Knock sensor resistor bypass

[J30inthe sun]

Question: My 97 J30 has thrown the P0325 code about 10 times over the last 2 months. Over the last 2 weeks I have noticed a considerable drop in power at wide open throttle. I bought a generic KS with harness on eBay, did the relocation mount but the car is still sluggish. In order the narrow down the problem I am trying the resistor bypass method in the knock sensor ECU side plug. I inserted the resistor as the picture below shows but the the car is still sluggish. The idle is fine & acceleration under 1/4 throttle is totally normal.

Do I need to reset the ECU to get the engine out of "safe (rich fuel) mode"? If so how do I reset the ECU?

Is this the correct way to bypass the sensor with the 560 ohm resistor? The resistor is bridging both contacts in the plug.

Thank in advance for any help!



These are the resistors I am using:

[J30inthe sun]

I found this thead for the 300ZX "How to diagnose and bypass a defective detonation sensor in a 90+ Nissan 300 ZX Twin turbo."

Here is a picture on how to insert the resistor:




Apparently after much searching in should be a 1 mega ohm resistor which I will be trying tonight. And upon further searching my sluggishness may be attributed to the MAF sensor. I'm going to try cleaning that now too.

.

[Junya]

this is great stuff. my CEL came on yesterday also and it read KS. I didnt know you could do this instead of ripping out the IM. thanks for this. ill def try it.

I checked out a youtube video on some guy mounting another KS on a different part of the IM and removing the CEL. by installing this resistor would it have the same effect?

[J30inthe sun]

this is great stuff. my CEL came on yesterday also and it read KS. I didnt know you could do this instead of ripping out the IM. thanks for this. ill def try it.

I checked out a youtube video on some guy mounting another KS on a different part of the IM and removing the CEL. by installing this resistor would it have the same effect?

Yes this should cure the CEL KS code & restore the correct timing and/or fuel mixture setting, HOWEVER if your engine is dangerously knocking the ECU will NOT retard the timing to PREVENT damage. You have been warning. This should be a temporary fix until you can do the KS relocation or regular KS replacement.

Good luck!

[J30inthe sun]

OK I cleaned the MAF. Aitr filter is clean. I have the 1 mega ohm resistor bridging the knock sensor ECU side plug. I checked the ECU side knock sensor plug & it was 546 on my ohm meter which is correct from everything I read, So I think I can eliminate all of these things.

Car starts & idles fine. Under no load (park) engine revs to redline perfectly & without any lag or hesitation. Driving the car lightly (under 1/4 throttle) everything drives & feels fine. However under load (1/2 throttle to full thottle) the car definately is lacking power and almost hesitating & lagging & almost bogging down, also wide open throttle sound very different than what i sounded like before (normal), hard to describe.

Also, I have gotten the EGR code P0400 a couple of times over the last several months. Would a clogged EGR cause my problems listed, loss of power under load?

Guess I'll change out the fuel filter next.

Any other suggestions?

[Junya]

its strange because you and I are having the same exact symptoms. i have the same code illuminating P0400 and P0325 when i got it checked in autozone even after cleaning the MAF with MAF cleaner and new air filter, new spark plugs, injectors work fine (by disconnecting and RPM watching), 4 new bosch 02 sensors,fuel injector cleaner but still nothing.

Light throttle: Great
1/2 throttle: weak and laggy
WOT: Great

My car idles a little rough so I think ill clean out my idle valve this weekend but it doesnt explain the 1/2 throttle lag. Ill be closely watching this thread as well. Sorry i wish i could help

[J30inthe sun]

Changed the fuel filter today. Still have the same problems. GRRRR. The old fuel filter was at least 6 years old. I blew through it & it was like blowing through a large soft drink straw, wide open, FWIW, I have religiously used Shell premium fuel the entire time over the last 14 years.

My code scanner still pulls code P0325 even though the CEL is not on & I have the 1 mega ohm resistor bridging the ECU side of the knock sensor plug, WTH???

Anybody have any ideas? Why am I still getting the knock sensor code?

Is there a was to reset the ECU on the 1997 J30? I am able to erase the codes with my scanner & it will turn off the CEL when it is lit up.

[Junya]

from what i read its looks that our hesitation issues can be caused by the EGR blockage. Im going to try and clean out the tubes (not the EGR itself) and see if that changes anything.

