running on two cylinders after 1.8 swap
 

i swapped a fresh 1.8 into my '93 miata over the winter. It now runs on two cylinders. new plugs and wires. i bought a new to me set of coils that i was told were good, still only have spark on 1 & 4. only thing i could think of was the extension to my CAS wiring, but i soldered them, and they all looked fine when i went back and checked them.


anyone have any ideas?

I would think it is your coils. Or your igniter.

i know...

i already bought a used set of coils, i hate to keep throwing money at them. i wish there was someone local with a set i KNEW was good.

would a bad ignitor fire one coil and not the other?

I know this is basic . . . but . . .

Double check that your plug wires are routed correctly. IIRC, the routing differs between the 1.6 and 1.8.

You'd be surprised (well, maybe not) how many times this has bitten me whenever I've changed plug wires or coils.

I'm pretty sure it's right. Even if they aren't, wouldn't it still send a spark. Just at the wrong time?

Are you using all of the original coils, ignitor, cas, same plug wiring as 1.6 with 1.6 coils? Or, did you swap in something 1.8?

I have ruined (flooded) plugs due to the wires being routed incorrectly after cranking for awhile. That could cause the lack of spark. Triple check your wire routing. Just for kicks, I would try switching 1 and 4 with 2 and 3.

same ignitor, and CAS. new plugs and wires. i bought a used set of coils i was told were good already.

btw, i checked for spark, with the car running, with a timing light on each plug wire. so that rules out plugs, wrong firing order etc.

Stuck injector(s)? When I was de-turbo'ing my 1.8 I put my old tan top injectors back in that I had cleaned over a year ago. Two of them were stuck which I fixed by lightly tapping on them with a mallet. A 9V battery is a good way to test the injector out of the car. You should hear a click. Two of mine didn't click till I whacked them a few times.

i know that i'm not getting any spark on two or three. i checked all four injectors and heard them clicking away while the car was running.