'94 KA24DE Running Super Rough - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

pignose.007 · 06-11-2015, 05:48 PM

Hey guys, I just finished building my KA and dropping it back into my car, and it will start and fire, but idle like absolute crap. When it idles, the engine will drop RPM's and eventually die over a period of about 45 seconds to a minute. When it is idling, the entire engine shakes quite a bit, and it also sounds like it is misfiring somewhere. I have a few variables on what it might be but any advice from you guys would be great.

1) I have a tiny crack in one of the vacuum lines that snakes through the intake, but I wouldn't really think it would cause the engine to run THAT badly.

2) I checked all the resistances for the fuel injectors and #'s 1,3 and 4 checked out with a 11.2 ohm resistance which from my understanding is within OEM specifacations. (11-14 ohms) #2, however put out a reading of 3.8 ohms, which leads me to believe that the fuel injector is bad. I back-probed all of the connectors, so I know that it is not a faulty wire or ground.

3) Could it just also be that will all the new parts on the engine, they just have not had time to break in yet? List of new parts:
-Connecting Rod Bearings, Wrist Pins, and Pistons
-Timing Chain and Cam Sprockets
-Machined Crank
-Cap and Rotor for the dizzy
-Plug Wires and Plugs
-O2 Sensor (Upper)

I know I have the timing set correctly, and followed FSM procedure to do so with the engine brought to TDC on cyl.1 (the yellow mark on the crank pulley), and the dizzy set with the rotor facing where the #1 plug wire goes, I unplugged the TPS sensor to begin setting the timing and set it at 20* BTDC and the mark will line up perfectly when the idle is at about 1500 RPM's.

I've pretty much run out of ideas, so any help would be greatly appreciated. Thanks in advance!

06-11-2015, 05:48 PM	#1
pignose.007 Join Date: Mar 2015 Location: Michigan Posts: 27 Trader Rating: (0) Feedback Score: 0 reviews	'94 KA24DE Running Super Rough Hey guys, I just finished building my KA and dropping it back into my car, and it will start and fire, but idle like absolute crap. When it idles, the engine will drop RPM's and eventually die over a period of about 45 seconds to a minute. When it is idling, the entire engine shakes quite a bit, and it also sounds like it is misfiring somewhere. I have a few variables on what it might be but any advice from you guys would be great. 1) I have a tiny crack in one of the vacuum lines that snakes through the intake, but I wouldn't really think it would cause the engine to run THAT badly. 2) I checked all the resistances for the fuel injectors and #'s 1,3 and 4 checked out with a 11.2 ohm resistance which from my understanding is within OEM specifacations. (11-14 ohms) #2, however put out a reading of 3.8 ohms, which leads me to believe that the fuel injector is bad. I back-probed all of the connectors, so I know that it is not a faulty wire or ground. 3) Could it just also be that will all the new parts on the engine, they just have not had time to break in yet? List of new parts: -Connecting Rod Bearings, Wrist Pins, and Pistons -Timing Chain and Cam Sprockets -Machined Crank -Cap and Rotor for the dizzy -Plug Wires and Plugs -O2 Sensor (Upper) I know I have the timing set correctly, and followed FSM procedure to do so with the engine brought to TDC on cyl.1 (the yellow mark on the crank pulley), and the dizzy set with the rotor facing where the #1 plug wire goes, I unplugged the TPS sensor to begin setting the timing and set it at 20* BTDC and the mark will line up perfectly when the idle is at about 1500 RPM's. I've pretty much run out of ideas, so any help would be greatly appreciated. Thanks in advance!