MiataGuy13

Okay so I am ALMOST done swapping in a replacement motor in my 1997 NA. The replacement motor however is out of a 1994, has lifter tick, stock, 175k miles, but runs well (Was the only running 1.8 out of an NA I could find in Michigan...) So I have everything under the car back in place, all new fluids in the trans, engine, cooling system, power steering, etc. And while I'm wiring it up I notice a few things are a bit...wrong. The orange connector (right next to the injector harness clip) that I unplugged and took off the car was a 4-prong. Once I have the motor all the way in I notice the one on the new motor is a 6 prong. I'll post pictures later. Should I have any issue swapping the 94 motor into my 97???? I'm pretty sure both motors were OBD-1...

Oh and this car is my DD and has now been down for 16 days. I need help in the worst way right now.

ianferrell

96-97 are obd2 and have an extra crank sensor used for missfire tracking (The 96 ecus were bad about throwing lotsa codes) The connector you reference could be the o2 sensor, though Idk, not familiar w/ the 96-97 harness. There will very likely be other changes that I'm not aware of, you ought to be able to swap over any differences, one way or another... But no guarantees.

MiataGuy13

Yeah that crank sensor is one of the issues, however there is no bracket or anything made on the 94 for me to relocate it to. And I'm 99% sure it's not the o2 sensor clip. That ones right next to the CAS, this one is right between the coil pack and injector harness clips. All I want to know really is will it run without them???? I'm used to my wiring harness being one big mass, not a bunch of different chunks all scattered around....well...and I'm used to my civic, which was, well, rather simple.

ianferrell

I'm not sure how the 96-97 sensors mount, but I can tell you I have a 99+ crank sensor on my 94 block right now... I had to tap the boss out for it, its m6x1 threaded, just like the crank pulley bolts. Idk, what would have 6, maybe something egr related? Find the wiring diagram and look for whatever has 6 wires going to it. If you've got the cas, injectors, coil, TPS, coolant sensor and MAF hooked up i oughta run... It'll have a crank sensor code, but I bet it runs. (note thats a guess, timing comes from the CAS on those)

MiataGuy13

Meh. It's times like these I wish I could afford for other people to fix my **** for me. I don't know **** about electronics stuff unless were talking about audio or simply replacing stuff that goes right together , so problem solving...not my strong point.

MiataGuy13

One on the left was originally on the car, one on the right came on the "new" 94 motor.

MiataGuy13

anyone?

Savington

iTrader: (31)

Looks like coil wiring to me, if I had to guess without seeing a pic from the backside and/or wire colors. The '94 would need a 6 pin connector since it needs a power, ground, two signals, and a tachometer output. The '97 can get away with 4 since it only needs power, ground, and the two signals.

Put your '97 coils on the '94 and the connectors will match up again.

The car should run without the crank sensor on the 97 - it's just used for misfire detection. It will almost definitely throw a CEL though. The '94 motor should still have the hole drill/tapped on the oil pump for the sensor mount, but it won't have the trigger wheel. You just need to use your '97 crank trigger wheel. You should also swap the balancer mount as well, since it's thinner to compensate for the thickness of the plate. Probably not a big deal but it will knock the accessory belts out of alignment. It's something you can address after the car is running - if it needs a timing belt just do it at the same time since it requires replacing the main crank pulley bolt.

In general, if anything looks different, use the '97 parts. The motors themselves are essentially identical - the only major differences are in the wiring.

Any other questions about wiring, just post pictures of the connectors in question and I should be able to help out.

MiataGuy13

Well the 6-prong connector only has 5 wires in it, probably for what you you listed though. But if I were to take that chunk of the wiring harness off and put the bit from my 97 it should all work just fine then?

MiataGuy13

anyone else??

Pen2_the_penguin

iTrader: (4)

dont do that, just do exactly what sav said, its much easier. I did the same thing with a 96 engine in my 94, it came with the 4-pin when I needed the 6 pin, I did a good ole' part swap of the coil packs and injector harness and presto chango!! Worked FABULOUS!

Preluding

iTrader: (10)

do what sav said...
Also, if you look up the wiring diagrams for Coil on Plugs, you'll find the meaning of each wire to be able to make either harness work for you with a little wiring.

MiataGuy13

Okay I swapped the injector harness over and everything is hooked up and wired how it should be, now I just need to get my exhaust back together, pull the crank pulley off the new motor (94) and put the 97 pulley on, put the crank sensor and mounting bracket on, new oil and filter, fill the trans with fluid, put the radiator and intake back in, get it all nice and full of coolant and I should be done!!! oh, and loosen the bolts on my short shifter that I just put in, they're a little too tight. lol. WHOOPS!!! and bleed the clutch...a lot.