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View Full Version : Misfire and rough idle. Help!?!?


JettNebulis
06-22-2017, 02:18 AM
Alright I will first start with saying sorry for spamming the community with my bucket 240sx.

This is my Magnum Opus

Skip to the bottom if you don't want to read my story and jump right to the issue.

So will start with saying how this started with my driving :2f2f: late at night despite my slipping clutch I was having fun all of a sudden my engine seized and here I am waiting at 2 in the morning for AAA on a freezing february night. That night I pieced together a rebuild kit and a week later got to work. I noticed that I had a bit of wear on my crank shaft and sent it off to have it machined. It came back finished my rebuild according to fsm and it said to tighten idler sprocket to 140 foot pounds (or something like that) needless to say that was way too much for a used 240 head it stripped it. I later found out that it was 80 foot pounds tried to helicoil it and it didn't work. So I had my original blown motor in the back from when I bought it pulled the head off and cleaned it and installed it. That's when my frankenstein motor was built and after a month of trying to get it to work I realized it was a lost cause and yanked it out. A waste of 2 months :picardfp:

I bought a reman engine all new I installed it started it up and had a bad idle started replacing stuff and this is where im at. cylinder 2 is getting weak spark im pretty sure. I will now go through the list of stuff i've replace and their effect.

Spark plugs - no change

Wires - no change

FPR - made a big difference cut the shaking in half

Cap - no change

rotor- no change

distributor - no change

Tps - leveled out idle, however it was still rough

maf - made the shaking better but nothing extreme

air filter - no change

injectors - are fairly new, but I found some altima injectors and flipped them around no change. I know im getting fuel to the second cylinder.

Ignitor coil - no change

temp sensors - fairly new if I unplug them I notice a change in idle

fuel pump - fairly new it's a 255 LHR getting good pressure

battery - new tested good

terminals - replaced yesterday

o2 sensor - is new

Grounds - I cleaned and resurfaced the two grounds behind the engine. Replaced the ground connector coming off the harness near the injectors.

fuel filters- was used for around a month.

injector o-rings- no difference.

I think that's about it right now there is bad spark to cylinder two that only affects the engine till around 3k then it just feels a little under powered.

I am replacing the ECU, fuel rail, and maybe the maf again tomorrow.

This is my last plea for help. Thank you Zilvia now fix my ride. :snoop:

jedi03
06-22-2017, 07:54 AM
disregard...is there a voltage regulator on the ka? its been a while since I used an NA motor

JettNebulis
06-22-2017, 08:09 PM
disregard...is there a voltage regulator on the ka? its been a while since I used an NA motor

Not that I know of. Where would it be located at.