KA24DE misfiring on and off

[Nashville91s13]

Ok so my 91 240 with stock motor is misfiring on and off. Sometimes when I drive it it will run fine...sometimes the front cyl won't fire and it runs like a**. What could be causing this intermittent problem? It has new NGK's in it as of yesterday. 101,500 miles

[Koshin]

did you check the usual suspects first? loose spark plug wires? distibutor? engine grounds?

[NISSAN240SX12]

check your spark plug wires for any cracks. it could be arcing.

[Nashville91s13]

It's been dark when I've been looking at it. I'll have to inspect the wires during the day, but yea I made sure they were seated right on the plugs and the distributor. I really want to catch it doing it and see if the wire will fire on a ground. It fires consistently when it's running right.

[youngun21a]

I had a misfire for about two weeks and today i just fix it and it was my spark plug wire on cyl3..did all the usual suspects..new spark plugs,,new cap and rotor,new coolant sensor,o2 sensor and the weird thing is that the spark plug wires where new too..so i was scraching my head left and right trying to figure out what was wrong..So I did my timing and it was good so before i wanted to give up and take it to a mechanic..i took my spark plugs out and lined them up and the spark plug number 3 was diffrent then all the rest..so there you go bad sparkplug wire and no backfire

[Nashville91s13]

I had a misfire for about two weeks and today i just fix it and it was my spark plug wire on cyl3..did all the usual suspects..new spark plugs,,new cap and rotor,new coolant sensor,o2 sensor and the weird thing is that the spark plug wires where new too..so i was scraching my head left and right trying to figure out what was wrong..So I did my timing and it was good so before i wanted to give up and take it to a mechanic..i took my spark plugs out and lined them up and the spark plug number 3 was diffrent then all the rest..so there you go bad sparkplug wire and no backfire

So spark plug 3 was different....different how? I don't know how a bad wire would work fine sometimes and cause a misfire sometimes. You would think that if it's bad it would misfire ALL the time.

[NISSAN240SX12]

it works like that were it would work one min and the next no good. night time would be the best time to check the wires so you could actually see the arcing. i would just wiggle the wires around from end to end. doesn't hurt to check out. i had a random misfire and it turned out to be wires.....

[youngun21a]

It was darker then the rest..the fuel was not being burnt completely and the rest where lighter so when i pulled the sparkplug wire and removed it from the plastic case it was just dagling there so i cut it and put it back bam no more backfire when i stomp on the gas..(( yeah mine did that too it would work fine after awhile or if i was at a constant speed i would feel it hesitate or like it skip a bit..and if i was at a stop light my rpms would drop for a sec and go back to normal...and i had to give it gas for it to go away..

[Chris28]

Replace the plug wires the report back.

[Nashville91s13]

Replace the plug wires the report back.

I'll wiggle and bend the wire up and down the length of the wire and try to make it misfire. Hopefully that will work and I'll know it's just a wire and I'll buy a good set of NGKs and be done with it. Any wire suggestions are welcome.

[Nashville91s13]

Alright so I replaced the wires so now it has new wires and plugs. It didn't miss on the way home, we'll see. I have to drive to work (15 min) this morning and to Clarksville (45 min) this afternoon. I'll report back. Thanks

[Nashville91s13]

Well it's been a week and no more misfiring. What is the normal idle for an auto in gear? Feels a little low..but again I've never owned a 4-banger before. Idle in gear for me is just above 500rpm.

[NISSAN240SX12]

my KA idles at about 550 RPM's.

[Nashville91s13]

my KA idles at about 550 RPM's.

Ok then that should be right then I guess.

[24j0hn]

in my opinion, since you already did half a tune up, why not just buy a new cap and rotor also?

that way you wont have to worry about it later...

[Nashville91s13]

Yep...that will happen, but it's running fine as of now. I'll buy one soon when I get more money. I'm a college student and I work one day a week so things will slowly come till summer hits and I can work work work. I also ran some Lucas fuel injector through it will a full tank a few days ago.

[24j0hn]

Yep...that will happen, but it's running fine as of now. I'll buy one soon when I get more money. I'm a college student and I work one day a week so things will slowly come till summer hits and I can work work work. I also ran some Lucas fuel injector through it will a full tank a few days ago.

nissan gave out a TSB about using fuel injector cleaner in the fuel tank... it may clean the injectors to some benefit, but it can also cause corrosion in the injector and lead to failure... if your gunna clean injectors clean them manually by taking them out and spraying carb and choke cleaner into the metal filter on the injector...

or just simply use higher end gas like shell and chevron... and run at least 89 octane...

[Nashville91s13]

nissan gave out a TSB about using fuel injector cleaner in the fuel tank... it may clean the injectors to some benefit, but it can also cause corrosion in the injector and lead to failure... if your gunna clean injectors clean them manually by taking them out and spraying carb and choke cleaner into the metal filter on the injector...

or just simply use higher end gas like shell and chevron... and run at least 89 octane...

