Running on three cylinders

[wh0aitznic0]

Ugh, I just bought a headache. DOHC hatch. It's only running on three cylinders and I've deducted that it's #3 by pulling the spark plug wires till there's no effect. I put #3's wire on one of the strut tower bolts and it was arcing.

Any ideas on what's causing the misfire? My first guess is injedtors/injector harnesses. The last owner was a retard and thought the misfire was just a bad motor mount. :bash

[EDT007]

Try changing out the plug, may sound dumb but once saw a plug crack on the inside to the point the person was having numerous mis-fire codes/issues. Also if you want to see if it's injector/harness issue try and either borrow/buy a tester that clips on and flashes if it's getting a signal. Goodluck.

[BlitzRPS13]

I'd try new spark plug in #3 and a new spark plug wire. Or try unplugging the injector clips one by one when it's running.

[sirfallsalot243]

Start with a plug, follow up by compression testing that cylinder.

[BlitzRPS13]

Just make sure if you do a compression test you have the car on a charger and you have warmed it up and you hold down the gas fully when you crank it.

[DxZoo]

Start with the plug, then check the injectors. I had this exact same problem and it was my #3 injector. If its not either of these check your comp and if not that id guess ground/your harness is fucked somewhere.

[wh0aitznic0]

Thank you everybody. I'm gonna hit up autozone for a plug and the junkyard tomorrow morning. :)

[germz]

Same thing happened to me last week. I had brand new plugs and #3 was misfiring but the plug wire was still arcing. I couldn't find any faults on the ignition circuit so I moved on to the fuel injector. I hooked up an injector pulse tester and found that the injector was stuck closed.

If you are unable to identify anything that would disrupt the ignition circuit, I suggest you inspect the injector for proper operation and delivery

[mxexux]

If you want to know if its the injector for sure just swap #3 with another one. If the misfires follow the injector then you know for sure. This would save you a trip to the junk yard if its not the injector.

[projectRDM]

Odds are it is an injector, they're prone to going out on DOHC S13s, I've sold and/or replaced a good several dozen in my days.

[Pacman]

Odds are it is an injector, they're prone to going out on DOHC S13s, I've sold and/or replaced a good several dozen in my days.

VERY common, had two go out back to back on the old S13. Put a screwdriver on the suspected injector and listen for clicking. If its clicking, it indicates that the injector is working. Listen to the others for reference.

If its working, check the spark plugs porcelin for black streaks indicating that the spark is arching through the boot. Look in the boot and look for a grey streak (indicates the same). Make sure the wire isn't arching and shorting to ground through the insulation. Run the engine at night and move the wires around the valve cover and look for the blue arch. If it is ignition, do a good tune-up (cap, rotor, plugs and wires).

If it still isn't found/solved, run a compression check. Make sure its not abnormally low. If it is, add a teaspoon of oil and see if the compression increases. A burned valve is possible, I've had that on my old S13.

If all is good, start car and take a test light, ground clip and probe pin on injector harness. A flashing light will indicate that the computer is firing that injector.

I'm sure that you'll find the problem before you get to the compression test. You've been spoon fed.

[wh0aitznic0]

Thank you all. Car runs beautifully now. Problem was injector itself. Grabbed a new injector from the junkyard and swapped it in.

[BlitzRPS13]

Good to hear.

[blitzsti22]

same thing happen to me, my third cylinder had very low compression so i just rebuilt it