vtec effect in a ka?

[h22speed]

so i have noticed lately that there has been a power loss in the sub 5k rpm range, but past 5k i guess when the ecu stops pulling timing i get full power restored and jerks almost like a vtec. i want my low end back and need someone to tell me how to fix this annoying problem or at least where to look. i have searched, but im sure a pro at google could do it better... pls help. i guess it has to do with the knock sensor or the wiring but would like an expert opinion and steps to fix it

[codunc]

do you have a check engine light on? have you done a compression test?

[h22speed]

compression is perfect, no check engine light on. pulled the codes awhile back and it wasnt giving me the knock sensor code. anyone else have this happening?

[MunsonAuto]

Basic tune up maybe? plugs and wires? IDK, just a thought...

[The Chad]

Please figure this out for me hahah. I had this on my old S14. I wrecked that one and on my new S14 of the same year 95', was just fine. I even dynoed the old car and pulled 127 hp till 4600k, then jumped to 140hp....and I mean JUMPED...fricken weird man.

I know I didn't help, but I hope you do find an answer. :)

[h22speed]

Basic tune up maybe? plugs and wires? IDK, just a thought...
plugs wires all that crap is new... less than 3 months aold as are all of the injectors

[sunnys14]

Knock sensor is bad, change it or check the wiring going to it.

[UNISA JECS]

Knock sensor shielded wire is most likely shorted to ground, trace the entire lenght or replace teh wire from ECU to knock sensor.

[HS13KLS]

Knock sensor shielded wire is most likely shorted to ground, trace the entire lenght or replace teh wire from ECU to knock sensor.


beat me too it.

that seems really odd though :/

[UNISA JECS]

I have fixed 10 S13's to date and every single one had the error code 34 (knock sensor) and had a short to ground in the shieled singal wire, this error code is NEVER illuminated alone, most people only become aware of the problem when they throw another code with it that does illuminate the check engine light.

Symptons:
Vtec effect around 5,200rpm
Bad gas milage
Sluggish performace

Have fun finding the short.

p.s. None of the 10 S13's I've fixed needed a new knock sensor, even the knock sensors that had stress cracks were bad, it was all in the signal wire.

[zugoi]

Imma just cut the knock sensor wire completely so i hit vtec sooner :keke:

[UNISA JECS]

Just buy a Apexi VAFC and adjust it to come on right off idle, you'll be dope!

[kcvpr]

Just buy a Apexi VAFC and adjust it to come on right off idle, you'll be dope!I think i may have this problem on my 13, do you think you could explain in detail what needs to be replaced and how to do it? or atleast a link to a faq? thanks!!!!

Ill search for a solution in the mean time as well.

[UNISA JECS]

I've posted here:

Just a bunch of related shit

Knock Sensor Junk! - SR20 Forum (http://www.sr20forum.com/general-sr20/213046-knock-sensor-junk.html)

http://zilvia.net/f/tech-talk/202768-code-34-knock-sensor.html

http://zilvia.net/f/tech-talk/166567-cracked-knock-sensor.html

http://zilvia.net/f/tech-talk/154714-knock-sensor-help.html

http://www.zilvia.net/f/tech-talk/137317-damn-ka-bogging.html

Knock sensor code 34. - SR20 Community Forum - The Dash (http://www.sr20-forum.com/turbo/8305-knock-sensor-code-34-a.html)

http://zilvia.net/f/tech-talk/197921-ka24de-n-dyno.html

[lflkajfj12123]

good to know

looks like i'll be checking this too when i do a tuneup

[UNISA JECS]

For refference this is what the cable in question looks like:

UL 1533 Cable (single conductor)
http://i167.photobucket.com/albums/u159/zilvia_album/SP32-20090125-104722.gif

This is what happens in all teh cases I have fixed, the "conductor" and the "spiral shielded" shorted threw the "PVC-Insulation"

[h22speed]

thanks alot unisa.. gonna give it a look over next weekend

[UNISA JECS]

BUMP does anyone know where I could buy some UL 1533 cables, its hard to find any place but china in bulk...

[h22speed]

i havent searched but if u find some let me know... i fixed what looked like you are talking about on my car but i think i just need to replace the entire wire. it now does it intermittently, so im not sure if that means there is a problem with the sensor itself but im gonna have to spend more time on this one unless anyone knows why it would do it sometimes and other times not.

[UNISA JECS]

i havent searched but if u find some let me know... i fixed what looked like you are talking about on my car but i think i just need to replace the entire wire. it now does it intermittently, so im not sure if that means there is a problem with the sensor itself but im gonna have to spend more time on this one unless anyone knows why it would do it sometimes and other times not.

