Random misfire/bogging

[LA_phantom_240]

My KA s14 just started a new thing today (our one year anniversary) while I was driving on the interstate. Typically, the car is driven in city traffic only, with only a couple trips on the highway a week, usually less than an hour long. Today I needed to go to Alabama to drop parts off for work, and was about two and a half hours one way. Well, about an hour and a half into the trip, I'm going about 75 and I get a random bog/bucking less than a second long... like maybe one or two cylinders misfiring. Didn't think much of it, dropped off the parts, and started to head back. About 15 minutes later, I get the same half-second bog. From then on I got it once maybe every 30 minutes or so. One of the little spazzes lasted almost a full second and had me kinda worried. She made it home, and coming off a light, I went through first, and at about 3500rpm (just before I shifted), it bogged out for almost a second. When I got home, I popped the hood and listened to her idle, listened to the exhaust, looked for anything obviously loose, but I came up with nothing. I have an existing CEL regarding my lack of EGR valve, so I don't know if any new codes are up yet until I pull them tonight or tomorrow.

Here's the car's history.
Bought the car a year ago today, and had a stock KA which had supposedly 90k on it from another s14, had 138k on the body. About 6 months later, I had a problem with my fan controller during the winter that caused it to heat up BAD. Car didn't have any of the typical systems of head/headgasket damage, so I didn't pay it much mind. Until that the clock hit 158k miles, I noticed it was a little sluggish, and noticed bubbles in my coolant, and found another motor. Did a tuneup, cause it was due, and decided to replace the fuel filter as well. Turns out the fuel filter was the ORIGINAL filter, complete with OEM numbers still on it, and the hose would NOT come off, and it was stopped up as HELL. Replaced it with new hose (fuel injection hose), and a Z32 filter. At 163k, I pulled the motor and put in an s13 KA from a wrecked 91 with 80someodd thousand miles on the clock. Used my intake, distributor, etc. Car has a K&N drop in filter, altima fans, ASP crank pulley, DC header, XSPower exhaust (I know, I know... it was free though), and that's about it under the hood. Basics. New cap, wires, rotor, plugs, when I swapped the motor, and its sitting at 165k miles.

I'm thinking maybe the coil in the distributor is starting to get weak when its hot, or something else stupid like that and spark related.

[LA_phantom_240]

Wow. No replies. That's lame.

[nismoskyz]

dude my S13 KA bogs and often misfires at the same rpm range. i havent been able to fully get rid of it yet, and sometimes it disappears all on its own, but only for a few minutes.. and I also have that same CEL for EGR, code 32 .. i am still, however, waiting to replace my spark plug wires and am dearly hoping that that will solve the problem once and for all..

you seem to have taken care of pretty much everything i can think of except the mass air flow sensor. since you've got some old parts in there, it's possible that maf just happened to get too dirty at this point.. see if you can purchase some "CRC Mass Air Flow Cleaner" from your local auto parts store, that stuff really made a noticeable improvement to my KA, although it did not rid it of the bogging entirely.

that's pretty much all I can suggest, good luck man.

---lol, nice tags for the thread... i feel your pain.

[LA_phantom_240]

Originally Posted by nismoskyz

dude my S13 KA bogs and often misfires at the same rpm range. i havent been able to fully get rid of it yet, and sometimes it disappears all on its own, but only for a few minutes.. and I also have that same CEL for EGR, code 32 .. i am still, however, waiting to replace my spark plug wires and am dearly hoping that that will solve the problem once and for all..

you seem to have taken care of pretty much everything i can think of except the mass air flow sensor. since you've got some old parts in there, it's possible that maf just happened to get too dirty at this point.. see if you can purchase some "CRC Mass Air Flow Cleaner" from your local auto parts store, that stuff really made a noticeable improvement to my KA, although it did not rid it of the bogging entirely.

that's pretty much all I can suggest, good luck man.

---lol, nice tags for the thread... i feel your pain.

The MAF was cleaned at like 158k miles, along with the IAT sensor.

S14's are such an enigma at times.

