Annoying miss/stumble going into boost?

[hydra]

Hey All,First off let me mention that I've got a BONE STOCK, and I really mean BONE STOCK '92 S13 200SX with CA18DET engine which was running perfectly fine until a couple of days ago, when it developed this odd hesitation/miss/stumble going into boost combined with somewhat reduced power at higher rpm (above 4k) The car idles perfectly normally, and seems to behave normally up until 2000-2500rpm or so at which point it starts hiccuping somewhat at anything above 20% throttle up until 4000rpm at which point the problem isn't as marked, but I can feel that power is reduced above that. My gut instinct tells me its one of the following:

- Boost leak? I checked for loose IC-piping hose clamps but couldn't find anything obvious, will conduct a more thorough investigation tomorrow at the shop...

- Loose Knock Sensor connection? This is a wild-a** guess, but it "feels" as though the ECU intermittently pulls back a bunch of timing, back and forth,

- Coil occassionally misfiring? I doubt it since the idle is rock steady but what the hell...

I should add that since my plugs are standard heat range NGK Iridium plugs and appeared to be in decent condition when I checked them two weeks ago... I'd really appreciate your input on this, thanks!

[ca18detgabby]

coil



tell tail signs....... unclip each one(on at a time)...... if the cars run conditions dont get worse by unplugging, that is the bad coil.

should change the plugs well you are at it

[sjbsuperman1425]

coil



tell tail signs....... unclip each one(on at a time)...... if the cars run conditions dont get worse by unplugging, that is the bad coil.

should change the plugs well you are at it

it sucks those coils are so much..especially if you have all four go out at the same time lol atleast we can pick them up at the local parts store though...

[blacksrjdm]

it sucks those coils are so much..especially if you have all four go out at the same time lol atleast we can pick them up at the local parts store though...

What use was this????

[r34 gtr]

What use was this????

And what use was this?

He did inform him that the coils could be be bought at your local parts store. Go back to your JDM tyte SR forum.

[blacksrjdm]

This is helping.....

Knock sensor code is normally a dummy code for another problem. If you have a misfire, that is probably causing the knock sensor code, which in turn may be causing it to pull out a slight bit of timing. Is a common problem and code for all Nissans. It senses a vibration at one time and leaves the code to be found later. Allows the technician to diagnose the problem easier. Yes you can buy those coils from any parts store, though you would have found that out when you go to buy it. Best way to check a leak in the piping is with a smoke tester if you have one available. Fills up the pipes with harmless smoke and watch where it puffs out. Good luck and have fun with it.

I suppose I'll go back to my JDM TYTE sr forum now that I'm through here.

[Ca_Silvia]

I think you are very very wrong about the knock sensor. When my knock sensor started f***in up, my car barely drove over 4000rpm. When the coils go all it does is trip a misfire code.

There is no mass Nissan cover up for misfires/knock sensors problems

[hydra]

Just for the record, my problem is intermittent... 20 min into a 30min drive it just went away of its own accord. It came back briefly on my way back home later in the evening and then vanished again! Once again my idle is perfectly fine, and the car fires up right away much like it always has...

[blacksrjdm]

I think you are very very wrong about the knock sensor. When my knock sensor started f***in up, my car barely drove over 4000rpm. When the coils go all it does is trip a misfire code.

There is no mass Nissan cover up for misfires/knock sensors problems

This is how Nissan describes the Knock Sensor.

The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. The pressure is converted into a voltage signal and sent to the ECM. That is from a Nissan Dealership Assist program that the techs use here at the Nissan dealer I work for.

It also explains on this bulletin that if you have a drivability problem such as a coil or injector, or even an O2 sensor, and you have retrieved a knock sensor code from the ECU, then start with the drivablility problem, then if that doesnt fix the knock code then the sensor has high or low voltage (which would also pop up a code that would say knock sensor High/low voltage) and the sensor has either shorted or has an open circuit. Which then, replacing the sensor would be ness. but only if the code is read "knock sensor circuit high/low voltage" should the knock sensor be replaced or check the wires to it.

I work at a Nissan Dealership, in the parts department and see this happen 3-4 times a day. We NEVER replace the knock sensor, and I have saved a few local shops some aggrivation from having to changing them, in some of the new pathfinders, they are under the plenum/intake.

Wouldnt have said it if I didnt know it to be true and see it every day. But, no one ever agrees with me so...

[ca18detgabby]

it sucks those coils are so much..especially if you have all four go out at the same time lol atleast we can pick them up at the local parts store though...

so much? they are so easy to pick up..........least they used to be. I have 4 complete spare sets just in case I ever need them.

[Nali]

so much? they are so easy to pick up..........least they used to be. I have 4 complete spare sets just in case I ever need them.

QFT!.You can get brand new coils at Autozone or any autoparts store really, for relatively cheap.....

To OP, i had a similar problem a number of times. First time i ask, everyone told me coilpacks so i changed those out for Autozone ones, and yup problem disappeared. Second time the problem showed its ugly head, i knew it wasnt the coils again because i got like 4 sets of coils which i used to check. This time it was the MAFS that was dirty.

My euro car had the same problem and i thought it was coil packs again, changed them out, but didnt help at all. So i did some trouble shooting, and it ended up being the fuel pump about to die on me. Got a new pump and the 200sx run perfect.

[hydra]

Is there a specific procedure to test each individual coil (i.e. measuring coil resistance?) to know which coil/coils are giving me grief?

[blacksrjdm]

I think someone already told you how to diagnose coils. While running unplug each coil, and see if there is a change. If it stumbles worse when you unplug a coil then you know that that coil is good. If you see or feel no change when you unplug a coil then that coil is not firing.

I would go ahead and change the spark plugs too. Could just be a fouled plug.

[float_6969]

You guys aren't reading his posts at all are you? He said the problem is intermittent and the car idles fine. Unplugging coils isn't going to help him find the problem.

OP, if you haven't DL'd the FSM from the FAQ yet, do so and then look through the EF & EC section. The procedure to check the coils is in there.

Also, I would like to see you pull the codes from the ECU as well.