Well thanks for that info! I won't use it again then. That's good to know. I use Shell premium gas only

[Dattebayo]

Stock idle for an automatic is 800RPMManual is 550-700.

Octane doesn't matter about missing.How do you know that the front cylinder is the one that was missing?Are you psychic?Did you pull the plug and smell for fuel?Did you even check the injector if you did the previous step?Did you check the spark plug to see it was firing by disconnecting all the other wires and hitting the ignition?Did you check the gap on your plugs?

[Nashville91s13]

Stock idle for an automatic is 800RPMManual is 550-700.

Octane doesn't matter about missing.How do you know that the front cylinder is the one that was missing?Are you psychic?Did you pull the plug and smell for fuel?Did you even check the injector if you did the previous step?Did you check the spark plug to see it was firing by disconnecting all the other wires and hitting the ignition?Did you check the gap on your plugs?

Duh octane doesn't matter about missing...it just runs better and premium is recommended.Simple genius....pull each plug wire individually while it is missing and see which one does not cause a difference.I pulled all the plugs and they were pretty much shot....and way out of gap...so I gaped the shi**y plugs and got new NGKs and gaped them and swapped for the new ones.It missed again one day so I replaced the wires. *NO MORE MISSING*

[youngun21a]

Glad you got it fix..Mine purrss at 650rpms and only use 93 octance and nothing less..since i got it 4 years ago and 3 full rebuilds

[Nashville91s13]

Glad you got it fix..Mine purrss at 650rpms and only use 93 octance and nothing less..since i got it 4 years ago and 3 full rebuilds

Dang...why so many rebuilds?????

[24j0hn]

Well thanks for that info! I won't use it again then. That's good to know. I use Shell premium gas only

im a shell guy too!... no problem:)

[youngun21a]

First rebuild when bought 180000miles,with oem parts,second rebuild heater core line busted ,temp gauge lock on the normal temp only warning was the white smoke behind me..pulled over and it was over..third rebuild semi-oem parts CP pistons,eagle rods.stage two crower cams,super tech vavles but no arp bolts ran great for a year and a half,then on this september head gasket pop, rebuild head and block no damage..and now running super.

[Dattebayo]

Duh octane doesn't matter about missing...it just runs better and premium is recommended.

It doesn't make a difference except running a little cooler with high octane, not with your stock internals. Your engine is actually tuned to run 91 octane. Chalk it up to a few years experience.

pull each plug wire individually while it is missing and see which one does not cause a difference.

This doesn't work. If you pull the plug wire on cylinder #2 or #3, you may not notice any difference anyway because how the crank is balanced.

Hey, I'm just trying to be thorough and helpful. Alot of the advice you get on this forum is whack.

[Nashville91s13]

It doesn't make a difference except running a little cooler with high octane, not with your stock internals. Your engine is actually tuned to run 91 octane. Chalk it up to a few years experience.

This doesn't work. If you pull the plug wire on cylinder #2 or #3, you may not notice any difference anyway because how the crank is balanced.

Hey, I'm just trying to be thorough and helpful. Alot of the advice you get on this forum is whack.

Well it ran like crap when 1 was pulled and then the plug smelled like gas...but anywho.....it runs fine now with plugs and wires. Any tips for a new clueless KA24DE owner are greatly appreciated. (do's and don'ts) I'm not really familiar with any tendencies of this motor or the car. It's seems to be fine with 101k on it except for I think the oil fill cap has a small leak even though I cleaned the seal and tightened it down. There is also a tiny oil leak at the right little plastic half circle piece in front of the cam gear. The car is 1000% stock as of now.

[Nashville91s13]

First rebuild when bought 180000miles,with oem parts,second rebuild heater core line busted ,temp gauge lock on the normal temp only warning was the white smoke behind me..pulled over and it was over..third rebuild semi-oem parts CP pistons,eagle rods.stage two crower cams,super tech vavles but no arp bolts ran great for a year and a half,then on this september head gasket pop, rebuild head and block no damage..and now running super.

Did you run higher compression pistons with stock head studs and that's what caused the head gasket to pop?

[Dattebayo]

First rebuild when bought 180000miles,with oem parts,second rebuild heater core line busted ,temp gauge lock on the normal temp only warning was the white smoke behind me..pulled over and it was over..third rebuild semi-oem parts CP pistons,eagle rods.stage two crower cams,super tech vavles but no arp bolts ran great for a year and a half,then on this september head gasket pop, rebuild head and block no damage..and now running super.

240 owners: Always cheaping out somewhere.

[youngun21a]

Nope there 9.0:1 compression only thing that I cheap out was on the arp headbolts,but don't think it would make a diffrence since i'm not running boost..

[DamonDread]

in my opinion, since you already did half a tune up, why not just buy a new cap and rotor also?

that way you wont have to worry about it later...

DittoI have never changed spark plugs with out changing at least wires along with it. Most ppl who change plugs/wires dont grease the boot that fits over the spark plug and ends up killing the connection when you pull it off to check or change. The wires could have been fine right b4 you took them off to change the plugs. Just my .02. I always, always do both at the same time. And grease the boots.