wizzards581

well my ecu is throwing knock sensor code. after driving for a while CEL comes on and engine gets weaker. i know its the knock. but i double checked my wiring and it is exactly like my friends on his b18c EG. but mine has knock code. is there a way of checkin to see if the knock sensor is dead? is there supose to be a voltage on the sensor wire? if so how much voltage?

CaptivaBlue

Resurrection!

I have the same problem.

I noticed that on the wiring harness attached to my new engine the ks shield wire was not grounded, nor was it at the ecu end as I have the last foot of harness that attaches to the ecu. I was told to ground the shielding wiring and I did, and I throw a code, could this be the problem?

Jonzo

free bump im getting CEL 23 too

SjCiViCHB

bump. I want to know how to check if the knock sensor is broken...

CaptivaBlue

rebump!

Relic1

if the wires lead to the ECU at the right locations, and there are no shorts, it has to be the sensor. it's either the sensor or the ECU.

it's theoretically possible to test if the sensor is there with a ohm meter to ground.
But I have no idea if the voltage typically put out by an ohm meter will pop the knock sensor.

CaptivaBlue

The sensor is brand new, I just think I grounded it incorrectly, I want to know how someone with one from the factory has theirs grounded.

hott95ej2

use a voltage tester and hit the knock sensor with a screwdriver handle see if it reads anything

CaptivaBlue

I am new to electrical work, could you show a pic of someone doing this?

SkoundrelUSA

bump/subscribe

CaptinMcnut

unplug the knock sensor connector and place a t pin in the knock sensor take a voltage meter and take the red power lead and attach it to the t-pin then take the black lead and attach it to the chassis, put the meter on ac the hit close to the knock sensor you should get some voltage

HondaFanatic708

DO NOT ground the shield. This shield is simply there to protect the KS wire from heat and corrosion. Grounding the shield will most likely throw a code because the electricity traveling to ground will cause so much noise on that little wire that even if it is hooked up correctly it will not function correctly. The KS wire has to be ran from the KS all the way to the ECU when doing any B-series swap in a 92-95 civic. The knock sensor has to be a 20 guage wire, this is critical because too much resistance will still throw a code. The complete signal will not reach the ECU. Just to be OE with the wiring I would suggest getting some old wiring clips from under the hood of a junk car. Most Honda/Acura dealers have this phatty pin replacement kit in the parts department, but good luck getting at this without knowing someone in the parts dept. Sometimes you can get lucky and find that really nice help everyone guy. I personally ran the KS wire to a new pin soldered on to under hood clip # C213. Now that is probably japanese (forgive the pun) if you haven't been working with Honda wiring for a long time. The C213 clip is the 10 terminal clip on the passanger side of the engine bay. If you look closely on the chassis side of this clip you will notice a vacant location (pin8) There will be a brown rubber plug blocking the hole. Disconnect the clip and use a precision (like eyeglass) flat head screwdriver to gently remove the white shroud from the inside of the clip. Once this is removed a gently push of the screw driver in that vacant location should push the plug out. Now that the clip is ready to accept the new pin you have to first run the wire. Use a fish tape (red circle deal with flat metal stirip for running wires) to get through the firewall under the under-hood fuse box. Oh yeah BTW, remove the battery, battery holder and the screws holding the under-hood fuse box in. You don't need to disconnect the fuse box clips though. Run the wire through the firewall. Make sure you have enough length to play with in the car so your not trying to stretch it or anything. Now you can plug the pin into the under-hood clip (chassis side). You will need to then at least zip tie the wire to the loom so you can keep it that stock look. Or you could gently split the loom and tuck the wire inside. Now inside the car take the wire and again zip tie it to the other ECU wires so you don't come up short when re-installing the ECU. You will need another pin to put in the ECU D clip since that location is vacant as well. NOTE: It doesn't have to be a pin out of the ECU clips, there are tons of other interior clips that use the same pins.. Install in D3.. Just to make sure everyone knows the D3 terminal first you must find the D clip. Its the one with 22 wires, or farthest to the right if you are looking at them wire side with locking clips up. Now to locate d3 (pretty easy it's vacant) look at the D clip again from the wire side with the locking clip up and it will be on the top row second from your left. Now that you have the hard part out of the way run the new wire from the KS along the engine harness to the C102 clip (The one that plugs into C213) again use the proper pin. Make sure the pins you use underhood have the little rubber shroud around them as to not allow water in to the clip. For this reason I always just pull pins from old clips. I haven't seen a Honda pin kit that has any of the insulators.. Have fun and good luck.

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CaptivaBlue &raquo;</TD></TR><TR><TD CLASS="quote">The sensor is brand new, I just think I grounded it incorrectly, I want to know how someone with one from the factory has theirs grounded.</TD></TR></TABLE>
the OEM honda knock sensor is screwed into the block, there is it's ground. I've never disconnected my knock sensor but from what I could tell (and can read in the ETM & SM) it's only one wire. what do you plan to ground?

The one wire that has to run to the ECU is to power the sensor(like HondaFanatic708 spelled out), there will be an AC voltage signal that may be able to be read like D94sol said. but it will be .5v max with a good hit on the block next to the sensor. With the engine not running you may have a chance of catching the signal with a DVM, but an o-scope is the best tool for catching the signal.

Also, the shield is all ready grounded through the harness, it's grounded to the thermostat housing in integras and civics. But not for the normally used ground connection, it's there for radiated emissions insulation due to the low voltage signal. (same as the TDC/CKP/CYP/O2/etc sensors)
DO NOT strip away part of the shield to probe the wire, this will defeat the purpose of the shield. Probe at the ECU pin if you want to check it.

One other thing, to be an automotive electrical engineer purist, if the wire you ran for the knock sensor isn't shielded like the OEM wire, it will cause false readings. Maybe not a lot, but they will be there.

HondaFanatic708

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">
One other thing, to be an automotive electrical engineer purist, if the wire you ran for the knock sensor isn't shielded like the OEM wire, it will cause false readings. Maybe not a lot, but they will be there.</TD></TR></TABLE> You could give it a nice wrap with electrical tape since I haven't been able to find any bulk wire with a single wire and this shield. Relic1 you know any vendors hat supply such a wire?

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HondaFanatic708 &raquo;</TD></TR><TR><TD CLASS="quote"> You could give it a nice wrap with electrical tape since I haven't been able to find any bulk wire with a single wire and this shield. Relic1 you know any vendors hat supply such a wire?</TD></TR></TABLE>
I've found that a single leg of 18G speaker wire wrapped in tin foil with black tape around it works well. A little ghetto, but functional.
I know that Digi-key used to carry single lead shielded wire if you want to go that far.