[240s4life]

sounds to me like the coil in the dizzy.
If it gets weak it won't produce as hot of a spark and won't fully ignite the fuel.
Had a similar problem in my pick up truck and it ended up being the coil.

Oh the internal coil in our distributors..

[LA_phantom_240]

Oh the stupidity. I wonder if anyone has ever done a s13 dizzy conversion on an s14? lol. MSD blaster coil is difinitely ftw.

Oh well. I guess I'll hunt down another dizzy and get better spark plugs... the ones in there are kinda cheap, but platinum, like the factory

[SlideWell]

carbon build up in the evap system? my old s14 kouki had 64k miles and it started bogging. i drove it hard more often and it never bogged again

[LA_phantom_240]

Evap system was removed.

I went to AutoZone and scanned the codes with their scanner. Mind you, some say my s14 (built 3/94) should be OBDI, others say all are OBDII, some say depending on where it was built, etc. Anyway, the scanner turns on when you plug it in with the key off, like an OBDII car, so I rolled with it. I got 3 codes.

-EGR Solenoid malfunction. The EGR was removed, so yeah I'm gonna get that code til I fool the ECU.
-Knock sensor malfunction. I dunno if the sensor went out or not, but I have one off my old motor, so I'm gonna change it and try it out.
-O2 sensor malfunction, bank 1 sensor 2, A.K.A. rear O2 sensor. The sensor is maybe a year old, so I wouldn't figure that its bad. Of course, running with a DC header, I have no cat, so that may be setting off the code.

In any case, the suggestions the computer gives is that the car could be running rich or lean and causing a misfire. Both say at the bottom that low fuel pressure could be the problem. This sounds logical to me in some aspects, except for the bogging/cutting out is random and not really a long thing... a second at the most. I would figure rich or lean would be pretty constant, unless my fuel pressure regulator is going out or something. It is also saying an engine misfire can also set of either of these codes. I'm thinking "DUH", cause its definitely having a misfire randomly.

How would I go about checking my fuel pressure coming off the filter? Or test if my regulator is working?

Or are these codes being thrown cause of some other system giving an incorrect reading making some sort of compound clusterfuck problem?

[LA_phantom_240]

Nothing?

Lame.

[flclsteve]

u know i have a similar problem kinda like im on the gas and it just kinda jerks and feels like theres no power for a sec then goes back to normal usually when it happens for that split 2nd i just give it more gas and its fine but yea its annoying

[LA_phantom_240]

I had a bunch of codes, but I can't find what I wrote em down on. I know I had a 105 for sure, which is EGR related, which i don't have lol.

[Bigsyke]

The EGR will set off the KS code. If you removed the EGR system, most of the time you will get that KS code, and it will retard the timing to around 15*.

My only oppinion is to reinstall the EGR, unless somebody knows how to compensate for the extra timing being pulled because of lack of EGR.

and yes some s14's like mine are OBD1

[LA_phantom_240]

Well tonight I ran my codes again. I got 105, for the EGR, and then I got code 12, the MAF, which worries me cause I've never gotten that before. Gay.

Someone told me that the computer throwing out random codes may mean the computer is going out...

[LA_phantom_240]

I also notice that once I clear the codes, she runs fantastic for a while, then starts to run shitty and then, BAM! Check engine light. With the light on, it runs consistantly shitty.

[Bigsyke]

make sure the MAF connections are tight;

Are you using 91-92 octane? might throw a KS code if you use anything below that, but NO cel will be thrown. Check CTS

[LA_phantom_240]

I always run 93 octane. How do I check my CTS?


The MAF code is what makes me really worried.

[Drifterxxl180]

Ok as of reading your problem I've had them same thing happen to me about 3 weeks ago. The scanner that I used was the Snap On Modis and it as well said Maf so thinking that it was the maf I bought a new one which did not fix the problem. After looking into it further I found that around my intake manifold that I was sucking in air after the maf, depending how much is be sucked it will cause you car not to idle, hesitation, poor fuel mileage.

