Died on road, won't start.
 

1992, no mods, was running fine until last night as I prepared to turn a corner I pushed in the clutch, heard a weird noise and she died. She cranks fine, but never fires up. Not sure if related but earlier that day I used a jumper to bypass the Clutch interlock.
Flying_Solo was around the corner, so he towed me home and we got to tinkering, here’s what we have checked so far.
No CEL codes. The PCM seems to be fine as I still get the CEL light when car is turned on, and get corresponding codes when I unplug things like the CAS. Half tank of gas, pretty sure it was good as I’ve been running on it for half a tank.
I took off the timing belt and crank boss to check and timing is fine, the gears line up to I and E as the engine is at TDC. The crank pulley wobbles a little but I’m chalking it up to a bad pulley as the keyway is in perfect condition.
Has good spark from all 4 plugs. I pulled them all and fired them with a tester, bright steady spark. Coil packs tested fine.
Pulled AFM off and tested it according to the Haynes Manual. Everything is fine.
Fuel pump tested fine, injectors are clicking, circuit relay tested good, fuel pressure appears to be good Fuel shot across the room when I pulled the line and turned on the pump. Using a stethoscope I heard fuel flowing from the pump through the fuel rail and through the return line. If I pull the plugs after turning it over they are wet with fuel so I’m pretty sure it gets gas.
I’ve checked ALL fuses both under the hood and under the dash. Replaced the MAIN and Fuel Injection relays just to be safe. Still nothing.
I’m at a complete loss now. She cranks fine and steady but never fires up. I’ve read about every thread I can find about this and still nothing works. Any ideas?

try another CAS. you may not be getting a code for it, but that doesn't stop it from not working properly.

do you ride the clutch pedal when you turn?



The only thing you didnt do is check for spark. Make sure you're getting spark when cranking, if not check your ignitor, cas, and coilpack.

No, I was downshifting. I never ride the clutch.

Spark was checked at all 4 cylinders. Bright steady rythem to the spark on all 4.

Correct me if I'm wrong, but if the CAS was bad wouldn't I not be getting spark?

correct.

so you have spark, fuel, and air....hmmm


is the pump priming on key on and running during cranking?

I believe so. I tested all the connections on the fuel pump and it's getting the correct voltage. When I jump the GND/FP it runs. Is there a better way to test for it?

did you try starting it while you had it jumped?

did you crank it while f/p and gnd were jumped?

Yes, no change.

try taking the power off and let the computer reset. then try

Done that quite a few times. This is strange, I have spark, fuel and air but no combustion.

maybe the spark plug threads need cleaned, on the inside of the head. so that its not properly grounding itself.

I'll give that a shot. Is it possible for the spark to not be hot enough for ignition?

i know on the old ford v8's the coils wear out so i would guess they do on the newer imports as well.

you need spark fuel and timing (air is pretty much a given here...).

Seems to me timing is the issue and thats likely due to either timing belt or the electronics.

Interestingly though, I think if the cas wasn't working properly you would lose both spark and fuel...maybe there is something else at work here?

You are a smart fellar Mr Track.

it would have to be ignition timing as he's checked the cam timing. but yeah...

He checked the CAS, but I'll let him reveal the cause.

prop correct answer? lol

prop -----, :P

Ok, I lost my man card today. The exhaust cam sprocket bolt was loose, and the cam gear slipped off the pin and reseated itself in the other slot on the sprocket. So basically even though everything lined up, the exhaust cam was not where it should have been. I got so used to looking at the markings on the gear that I never bothered to look at the lobes of the cam. :lol_hitting:

This has to be one of my biggest DERP moments ever.

https://www.miataforumz.com/attachme...ine=1331930966

In fairness, I was there to check the timing and didn't notice it either. Double DERP.

Good news though. The rest of his EFI has been thoroughly checked and now he has a shiny new fuel filter. We also learned Ikea Tie Down Straps are sufficient to tow a miata.

Yeah, I guess I learned all there is about the 1.6L over the last few days. :D

sweeet ahahah

haha, congrats on getting it back on the road!