KA24DE missing at idle..

[MELLO*SOS]

For a while now my KA24DE has been missing at idle. Other symptoms include a frequent "stumble" (complete loss of power) at sub-3000 part throttle cruise/accel. At 3000+ rpm the car seems to run smoothly, although there is a noticeable loss of power from before and the exhaust smells horrible. Because of the miss the car will usually die at stoplights and pretty much anytime I ask it to idle for more than 15 seconds (without continually giving it a few revs to keep it alive).

I've...

-Replaced the plugs (What is the proper gap in mm for NA KA24DE?)
-Replaced the plug wires
-Cleaned the distributor cap contacts with emery paper
-Put in a new distributor rotor
-Tried adjusting timing (disconnected TPS) as close as I can but due to the miss it's almost impossible to make the car idle at 650rpm, making it hard to time.
-Pulled the codes, and (not) surprisingly there are none (55).

If I remove each wire individually (power balance test) the rpms will drop about equally on each cylinder. If I earth each removed plug it will fire with decent spark. I can't seem to track the miss to one specific cylinder, and all the plugs look the same.

At this point I think it's something to do with the ignition system, maybe the Coil or Distributor or wiring to them. How can I test the distributor and coil and the wiring to them from the ECU? Hoping a few of you have ran into this problem before. Any helpful suggestions are welcome, thanks in advance!

[Siizzzoooo]

I'm having similar problems with my Zenki

but it hasn't died on me yet.

car runs great cold, but after warms up, it doesn't feel as powerful. feels like
its lost 30hp.

It keeps throwing the engine coolant temp code, I've replaced it with a used piece, but still misses. Check engine light went away for about 500 miles, now its back on.

I've changed plugs and wires as well.

I'm going to the dealership tomorrow to get a brand new ECTS and hopefully that'll fix it

As far as gas mileage, i'm getting around 320-360 :/ (but I do start it up every morning at let it run about 10-15 minutes prior to driving :shruggs: )

[MELLO*SOS]

Thanks for the reply Siizzzoooo, sorry to hear that you're having similar problems.

Anyone else like to comment? I reset my timing to 20' BTDC last night and still have a persistant miss at idle... Any ignition troubleshooting tips would be appreciated.

[krustindumm]

ECTS's are a common failure on late 80's through mid 90's Nissans. If you can get a lab scope you can watch you're firing events and maybe figure out what is going on. From what you have replaced it may not be a ignition system failure though, maybe a fuel system cleaner & fuel filter would help.

Hard as fuck to diagnose stuff like this without having the car here where i can put the consult on it.

[MELLO*SOS]

I know! I am *this* close to buying consult type interface to check out the sensor outputs. I suspect it's bad wiring or a bad sensor. I have oscilliscope here at the office that I can borrow, what would I watch the input to the coil or the output from the distributor CAS, or... ?? Thanks for your reply. BTW I've ran some of the fuel injector cleaner stuff through with no luck. I have a new z32 fuel filter sitting at home, was going to wait until the RB goes in but might as well install it now.

[krustindumm]

hook the scope to the (primary, aka low voltage) negative terminal of the coil w/ the positive lead, and the negative lead to battery negative. That will let you see your firing and spark lines on all 4 cylinders. If you have an inductive pickup you can put on the cyl. 1 plug wire, you can use that for a trigger.

I'll have to scan in my old notes on what the firing and burn line should look like, but basically the firing line should hit at least 300V, and the burn time should be straight across but wavy, and at least 1mS long.

[MELLO*SOS]

Can someone please confirm the proper plug gap for KA24DE? Thanks

Edit: Looked it up in the FSM it's 1.0 - 1.1mm for KA24DE spark plug gap... I had mine set at 1mm already.

[1Via!]

Running good cold and running shitty when warmed up is a very common trait of a bad injector(s). How do your injectors sound?

It could be something totally different than injectors, but that is what popped into my head.

[MELLO*SOS]

Running good cold and running shitty when warmed up is a very common trait of a bad injector(s). How do your injectors sound?

It could be something totally different than injectors, but that is what popped into my head.

I listened to them with a screwdriver and they all sound fine, clicking away. I've also ran some of that techron injector cleaner through the fuel tank a couple tanks ago, I didn't see any change.

When I say it runs good cold, I mean for the first 10 seconds after you start the car. I think the Ecu goes into a startup mode and dumps more fuel and increases the revs to 1500 to warm things up. This mode only lasts 5-15 seconds depending on the temperature. As soon as this mode 'ends', the revs start to drop back to the normal 800ish and the motor starts to miss and it has a hard time holding a steady idle.

I'm replacing the fuel filter (to z32) and plugs (to NGK BKR5E11's) tonight, I hope that makes an improvement.. Installing my Walboro 255lph fuel pump last night made an incredible difference from 3000+ rpms, although it didn't change the poor idle at all.

[aaroneezee]

try to run some seafoam through the tank and through the motor. that really helped my car idle better and run a lot smoother.

[MELLO*SOS]

I've heard good things about that stuff. I've never seen it for sale in Wally world or Autozone, where can I buy it?

[MELLO*SOS]

Put in some NGK BKR5E11 spark plugs last night along with z32 fuel filter. I also cleaned the MAF with some carb cleaner. This really helped clean up the idle, it's a lot more stable now with very very little missing. Notice I didn't say it's 100% cured though.

[Siizzzoooo]

I plan on running seafoam this weekend and see if it'll clean up anything

[MELLO*SOS]

Damn it where can I buy that stuff at? :)

[rsxrcr87]

NAPA parts store

[s14xman]

my car is doing the same, from what i am reading it is the MAFS, mine is doing THE SAME EXACT thing!! i just ran seafoam and no luck, im 90% sure it has something to do with the MAFS. Did you guys solve your problem?? how??

Edit: just noticed my vacume line coming off my intake wasn't connected. Man do i feel like a dumb ass

[dct223]

i have similar problem... i miss at idle... ive changed... plugs, wires, o2 sensor, mafs, valve cover gasket and spark plug gasket, cleaned TB, z32 fuel filter, new cap and rotor... you name it... Although my car now runs better when i drive... i still miss... The only thing i havent done is changed my injectors... I think my injectors are leaky i get fuel trim code and #1 cylinder misfire from time to time so hopfully thats the problem... Im proll gonna swap out injectors with my friends spares over spring break and hopfully that will solve my problem... if not... i give up.... say fuck it and go SR or something..

['90RPS13]

Sizzo or Mello, did you guys ever solve this problem?

[MELLO*SOS]

This specific issue, yeah. The car has been running great for the last year or so. Somewhere along the way replacing the fuel pump, fuel filter, spark plugs, plug wires, cap, rotor and cleaning the MAF the miss at idle problem went away. Try inspecting or replacing any of that stuff and see where it leads you, the missing is usually a bad spark or a bad injector.

I just replaced a bad injector last sunday, so maybe those were symptoms of a bad injector a year in advance who knows...

[contranication]

The plug gap for ka is .043 inches... which is 1.09 mm on a conversion calculator

[NINJASPY]

lol fuck i bumped wrong thread... sorry.

[iceman1981]

I had the same problem i changed my coolant temperature sensor and mines doing fine