cyl #4 misfiring (ka24de)

joemon · Nov 27, 2011

my 91 ka24de all stock the other day while i was driving started misfiring while going home.

symptoms are:
-really rough idle
-great loss of power
-sounds like a sti
-little white smoke out the tail pipe
-little back fire
-kinda smelly exhaust
-no check engine light on

+i checked and adjusted timing back to stock
+getting all spark (but noticed my spark plugs black)
+no arcing in spark plug wires (good)
+dizzy good working order
+coil good working order

+next i pulled plugs out with car on and cyl#4 had no change

+next i checked the injector wire plugs and all were plugged in
+so i pulled each off with car on and again no change in cyl#4

+next i checked the resistants of each plug and plugs 1-3 all resistant except #4

so all testing is pointing to cyl#4 injector...

now im asking is it just the wire bad (power from ecu or ground)
or
bad injector mechanically not in working order..

if its a wiring problem can some1 direct me to a wiring diagram for the wiring of the injector
or
another way to patch this up for now (wire bypass or splicing to another wire)

yes i have searched here and google and other 240sx sites

any help would b nice

-thanx guys

norton240 · Nov 28, 2011

sound like the problem i had on my #1 cylinder

is there any corrosion on the injector plug for cylinder 4? if so just get some contact cleaner, maf cleaner or wire dryer n spray it in there or just unplug it n plug it back in a shit load of times

could be a leaky injector, if so just pull the fuel rail with everything connected n put a rag underneth it n turn the key on to run n check to see if any fuel is coming out

could also be low compression in that cylinder but id check the first 2 first

joemon · Nov 29, 2011

ok i just swaped my cyl #4 injector with cyl #1 (easier to get to) and now my cyl #4 is working now but Cyl #1 is not working

so i went to pick n pull but the 2 240sx they had all had motors gone out of them.

is there other injectors from other cars i can use that pick n pull will have cars for?

Riedell · Nov 29, 2011

I would go ahead and replace the injector.

Buy a new one or a re manufactured one. Make sure you get a resistance value of 11-14 ohms across ALL injectors.

Edit: don't take the chance of putting a used one in there that you dont know the condition of the injector.

jesse1378 · Dec 13, 2011

if i were you i would check all your injectors.....pop the fuel rail up and turn the key forward make sure non of them are dripping. i just had to replace 2 of mine..i almost bought use (40 bucks for 4) but i opted to get new...77ish each at autozone. now i have 2 new and 2 old.

cyl #4 misfiring (ka24de)

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