I've done something dumb I'm sure. Did the timing belt on my new to me JDM engine, fired it up. It idles fine, but revs weirdly. Put it in fixed timing mode on the mspnp2, the timing mark when the light is on plug 1 is roughly 180* off from the timing marks. If I put the light on plug2 it's in time at 10*. What did I do? I'm going to recheck everything later tonight, but figured I'd see if you fine folk know anything off the top of your collective brains. This setup ran well before, if the timing was so far off would it even run....? I'm assuming I've screwed up the belt setup, and just need to recheck all the things.
If the timing belt was off a true 180* the engine shouldn't run at all. I'm not a miata or MS guru, but my first thought is to check your firing order. If you had a couple ignition wires out of place, it could run but would give you the unusual rev symptoms and explain the timing light confusion.
The engine shouldn't run if the timing is that far out.
Are the other cylinders running consistently at 10 deg like number 2?
Most likely problem is a failed damper. That lets the outer ring of the damper (the one with the mark) rotate on the inner ring.
Pull the #1 plug and drop a dowel or the oil dipstick down the hole. Turn the crank clockwise and watch your dowel/dipstick move up and down. Stop it when the piston is at the highest point of the travel. The timing mark should be at T. If it's not, you have a slipped damper.
Winner winner chicken dinner. The pulley was off - the silver mark in the picture is where the pulley on top should have a mark (it's on the other side...)Now the timing is right, but it's idling at 2-3k. I'm assuming intake leak somewhere.....
Glad you found it! A new damper is a good idea at this point. Make sure it’s for the correct variant.
High idle is pretty much guaranteed to be a leak post throttle body. Always look at what you just did, the leak will be something you touched like the PCV valve or a vacuum line.
In reply to Keith Tanner :
Yeah - I swapped on the other good damper for now, would like to get a ATI, but will have to wait until I get it all back together and testing done for what's left of my tattered budget.
Unfortunately I've touched pretty much everything to touch on this engine .... It came in from JDM fleabay, and looks like it sat for a while. I did all the normal seals, but when I took off the injector rail they fell apart so I swapped on the old intake manifold + injectors (since it was running before headgasket + low oil pressure - it never actual blew, but it wasn't looking good....).
I just had to redo the front main seal (phew), but rechecked the belt - looks like it's rubbing oddly :( I'll have to gather my infos tomorrow and post again....
Doesn’t have to be an ATi, just one that isn’t coming apart :)
The plastics around the belt have a tendency to deform from oil and refuse to go back into place. The one behind the timing belt pulley is the worst.
Sounds like you’ll want to spray around with carb cleaner to check for leaks for sure. Injector seals are a good place for them.
All of my Flyin' Miata tools are coming in handy - front main seal press and crank holder are the knees of the bees