[J30inthe sun]

I checked the throttle position sensor according to the field service manual guidelines and it's functioning perfectly so that's another thing to cross off the list of probable causes.

I'm going to bring it in to the shop because this is past my time & abilities. I'm going to have them clean my EGR tubes since my J30 has thrown that code a couple of times over the last couple of months.

I'll post an update once it's figured out & fixed.

This is the place I take mine: https://www.zfever.com/v1/

[Fever]

Hey guys! Sorry to butt in. I just bought a j30 (1997). It needs a KS. I saw a YouTube vid on were to relocate the sensor. Has anyone tried this? Does it work? Any help would be much appreciated.

[J30inthe sun]

I bought a knock sensor with harness on eBay that was supposed to fit the J30. The harness doesn't fit my car & I just ohm tested the knock sensor in the relocated position. According to the '97 field service manual the sensor is supposed to measurement 500 - 620 k ohms between terminal 2 on the sensor & ground (multimeter must be able to measure 10 mega ohms). This sensor did not measure correctly.

I'm bringing my car to a shop this week to get fixed.

Good luck

[Fever]

Ok thanks.

[WillJ30]

Hello everyone. Looks like you might have to remove and clean your IACV valve. I cleaned mine with some brake cleaner when my idling was sluggish and it improve greatly.

[J30inthe sun]

Hello everyone. Looks like you might have to remove and clean your IACV valve. I cleaned mine with some brake cleaner when my idling was sluggish and it improve greatly.

My car idles perfectly. The idle air control valve is not the issue. The problem is bogging & sluggishness under load at 1/2 to WOT. The idle air control valve only controls the idle.

I think the problem is either fuel mapping due to a knock sensor malfunction / faulty MAF sensor / possibly faulty TPS.

I decided to order a Nissan OEM knock sensor because the first generic one from eBay did not test within spec based on the field service manual. I'm going to give it another attempt before bringing it to the shop. I might even order a new TPS if the new knock sensor does not fix this problem.

[J30inthe sun]

Installed Nissan OEM knock sensor part #22060-30P00 bought on eBay for $35. Installed knock sensor on back top on intake manifold as others have done on here. No more OBDII code P0325.

[Junya]

did it cure your 1/2 throttle bogging issues?

[J30inthe sun]

did it cure your 1/2 throttle bogging issues?

Almost fully back to normal. My car also threw the EGR valve malfunction code several times over the last couple of months so I wonder if that's a factor and I wonder if my throttle bodies need to be cleaned, I don't recall if they ever have been done. The performance is back to about 90% from feeling like it was down 50% from the malfunctioning knock sensor. There is definitely a bid difference.

I'm going to try cleaning the MAF again & see about getting the throttle bodies & EGR cleaned, probably take it to the shop for the latter 2 things. They can hook up the Consult also to see if anything else is going on. I'm at 172,000 miles. Probably time for me to change the plugs again too, they must have at least 60k on them.

[J30inthe sun]

did it cure your 1/2 throttle bogging issues?

My car got worse to the point of a cylinder misfiring due to a faulty fuel injector. At idle cylinder #1 would not fire causing a major rough idle. The ECU threw the code for misfire in cylinder #1. I replaced all 6 injectors and put 6 new NGK plugs in it and now it purrs like a kitten.

My shop told me this is a common problem because these injectors were never designed to run with ethanol. Apparently the ethanol deteriorates the injector over time to the point that they fail.

Another problem was part of the plastic intake piping that connects to the passenger side throttle body was cracked and crumbling away causing a vacuum leak. Thankfully the shop does a lot of custom modding and fabricated a new piece from stainless steel piping.

I now have full power back and the car runs & idles like new.

[Nimbus]

ACCCKKK, My J30 does just as J30inthe sun describes:

"Driving the car lightly (under 1/4 throttle) everything drives & feels fine. However under load (1/2 throttle to full thottle) the car definately is lacking power and almost hesitating & lagging & almost bogging down..."

But in addition after warm my J30 bogs to 4-600 RPMs when idling. Have changed plugs, fuel filter and cleaned MAF. Any better instructions or videos for cleaning IACV valve? What next to check? Seems like it can be 10 other things.

Also, when you say your J30 is "throwing codes" is that in accompaniment with the dash light coming on?
Thanks for the help!