Hey, ok so basically I blew the ring lands on my old pistons, rebuilt the motor is arp studs apex hg oem rings etc etc when I finally got it back in and cranked it up, it is only running on 3 cylinders. The 4th cylinder has gas on top of the piston but the plug isn’t wet with fuel when I pull it out after running. I’m lead to believe it’s a stuck open injector but I’m not sure.
I did test for spark, it is there, timing is correct, all 3 other pistons are carbon coated but Cyl 4 piston is still super clean.
All injectors and coils find before rebuild so I’m just frustrated.
Any ideas? Check grounds? Buy new injector(s)?
Help me out I want to drive so badly.
check the continuity between the injector leads. make sure you get a reading of 0. if you get a reading of 1 throw the injector out. also run the car and put a large screwdriver to the injector to listen for the quick snapping sounds one makes. if it is quiet and the rest of the injectors are making snapping sounds replace it or check wiring.
you should be able to check the wiring by hooking a small 12v LED to the harness end of the injector plug. run the car you should see it pulse or do something. this should work but i have never tried it.
if you dont get anything you could have the LED ends backwards just turn it around or maybe it doesnt work and means nothing. but if you do get pulsing then you know 100% that that is fine.
also disconnect all the injectors to stop the engine from starting and flooding. remove the spark-plug and reattach the spark-plug wire outside the engine. ground the thread of the spark-plug to a clean ground source like a bolt. I use the shock tower bolts. have a friend turn the car over and watch the plug spark. if the spark pulses then your ignition is good if not then replace spark-plug do it again. if still nothing replace the ignition coil and repeat.
I assume this is an SR.
Yes s14 sr20, the 4th cylinder has spark, no issues with ignition. I will check injectors tonight, I’m not great with a multimeter but i’ll give it a shot. Worse comes to worse I have access to a spare set of injectors I will try.
Anyone know anything about what would cause an injector to stay stuck open and if replacing it would fix that? Or could there be issues with a ground somewhere causing it to stay open?
If I remember correctly the ecu is responsible for grounding the injectors at the specific events.
Just swap 4th injector with another to test it. If the problem moves, you know it’s the injector.
Solved: replaced injector, all is well.