My current customer project is a customer who I built a motor for last year. He decided to have another shop assemble his car, including the VVT swap (motor is a 02, car is a '97). The shop doing the swap attempted to swap the complete harness, including chassis harness, from their donor '02 into his '97. When they couldn't figure out how to get it running, the customer asked if I would be willing to take over the project and get it figured out.

If you got this far into this thread, and you are still considering a full harness swap, I have one word of advice for you: Don't.

Just to update this connector info for this thread- many of the links in the above doc have aged out. However, Ballenger has a dedicated miata page that had every single connector I needed for this swap. The connectors are identified by their miata application, part number, and cross-referenced with their mating connector and pins. They also offer them all as pre-stuffed pigtails if you're like me and don't want to crimp pins. The whole experience makes for some very simple one-stop-shopping.

https://www.bmotorsports.com/shop/mazda_miata.php

stock ecu?

The stock ECU is plugged in, but since they only swapped half the NB fuel system in (front half), it never would have worked anyway. I'll be using an MS3 Basic for an 01-05 harness. It's not even the harness swap that makes it difficult. The NB fusebox is taller and requires a custom bracket. Still not sure how I'll mount all the relays that sit behind the NB fusebox. The headlights will never work again in this car since the motor relays left with the NA harness. No NB dash harness, so no wipers, turn signals, headlights, or HVAC. Thankfully the brake light switch connector appears to be the same. The entire fuel system is different, as I mentioned. Fan wiring is wrong, thankfully the SPM rad in this car can accept NB fans (shop lost his fans, so we'll replace). Keep in mind that this was sourced from a complete donor, so I have every relay/box that came with the '02, If you are buying a bare '02 harness and expecting to make it work in your NA, forget about it.

I wouldn't even try to estimate the number of hours of work it would take to make this work in a street car. I almost ripped the harness out and bought a new 94-95 harness to start over with (easier to get an ECU for), but the '02 harness was already in place and mostly plugged in, so it was faster to fab up custom brackets for a few things vs. re-strip the car and start over. It will still cost him a couple of thousand dollars in diagnostic and corrective work to get it running.

Lord almighty. Good thing its a racecar?

Electrical troubleshooting in the future is going to be fun.

It really is silly considering Ballenger carries all of the connectors.
I rewired my entire engine bay with freshly crimped miata connectors on the engine side and weatherpack connectors on the harness side over the course of a very lazy Saturday.
I guess all business is good business? Haha

I've stripped and wired an NB harness to work on an NA, with a 01-05pnp pro. It wasn't terrible, but I don't envy you. Wouldn't of been worth it, except the NA had no usable harness, and we had an NB engine harness. $250 in chassis harness later and it was running. With some alternator/kill switch issues, you might remember the conversation.

I've seen people use an NB harness in an NA before but they sort of ended up like they had two harnesses in the car.

I just got through wiring a 1991 CSP car 2002 motor with 99 VICS intake. basically reconfigured and re-connectored the harness to function like an NB and re-pinned the ECU connector Directly to a Hydra ECU connector. The only disappointment is following Street Prepared rules I couldn't strip all the unused crap out of it you can only change connectors or add wires as needed for other allowed mods per the rules. A couple small issues initially but I got it all sorted now and it looks clean.

Anyone in the LA Area? Need help!
 

Hello All,

I just did an Engine swap on my 97 miata with a 99 block. Evey thing is good except for the CAS/Crank position sensor and its wiring. I am getting no spark.

I am willing to pay anyone that is willing to help me get this sorted.

It is an FM2 Turbo kit with a Hydra 2.7 ECU - All programmed and ready to go.

Blew my engine at Willow Springs earlier this year and wanted to go 99 for the bigger head.

Hit me up and lets make this happen!!

Thank you

Where are you located? Have you tried a trigger test to see which sensor it's not seeing? It'll either be cam or crank. That or your timing wheel is on backwards or something. They're pretty easy to check though. Make sure all the power wires have 12v, all the ground wires have continuity to ground, and make sure both signal wires have continuity back to their respective ECU input. I think cam is BB09 or 10 and crank is BD14.

Hey Curly,

I am located Here:
https://www.google.com/maps/dir/33.8...3234513,16.48z

Honestly I am an IT Engineer but getting into Trigger Tests and signal wires is just more than I want to absorb atm. I Installed the whole turbo kit with my brother and programmed the ECU, but I am no mechanic. I do kow that the Timing wheel isnt on backwards... I can see you are in Oregon, I have family in Ashland (Shakespeare country). Want to come down for a weekend and enjoy some LA life? Food, room and board included, friend and mom have a house in Malibu and there is a couple hundred bucks in it for you or more depending on how hard it is to fix.

I have all the tools necessary, I may start digging into it this weekend, just finding the time to focus on it is the issue.

Let me know buddy, thanks. Regardless, I appreciate the input!

Hello

can somebody please point me towards the page (or post) that talks about the fuel system?

i browsed through a lot of the pages but cant seem to find it (trying to find update 1.05)

Is the general consensus to keep the return system or switch to returnless?

david

Pretty sure it's on the first page.

Keeping returnless would require a different fuel pump hanger.

99-00 rail with 90-93 regulator.

The very first post in the thread.

Duh....

I kept looking for the latest update at the end of the thread and reading it backwards...

Thanks for documenting all this!

Just finishing a swap at work, I actually prefer the 94-97 FPR, doesn't point the vacuum reference barb at the throttle body, and has a shorter barb so the fuel line can curve and clear the VVT actuator.

Huh. I have one of each, I guess I'll try them both & see what fits best. Any pics for reference?

Great thread! I have a couple of minor learnings I gleaned from my recent BP4W/VICS swap on my '94 which I think will apply to a VVT transplant as well.

1) This has probably been posted somewhere, but didn't see it on this thread. I didn't have an NB throttle cable handy, so my solution was to repurpose the upper mounting point on the TB cable pulley. I have no clue as to why the extra mounting point is there, and it requires a small mod in order to thread the throttle cable to it as shown below. 5 minutes with a dremel tool and I was good to go. This takes the ~1/2" slack out of the cable so it can be adjusted with the standard bracket. My other discovery was that the upper mounting hole diameter was the same size on my '94 TB but slightly too small on my '99 TB. This was easy to enlarge, however, a 1/4" bit is just the right size.
https://cimg3.ibsrv.net/gimg/www.mia...c1a410e87d.jpgupper arrow is to the upper mounting point, lower arrow is where to enlarge an opening for the cable.
https://cimg6.ibsrv.net/gimg/www.mia...e471af6097.jpgViola, room to thread the cable!


2) I didn't have an NB TPS pigtail, just a new connector so I was momentarily stumped on which wires went to which pins. I found a great explanation on deciphering 3-pin TPS connections here:
https://www.miataturbo.net/megasquir...23/#post649534

In conclusion... great forum, great thread and thanks to Andrew and many other knowledgeable contributors!

1) cruise control

Ah, of course!