mountainmax

I'm debating whether to replace my KS in a 1993 SE w/178k miles since they usually "wear out" by now, but I've got a couple of questions:

1) I get no KS code in normal driving and will get a 34 when I disconnect the harness, so the basic wiring is OK. I get a 55 all other times. Does a 34 code mean it's a sensor/harness mechanical problem and may or may not be retarding timing, or does it mean the timing has actually been retarded due to a knock? Or could the circuit be considered OK by the ECU, and still be retarding the timing and giving a 55? With no KS code I should assume that it's working right; but I don't know for sure. The reason I'm not too sure of Nissan code logic is that I've got a 1991 300Z that would throw an O2 sensor code (which I almost replaced) but the problem was really a vacuum leak that the O2 sensor couldn't adjust for. I found a pretty good size leak on my Maxima, but it's still a little sluggish in acceleration, so I thought maybe the KS has failed in the "knock" mode, but maybe the ECU doesn't see it because the wiring and KS are OK.

2) Has anyone done a KS relocation or bypass on the VE engine, and if so where did you locate it? I read the KS FAQ's and there was a lot of good info there, but I didn't see any of this addressed.

I may just be fortunate and the KS is still working after all these years...

Thanks
Steve

Matt93SE

iTrader: (44)

if you're not getting a code with the KS plugged in and you are getting a code 34 when you disconnect the harness, then the KS is still good. leave it alone and don't worry about it.

if/when it goes bad, buy a new harness and bolt it onto the front of the head. I found a spot on the front head where it bolted in fine and I'm using it. when I replace the water pump one of these years, I'll put the KS in the proper spot.

mountainmax

Matt , Thanks for the fast reply. I'll save for energy for replacing ball joints or something...

Steve

Dj Paul

iTrader: (1)

ive bypassed the sensor and had great results. if you cant find a 500k ohm resistor. wire 2 1 megaohm resistors parellel and put heat shrink around them and then shove them in there good and tape it up. gas mileage is back up there and power is great again. also the resistors were $1 for 5 of them at radioshack. or if you want to replace the knock sensor ill give you one for $105 shipped

Jeff92se

iTrader: (82)

Um you can buy them brand new for less than $105 shipped. I'm guessing yours is brand new. Internetautomar has them for less I think

Dj Paul

iTrader: (1)

no his are like 125 or 130 or 118 one of those plus shipping maybe

Dj Paul

iTrader: (1)

ya i didnt need mine i ended up bypassing cuz it was too much money to get the intake manifold out once that stupid bolt was stripped. they quoted me the same amount of money i could get new engine with 30k shipped. just to put in a part i already had

internetautomar

iTrader: (30)

I think I've got them up there at $125
Matt- you wouldn't by chance have a picture of where you relocated the sensor too would you?

I know that mt CEL never came on even though my knock sensor was/is non-functional. I did a temp bypass with a resistor and it runs great, now I have to save up the money to have it done

Dj Paul

iTrader: (1)

its not worth having it done, the knock sensor is only needed for situations in which 91+ fuel is not available. if you really think that option is worth it, go for it. i only use premium and see no problem. i would just use the resistor. a good knock sensor reads at 500k ohms. so just pop a resistor in there and use premium fuel which you should be doing anyways on an SE

Jeff92se

iTrader: (82)

I would advise NOT going too long on a ks resistor.

Dj Paul

iTrader: (1)

why? there is no need for it. cars have been going for longer without them. you used to just manually retard the timing to compensate the knock with a timing gun. depending on the mixture. now you give the car the fuel it is recommended to get and it will be fine. stock timing is set in a safety range.

Jeff92se

iTrader: (82)

If the engine sees detonation for any reason, there is no protection. That can happen with stock ecu, good gas and normal conditions. If your engine's ecu uses it for part of it's engine management, then it's there for a reason. But go ahead and continue to use the reisistor.

Dj Paul

iTrader: (1)

thats the exact reason its there for, is to compensate for the unwary or in the instance that less than premium gas is available. detonation occurs due to preignition. this happens when timing is too advanced. or fuel burns at a lower heat in which se's distributerless systems produce a higher heat spark. that is why the ve has more power and needs to use 91+ gas. if you only use 93 and up gas your fine but if only 91 or around that would be a little too close for comfort and in that case i would replace it

Jeff92se

iTrader: (82)

Um the "spark" of the ve is about the same as the VG's spark. Spark is spark. Preignition happens when the a/f lights off at the wrong time. Hence the name. And it can happen at any time. Good luck with your resistor mod.

Dj Paul

iTrader: (1)

..........ok...........do you know how distributorless ignition systems work?

Jeff92se

iTrader: (82)

Do YOU?? ..............

Dj Paul

iTrader: (1)

yup and you do get a higher energy spark due to the coils being directly plugged into each spark plug. why do you think the vg engine only requires 87 or above octane????? cuz it uses a distributor system to fire. i told you i know a lot more about older cars. ive rebuilt an 81 firebird. they dont need knock sensors

Jeff92se

iTrader: (82)

wrong. it has to do with faster recovery

because the compression is lower.

wrong again. look at Integra GSR. note the dist and wires and knock sensor

They didn't know enough about ign systems back then to engineer it into the system. Plus an 81 bird was no where near it's design limits.

