so i put a new clutch in my Miata why wont it run?

I spent today replacing the clutch in a 90 Miata, after which i figured that I might as well replace the O ring on the CAS, I should have checked that the clutch worked first, but I was feeling confident. Unfortunately when I got it all back together. it wouldn't run well. It is missing and sounds like it isn't running on all cylinders. It also will idle OK with the clutch in, but when you let out the clutch in neutral the idle drops way down. The reverse lights also don't work. What might I have done? I think thet the CAS will only go in one way. the timing may be off but not that much. What are the two wiring harnesses on top of the transmission? Two wires are for the reverse lights what are the other wires? could I have switched the connections? What would that effect?

I was concerned that I might have reversed the wire connections, but it appears that it doesn't matter. the second pair of wires are the neutral switch. What does that effect? Could that have anything to do with my change in idle?

Sofa King wrote: I think thet the CAS will only go in one way. the timing may be off but not that much.

There's a LOT of adjustment possible in the CAS, though. I would check your timing first.

I got the car timed and it is still missing. I put the timing light on each wire and it flashed intermittantly. So there is my miss. Is it more likely that it is caused by the CAS or the coil pack. I have spares of both, so which should Itry first?

coil pack. IIRC the 90 has a separate ignitor and coil, not sure which is more likely to go. but I do know that the CAS is highly unlikely to break.

since we're here - when were the plugs and wires last replaced with OE parts? The Miata seriously prefers the stock NGK blue wires and stock plugs. Anything else, even "high performance" parts, are a step down. Plugs and wires are cheaper than a coil.

Ignitors don't usually go, coil packs are almost a consumable on 90-91s.

I hope you are right. I have a 92 that I can borrow parts from, but I will eventually have to replace what ever the culpret turns out to be.

just swapped in a different coil pack and igniter. No change! I am getting intermittent firing on #3 and #4. Could the cam sensor cause this?

Test the CAS, I know mine had a random misfire till it eventually totally failed (oddly enough, while driving it from my mechanic's shop to be put in storage!)

I am now down to "hoping" that it is the CAS because I am out of other ideas. I did just replace the O ring, so perhaps I did some damage while fumbling with it. The plastic around the electric connection on the CAS is cracked, but it was cracked before I changed the seal. It doesn't seem to have any effect on the connection itself.

Always go back to what you just did. Coil packs don't die because the clutch was changed. Nor does the CAS generally suffer simply from having the o-ring replaced.

The wires to the CAS are a bit fragile, but I'd expect you to lose spark to all cylinders instead of just two. Also, if you're going to lose fire to two cylinders it'll be 1-4 or 2-3 because that's how the coils are arranged.

Have you connected all the wires on your transmission yet? Is it possible you have a loose ground somewhere?

Holy Crap! I have to now admit to one of the stupidest things that I have ever done!!! I said that this was my car, which is a bit of a fib. This was mine for 10 years and I sold it to my future son in law who has owned it for the last 3 years, but, I have been the one maintaining it for the most part.

It turns out that the #3 and #4 wires were swapped!! I have no clue how long he was driving the car that way before we did the clutch, but the last time I would have touched the wires was when we did the timing belt and water pump 6 - 8 months ago. In my defense this is a 1.6l car and my other 4 cylinder Miatas are both 1.8 liter cars, so seeing the #4 wire on the left side of the coil didn't look wrong, but what a bonehead!! Gee, I think it should run better now. The amazing thing, is that it passed Ohio emissions with the wires crossed.

I think that I was having some issues with the neutral switch, but I have cleaned up the connectors. I haven't run the car long enough for it to warm up, but I think that I have that problem licked.

Nice! It might be humbling but it's better than finding out later, after spending tons of money on it.

I once spent a week trying to get my 351W powered Bronco to run after replacing a bunch of the upper engine parts. It would turn over, kick, but not run. I re-timed it several times before realizing I was reading the firing sequence wrong. Timed it with the correct #1 cylinder and it ran on the first try. Thank goodness I didn't damage anything!

I've learned a lot since then - I was all of 18 or so - but it's still something we can all do at any time.

Sofa King wrote: Holy Crap! I have to now admit to one of the stupidest things that I have ever done!!! I said that this was my car, which is a bit of a fib. This was mine for 10 years and I sold it to my future son in law who has owned it for the last 3 years, but, I have been the one maintaining it for the most part. It turns out that the #3 and #4 wires were swapped!! I have no clue how long he was driving the car that way before we did the clutch, but the last time I would have touched the wires was when we did the timing belt and water pump 6 - 8 months ago. In my defense this is a 1.6l car and my other 4 cylinder Miatas are both 1.8 liter cars, so seeing the #4 wire on the left side of the coil didn't look wrong, but what a bonehead!! Gee, I think it should run better now. The amazing thing, is that it passed Ohio emissions with the wires crossed. I think that I was having some issues with the neutral switch, but I have cleaned up the connectors. I haven't run the car long enough for it to warm up, but I think that I have that problem licked.

Have you considered trading in for a smarter son in-law?

I wish I could blame this one on youth! I have certainly put the wrong wire on the wrong plug before, but it never took 8 months to discover the goof!

In reply to DaveEstey:

Oh good answer! I should blame this on him!!!