89 323 SOHC - injector issues - computer, sensor, or mechanical? Does anyone know?
 

The car was driving great, as always, when the second and fourth cyls cut out. So, I limped it home, and replaced the cap, rotor, plugs, and wires. I tested the coil, distributer, timing, fuel pump, fuel filter, post-filter fuel pressure, battery, alt., and compression and visually inspected all the wires and vaccume lines I could find, as well as all fuses, etc. All checked out great. However, my 2nd and 4th plugs are coming out wet with gas. if I run it, it will burn, but it smokes like crap. Seems to be that the two injecters are stuck open, but how does that happen to TWO of them SUDDENLY? Is there a sensor, or something I'm missing here? It's driving me nuts. Thanks very much.

injectors
 

With my 626 if I recall correctly two injectors fire at once, so if two of yours were not getting pulses that connect them to ground but instead staying connected to ground by a faulty injector circuit maybe, it would make sense. You can compare the two that are not working with the two that are by seeing what the voltage is on the injector circuit. If it is different (prob would be lower as it would be more negative more of the time) than that is a good suspect. -Ken

if it turns out that the injectors are the problem and two of them stuck open at the same time, i would say that it's a combination of old injectors and bad gas. all it takes is one bad tank of gas to make an old component bite the dust.

pull the injectors and send them to www.injector-rehab.com for a rebuild. they do awesome work. i sent my rx7 injectors off to them and my car has seen more linear power gains as well as much better gas mileage since. i have a discount program that i go through, but they take forever to finish a set of injectors for me now. before, i would have them back inside of a week when i was paying regular price.

Swap the (alleged) faulty injectors with the functioning ones to determine if the problem isn't further upstream.

ok, so I plugged a test light into each injector plug, one by one, to see if it was a mechanical or electric problem. Turns out that for whatever reason, as soon as I turn the key on, the two injectors open. I don't even turn over the starter, just key on - injectors 2 and 4 open. When I plug the test light into the other two (cyls 1 and 3) there's nothing until I turn over the engine, then it flashes, as it is supposed to. So the injectors are physically fine, it's electrical for sure. What the hell, eh? Thanks for the suggestions so far, by the way.

Ecu would be a good guess.