Try again.

Jeff92se

iTrader: (82)

Coil on plug ign systems don't deliver a "hotter" spark perse. But a high reving V6 that has to fire many times per sec might put a load on just one coil's ability to "recharge" every time it gets a signal. 6 little coils can charge just once every 6 times vs every time a spark plug needs to fire. But the 2ndary voltage of one VG coil is not going to be that different than the 2ndary voltage of a small VE coil.

Also dist-less sytems don't have to rely on a gears/shafts that can wear out and cause slop. These systems also don't have dist caps and high voltage wires that can be affected my moisture/corrosion and lose energy/cross fire etc..

direct ign systems use either a cam angle or crank angle sensor to precisely measure the cranks position. This position is entered into the ecu and along with many other sensor readings. The ecu then looks up either an open loop or closed ign map and then gives a low voltage ign signal to the appropiate coil. Then the ign signal is ramped up to the correct voltage though the 2ndary and is sent to the spark plug.

I could be wrong. I just typed this in 1 min or so off of the top of my head.

eric93SE

iTrader: (1)

sounds good Jeff

distributor based ignition systems are limited. The distributor-less system is far superior.

5 ltr. beater

WTF!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! You can bypass the KS and still have results?????????
You mean to tell me that i just spent 120$ on a KS and there was another way of doing it?
Is this true? Can anyone confirm this? Someone let me know!!!!!

internetautomar

iTrader: (30)

1. the type of coil does not in and of itself determine the voltage it puts out.
2. the knock sensor is needed because of the higher compression ratio being run on the VE. it is also there because you can't always get 93 octane gas, there are quite a few places in this country where 91 is top. there are also fluctuations within the gas itself.
3. Distributorless is not far superior, it has fewer parts to it, and has it's place as does a well engineered distributor system.

As most of you know, I have the VE with a COP ignition setup and I have my camaro with a plain HEI setup, is one better than the other ignitionwise?
no, they both work within the parameters they were designed for.
Can they both be improved upon?
Absolutlely, all cars are designed as compromises.

internetautomar

iTrader: (30)

you can bypass it, but if you accidentally get a tank of 87 in there, you may end up with piston soup.
not a cheap option IMHO.
my bypass is strictly for testing purposes.
sad thing is now I need to buy a KS and the shop has to put it in

mountainmax

Looks like this started quite a discussion about the dreaded knock sensor. The idea to relocate it somewhere else on the engine block is a good, plausible solution, as Matt describes, and saves from having to pull the intake manifold. The option to bypass it is a little more risky, and you have to consider what kind of driving you do and what kind of gas you have available. Being older and wiser than when I purchased the vehicle, I don't hit the rev or speed limiter like I used to. The bypass means you have ZERO knock protection, but will not have the timing retarded indiscriminately by the ECU. I live at 7,400 ' and run 87 octane gas (considered mid-grade here) without any problems, and I guess my KS is still working. I run premium (91 octane) in my 300ZX TT (when I can afford to drive it) and those have the same KS problems; prone to failure and difficult to replace. The bypass really won't work with those because one instance of pre-ignition in boost will most likely destroy the engine.
I think I'll leave mine alone for now and work on the suspension...
Thanks for the replies!

Steve

DARHAW-MAX

. . . however, the question still stands: where to relocated the new knock sensor? A pic would be wonderful for those who would like to replace the KS w/out all of the intake and manifold mess.

Matt93SE

iTrader: (44)

dude, from what I've read today, you don't know d!ck about cars- new or old. Please stop talking out your @ss on subjects you obviously know NOTHING about.
the knock sensor is there to detect preignition, PERIOD. It has NOTHING to do with the fuel used or the ignition system on the engine..

If your stated case was true, then why the hell do VGs have a knock sensor on them as well? They use a standard distributor for ignition and the ECU still controls timing to some extent.

the knock sensor on the VG isn't the same one that's in the VE/VQ/KA/SR engines, but they're still there, and they're still attached to the block, and the engine still retards timing when they see detonation.

The VE is also still susceptible to knocking and pinging even when running 93 octane and stock timing. been there, done that, rebuilt engines destroyed by it and your stupid resistor "mod"

See this pic? http://mattblehm.com/240SX/IM001601.JPG
that's what happens when you bypass the knock sensor and keep driving. the detonation burned off the piston crowns and completely ruined that engine. that was on the 240 I picked up with a blown engine, but the same thing happens on a VE if you keep driving on it.


Think it's fine? leave that resistor in there. come to Houston or OK where it's >100F in the summer and drive around for a while. sit in stop and go traffic for a couple hours or make a a half dozen passes at the track or spend all day on a road course like I do while the engine is detonating. When you're done, pull the heads off the engine- if they're still on there- and I want to see those piston crowns and quench pads on the head. we'll check 'em for cratering.