Most likely because you have more than one break in the signal wire I encountered this before, the reason im asking if anyone has found a local source for the wire is because I have a car right now that has more than one break and is also getting intermitten knock sensor error codes and it is not sensor related.

[UNISA JECS]

qqqqqqqqqqqqqqqqqqqqqqqqqq

[hondanissan]

this may be the case on my car as well. i have a 95' and no matter how much i try to get the car back on stock timing...its set on stock timing (physically looking) and the timing gun is reading way off the mark...and i have done all the neccesary sprocket, pulley, tdc, etc and it still runs crappy from below 3grand. And you guys say that code 34 can affect timing. I'm going to check this out.

[UNISA JECS]

Oh yea thanks hondanissan just reminded me of somehting I wanted to share with you all, when you car does have the knock sensor issues you can set your timing still with a gun to 20*degree like normal but after your done setting base timing and all your car will command ~10*degree timing +/- 1*degree timing.

[s13pignose]

Funny this thread should get bumped. my car has for about 1-2 months now having sudden jerks like the car is gonna die, but usually doesn't. Maybe once or twice it has. Only code I ever got since is 34. I've changed fuel filter not long ago, and manage to keep the 34 away for about a week. Then it came back and left for about another week lol. Well changed my valve cover gasket recently and took timing chain guide off (upper..vey top one). Car did the jerk thing again next day. Also it feels SLOW..even for an automatic.

So pulled ecu and got code 34, and no matter how many times I reset and start it WOULD NOT leave. Never had a code 55 (ok)

[UNISA JECS]

ANOTHER THING I WANNA STRESS CODE 34 (KNOCK SENSOR) DOESN'T AND NEVER WILL ILLUMINATE THE CHECK ENGINE LIGHT, ONLY IF ITS ACCOMPANIED BY ANOTHER CODE THAT DOES.

Also like s13pignose described and instantaneous code 34 means a diffenant wiring issue.

[s13pignose]

Yeah not lying about that..never ever got one..only me knowing my car not running right. You definitely feel slower..my car even sounds quieter than norm too.

I was hoping mine was just sensor, but your thinking wiring...shoot! Also when car feels like its gonna die I hear the relays near the ecu click. Weird thing is I've had it do that with the jerk, and have no code when I get home and pull ecu???

[Bigsyke]

I breezed through most of the BS;

KS code means absolute shit.

Put a 1meg ohm resistor (pretty sure its 1meg - if not 100k ohm) on the engine side [female - resistor pins will plug right in the socket]of the KS harness.

If there is a noticable change your;

pinging
ticking
coolant is old
shorting to ground on the KS subharness
KS is cracked
misfiring
exhaust leak
intake leak
cloged PCV valve
incorrect timing
coolant temps are to warm.
electrical grounds are corroded
Motor mounts
Drivetrain noise
something loose in your oil pan yada yada etc....

If there is no change plug the subharness back in, install the resistor at the ECU;

If there is a change then your shorting to ground, plus possibly the above.

Slap the resistor on there and forget about it. Ive removed my EGR, using 70% coolant with the KS resistor running @ 20* with 0 issues.

Usually the KS kills power after 3k

vtec mode seems like a big fat exhaust leak

[UNISA JECS]

Knock sensor will control timing retard from ~700rpm all the way up to ~5100rpm

Another way to tell if you got a knock sensor problem is with a timing gun and car all warmed up, you should see 20*degree timing at idle or whatever you may have yoru base timing at, if you have a knock sensor circuit issue you'll most likely see half of you base timing.

The knock sensor does suck balls but for you guys with no way of illiminating it vis a tunnale ECU hopefully the resitance mod works, because driving with retarded timing not only kills performance but gas milage in a big way.

[Bigsyke]

If im not mistaken, I dont know if the KS controls engine operations durring idling, esp when adjusting per FSM specs [harness is unplugged].

I was @ 20* regardless

[UNISA JECS]

If im not mistaken, I dont know if the KS controls engine operations durring idling, esp when adjusting per FSM specs.

I was @ 20* regardless

It shoudn't but I noticed on my 91 KA and my other friend 92 KA and my other friends 94 Convert timing would not show 20*degree at idle no matter what so it lead me to believe that it was caused by the knock sensor cause both those cars have a code 34 all teh time no matter what haven;t fixed them yet (looking for that shielded wire :)), mine doesn't do that anymore since the problem has been fixed a long time ago. So its not fact its just a suspision I have, I am able to set 20*degree with Nissan Conzult no problem but after that is done the ECU will command ~10degree at idle.

