a project like this) I'd prefer not to have to slice and diced though all the heat shrink and everything to find one wrong connection. I'll have to check out that HF crimper. Sounds like something I could use. Also, your link is amazing. I've been trying to find a decent source for that kind of stuff for some time now. You wouldn't happen to know where to find shielded wire would you?

Does anyone know if the flange on the 01-05 "downpipe" bolts up to a 94-97 catalytic converter?

dont think so

When I'm buying wire I usually just search for "tefzel" in ebay or "pretinned."

I like to use DIY's harnesses, but if I need extra wire I get the really tiny strand, tinned milspec stuff from some cheap website or ebay. I don't bother getting like super crazy name brand milspec wire because nothing else in the harness is that way and I figure using pre-tinned stuff already puts me ahead of the game anyhow. I'm pretty sure mcmaster has cheap shielded wire too.

More knowledge for you: get yourself MIL-T43435B lacing cord. You can get more than you'd ever use for like $10 on ebay. More handy and lighter than cable ties. Worth it's weight in gold. We use this stuff everywhere on our aircraft. You only see cable ties to hold something to a hard point. Bundling wires you'll always see lacing cord. It's also really great to help tie down self-fusing silicone tape, which I've found can sometimes let go on the edges.

Here's another link:

Motorsports ECU Wiring Harness Construction

I'll keep that in find next time I need wire. The wire I'm using now is actually all scavenged from another Miata wiring harness. I looked at McMaster and they have something similar to what I was looking for. Thanks!

Does that lacing cord have a temperature rating? Looks like something I'll need to pick up.

Before I started I actually read that entire article you linked :) Then I went looking for some of the connectors and products mentioned.....Ridiculous stuff...... Retardedly cool and expensive at the same time.

I think the milspec stuff has to be rated to like ~300*F

I take this stuff flying daily, next to a jet turbine; so I have 100% confidence of it lasting in my car.

Yeah that link is over the top, but I take some of the bigger ideas and try and filter it down to something more practical I can do.