Keep talking man.. we really wanna hear your theories on engines now.

Jeff92se

iTrader: (82)

In general, they are superior. Much more precise crank position, less voltage losses though the wires and less problems with coil saturation.

A low reving Chevy V8 can get away with this as the rpm range is fairly low. Spin that engine to 7k+ and you might run into problems. Nothing a MSD upgrade couldn't handle. But a COP ign could handle it no problem

There is a reason why there are Accel/MSD dist upgrades and very few COP upgrades.

I admit once dist systems got ride of that ANCIENT points and vaccum advance/retard it was GREATLY improved. But you still have to deal with the play in the gears etc..

Honda does a good job by mounting the dist right on the end of the cam to reference crank position. divide by 2 or whatever.

Wiking

Superiority is on salesman side, leaking coilpacks replacement 600$. Oldies cap 20$ plus once lifetime REAL wiring (not ! soothoses). There's no real boost compared to coilpacks if wired with real copper wires. [More precise, possibly, but nobody can measure difference]
Reference: http://www.cardomain.com/memberpage/748507/12


Nissan made KS to have globally reliable engine: give it whatever sootwater, it still runs. The lowest octane I can get HERE is superclean 95, the other option is 98, no KS is ever needed HERE, sorry boys. These type V6's have been running with equal hp for 50 years - without KS. Of course dirty hot engine will make ping, and by pressing gas will be destroyed. But anything can be destroyed with stupidity, KS is no warranty against evil world.

Resistor mod is not stupid, its practical from some viewpoints. And bypassing method is the only real way to troubleshoot if KS system works. Running clean engine with 93 or higher is practical and does not endanger the engine no more today, that it did in the 70's.

One may retard the engine to 5BTDC and drive with whatever octane: where is THE BENEFIT OF KS if u do manually what is done electronically? Absolutely nowhere.


Still as stupid system as Knock Sensor is, its practical from Nissan global reliability viewpoint. Anyways, Take care, and listen u horses wellbeing.

Wiking

One life example without KS, result twins:

Mama Dixie and her 87 daughters: engine cranckshaft bearings gone... "KS!? bypass!? I will sue that resistor man!" ...she will scream.

Aunt Svensson with her kennel95: her sisters kids will inherit her V6 year 2030 and continue driWing Wikings decades to come. "KS? Förlåt mig..." they'll ask...

Jeff92se

iTrader: (82)

Um yes there is. Long gear drive dist will NOT read crank angle as well as a direct cam/crank sensor.

If the ecu was designed not to use the ks, of course. But if the programming was designed for a ks, then yes, it's necessary. Go ahead and run w/o one. Have fun sourcing another vg.

Wiking

Mech difference exist [minuscle gearplay], cannot be measured from pwr output.

No secret ECU program: detects ping, retards ign. No ping, no noThing.

internetautomar

iTrader: (30)

I was just refering to DIS in general, COP is the best IMHO, but unfortunately the priciest and I haven't seen an aftermarket setup for it yet.
and for the record that honda distributor design sucks as does the altima design, both are frequent candidates for replacement.

Brad92SE

iTrader: (9)

Would it be a good idea for me to bypass my knock sensor? I think its pulling my timing back....
















j/k btw

internetautomar

iTrader: (30)

Good thing it's cold outside right now, knock bypass isn't too dangerous at the moment

Jeff92se

iTrader: (82)

Yeah they wear out alot. But the theory is sound.

internetautomar

iTrader: (30)

theory is a wonderful thing.
I still like my HEI. 2 wires and it's ready to go

Jeff92se

iTrader: (82)

Hey I like HEI, ESPECIALLY if I end going with my swap. No arguments here

blacks92seAuto

did you bolt the KS in the front head to an existing hole? did you have to drill and thread a hole for the KS to bolt to? got pics?? and does having the KS on the front head prevent it from picking up knocking on the back 3 cylinders?

Jeff92se

iTrader: (82)

Just open the hood and take a look around. There are lots of existing places to bolt the ks to. Technically, I'd bolt it to the block as that's where the the oem on is bolted to. Yes, imho the ks ability to sense knock is dimenished but it's better than the resistor mod.

92SE_Dave

I fully plan to bypass my knock sensor.

Why spend big bucks to have a sensor whos only purpose is to retard your timing ??

I agree that the sensor is not necessary. It is only an added feature for people who cannot adjust their own timing or take the care to use proper fuel and LISTEN for a knock (it is NOT a discrete sound, very noticeable). When you find you are getting knock with premium fuel, retard timing by 1-2 degrees, until knock is gone. Static base timing is far preferable for gas milage and power.

On the flip side, if you are still not getting knock without the KS installed, ADVANCE your timing by 1-2 degrees, until you DO get knock (it takes many knocks to ruin a motor), then reatrd slightly. Engine gets greatest efficiency at highest ignition advance before knock occurs. ECU may not even be taking fullest advantage of engine, since electronic advance is no doubt limited.