[s13pignose]

Yea my gas mileage isn't good right now. Not going of numbers but the gas hand itself, considering I filled up this morning. Drop quicker than norm. I'm running 93, and have been since I first noticed the code 34.

How exactly do you fix that wire..like the fact the wire has an outer wire for ground just makes matters worse for me lol. Why can't it just be regular ol' wire..something I could probably jump right in and try and fix. I also how does the wire get messed up anyway is what I don't understand when it's strapped down or binded as a harness.

[UNISA JECS]

You know what you could try giving a shot, is some good old RCA cable I think there basically made with UL 1533 cable.

How they fail in every instance I have seen is the spiral shield and conductor meet threw a small break in the PVC insulation as per teh picture below and cause a short to ground either full or intermittent.

http://i167.photobucket.com/albums/u159/zilvia_album/SP32-20090125-104722.gif

[s13pignose]

Yeah I remember u posting that..but how you get the break to begin with is what gets me. SO the length of this cable is pretty much all the way from the sub harness and back into the car at the ecu?

How do you repair the the spiral shield when its wrapped around the inner pvc insulation. I know with a regular wire you could just solder. Thinking if tried here the heat would melt that inner pvc?

[s13pignose]

I breezed through most of the BS;

KS code means absolute shit.

Put a 1meg ohm resistor (pretty sure its 1meg - if not 100k ohm) on the engine side [female - resistor pins will plug right in the socket]of the KS harness.

If there is a noticable change your;

pinging
ticking
coolant is old
shorting to ground on the KS subharness
KS is cracked
misfiring
exhaust leak
intake leak
cloged PCV valve
incorrect timing
coolant temps are to warm.
electrical grounds are corroded
Motor mounts
Drivetrain noise
something loose in your oil pan yada yada etc....

If there is no change plug the subharness back in, install the resistor at the ECU;

If there is a change then your shorting to ground, plus possibly the above.

Slap the resistor on there and forget about it. Ive removed my EGR, using 70% coolant with the KS resistor running @ 20* with 0 issues.

Usually the KS kills power after 3k

vtec mode seems like a big fat exhaust leak


No I'm bringing this thread back alive, but i never noticed that you mentioned exhaust leak till now. Pretty sure I have one, I can hear air coming out the exhaust before it even gets to the exit. So your saying even that can cause a code 34. Also right now I'm running just the mid section of my exhaust..the resonator part. I unbolted the muffler rear section. Any harm in that..been that way for months, even before my car acted weird.

[UNISA JECS]

The ECU doesn't throw a code because it senses knock period, it throws a non-illuminated code when there is a problem with the circuit (i.e. wiring).

[s13pignose]

Thanks..thats was something I was wondering too. I mean I got old motor mounts and exhaust leak...other than the possibility of faulty wiring

[gsxr141]

not to bring up an old thread, but my 89 ka does the same thing between 2-3k. it almost feels like boost coming on at 3k rpm. also when the car is first started, it hesitates in that range too.
does anyone have any suggestions to fix?

[FRpilot]

KA's don't have a "vtec" effect and it sounds like your engine has a problem.

[h22speed]

frpilot your a jackass. there is a need for this thread because a number of people have experienced problems similar to a vtec engine;

no torque
bad gas mileage (obviously not a similarity with hondas, but a problem nontheless)
sudden restore of full power at 5000 rpm's, SIMILAR to the vtec effect


UNISA JECS, did you ever find a stateside supplier for the UL1533 that wasnt out of china? i have repaired 2 places in my ks wire, but am still getting intermittent above symptoms. i also noticed that when the car is first started up and driven it will drive normally then go into this other mode when it reaches a higher operating temperature. maybe another problem?

[kandyflip445]

This stuff looks like it would work. Same basic type of construction.

Parts-Express.com: Pro Co Guitar & Instrument Cable 90% Shield 100 ft. | guitar cable coaxial instrument cable bulk wire bulk cable (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=100-297)

[sileighty83]

Thank you! h22speed for this thread. I agree this was needed! My car as well as many others seem to suffer from the same problem. I was wondering why my car is sluggish at the start then when past 5k rpm boom fast lol

thanks again! more info the better.

frpilot your a jackass. there is a need for this thread because a number of people have experienced problems similar to a vtec engine;

no torque
bad gas mileage (obviously not a similarity with hondas, but a problem nontheless)
sudden restore of full power at 5000 rpm's, SIMILAR to the vtec effect


UNISA JECS, did you ever find a stateside supplier for the UL1533 that wasnt out of china? i have repaired 2 places in my ks wire, but am still getting intermittent above symptoms. i also noticed that when the car is first started up and driven it will drive normally then go into this other mode when it reaches a higher operating temperature. maybe another problem?