How ever there are TSB's out for the ECM on this year along with and Crank sensor see if links works and follow that procedure before replaceing things.
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[Drifterxxl180]

One other thing to try is a power balance test to figure out which cylinder is misfiring.

to do this start the car and one at a time pull off the plug to the injector and if rpm drops then that cylinder is good now if you pull one off and no rpm drop then that cylinder has a problem

[LA_phantom_240]

Its not a constant misfire. Its more like I'll be driving and all of a sudden every cylinder shuts down for a second. The exhaust goes all quiet, the car does a nose dive... its bad.

[krislin]

Dunno if you've fixed it yet, but your throttle position sensor dying can cause the same problem. I've got a SR, but run across similar symptoms several times. TPS, MAFS, intake leak, and I've cracked a few spark plugs, all caused the same stuff. I'd start with the TPS tho.

Just an idea.

[LA_phantom_240]

I never fixed it. Problem went away for quite some time and sometimes it just randomly fucks off. I don't care anymore though cause 1) I bought another S14 (needs front end body panels), so my current S14 is getting sacrificed. 2) I'm going RB25, so as long as my KA gets me where I need in the meantime, I'm good.

[krislin]

Yeah, fair enuff. I've been dealing with idle issues for as long as I've had my sr20...doesn't seem to want to be fixed. Trying something new tomorrow. Again.

[BigVinnie]

Originally Posted by LA_phantom_240

Evap system was removed.



-EGR Solenoid malfunction. The EGR was removed, so yeah I'm gonna get that code til I fool the ECU.



-O2 sensor malfunction, bank 1 sensor 2, A.K.A. rear O2 sensor. The sensor is maybe a year old, so I wouldn't figure that its bad. Of course, running with a DC header, I have no cat, so that may be setting off the code.

If your engine uses an EGR temp sensor, that along with the upstream O2 sensor would cause bogging and misfire. I don't believe the knock sensor would cause that problem for you.

[LA_phantom_240]

Originally Posted by BigVinnie

If your engine uses an EGR temp sensor, that along with the upstream O2 sensor would cause bogging and misfire. I don't believe the knock sensor would cause that problem for you.

I don't believe my car came with California emissions, so that's a negative good buddy.

[bbejj123]

does it feel like a fuel cut out? like is there something in the fuel filter?

[LA_phantom_240]

Originally Posted by bbejj123

does it feel like a fuel cut out? like is there something in the fuel filter?

It feels as if I just shut the car off for a split second... but the fuel filter only has like 7k miles on it, and its a Z32.

[xsparc]

No i didnt read all the posts, just the first one. But...

This sounds like a bad knock sensor.... well at least thats what it was on mine, when it would bog at around 3-3.5k. It ended up being the wire going the the sensor was grounding out, not the sensor itself.

[LA_phantom_240]

Originally Posted by xsparc

No i didnt read all the posts, just the first one. But...

This sounds like a bad knock sensor.... well at least thats what it was on mine, when it would bog at around 3-3.5k. It ended up being the wire going the the sensor was grounding out, not the sensor itself.

Ya know, I hear all this about the knock sensor wire grounding out... but I never see any kind of pics to help me find what wire to look for. Mind you, the knock sensor is a pain in the dick to get to, so I'm not really gonna poke around too much.

[Bigsyke]

You either half assed emissions removal, and you need to unplug the KS subharness, and insert a resistor into the female side of the engine harness. Also place a resistor on the EGR temp sensor.

Putting a resistor on the KS is just about the easiest thing you could possibly do, its one of the most exposed harnesses.

[LA_phantom_240]

Originally Posted by Bigsyke

You either half assed emissions removal, and you need to unplug the KS subharness, and insert a resistor into the female side of the engine harness. Also place a resistor on the EGR temp sensor.

Putting a resistor on the KS is just about the easiest thing you could possibly do, its one of the most exposed harnesses.

Which sensor is the EGR temp sensor? I don't recall ever seeing one... and I tried searching a while back for what resistance value to use for the knock sensor, but everything I came up with was detrimental to the car's driveability.