__jb

iTrader: (3)

I continually get a P0327 Knock Sensor Circuit Low Input diagnostic trouble code in my G35 Coupe. I have turned it off with Cipher many times, but it always comes back. I'm concerned that a bad knock sensor might be causing my engine to run on the alternate timing tables and be costing me power.

I've read many posts that say the knock sensor almost never goes bad, yet I get the P0327 constantly. I figure that there is no reason to continue tuning if I might have a bad Knock Sensor, so I ordered a new one. It will be here in a few days.

My question is on replacing the existing Knock Sensor. I have never removed the fuel injection system from my car. I've gotten this far replacing plenums and stuff, but I've never removed the injector rails and injectors.


I plan to release the fuel pressure using Cipher and then just undo the four fuel rail tabs and lift it out. I suppose it's better to also take the injectors out too?

I'm not too worried about removing the lower intake manifold and replacing the Knock Sensor, but are there any tricks about re-installing the injectors again? Do I need to get new injector o-rings? Is there any method of aligning the injectors?

Thanks for any help.

__jb

iTrader: (3)

Has anyone else ever had a Knock sensor go bad?

h2kSPiG

iTrader: (2)

It was a very common problem on older Nissans, like the VQ30 Maximas. It looks like it might become common as the Z33s age.

Toby-22

iTrader: (25)

I had this exact problem, messed up my timing and slowed my car considerably. THe problem for me was both the knock sensor and wire harness. The swap took 1hr and fixed the problem. Car runs much smoother and faster. If your going to do this, replace both. I swapped just the knock sensor and that didnt fix it. Replace both.

My car ran 14.6 with the code, now im gunning for low 13s

__jb

iTrader: (3)

That's great information, thanks. I didn't realize that the Knock Sensor harness could be replaced.

Is the harness something that snaps in or would I need to splice it into the actual wiring harness? Is there a part number for the Knock Sensor harness?

I'm waiting for my new Knock Sensor to come in at the dealership, so I haven't actually taken the plenum and lower intake manifold off yet. I looked through the service manual, but it didn't show a separate harness.

Toby-22

iTrader: (25)

^ its very easy its just a bunch of snap in wires. Took me and two friends less than an hour to finish. There is one snap in connector (baby blue) and its a PITA to get to but if u move the hoses and all the wires out back you can get all of em from the top. I suggest u get the knock sensor wiring harness along with the knock sensor so u wouldnt have to do this crap twice like i did. Your car will be sooo much smoother/faster. Wiring harness can be ordered at the dealer for $80 after tax. Let me know if u have any questions and give us an update afterwards. Good luck!

SuperBlack350z

iTrader: (59)

you don't pull the injectors out. i'll make a little diagram and send you a pm in a bit when i get home.

Toby-22

iTrader: (25)

^he was one that helped out

__jb

iTrader: (3)

Thanks. I don't see anything about a separate knock sensor harness in the service manual. I wonder if it could be because I have a G, not a Z?

Do you have a part number for the harness you bought? That might help me find the correct harness. I always take pictures when I work on my car. I'll post them after I get the sensor and harness replaced.

__jb

iTrader: (3)

That would be great, thanks!

Toby-22

iTrader: (25)

Dude just go to your nearest infiniti/nissan dealer and ask for a knock sensor wire harness. They will help u out.

__jb

iTrader: (3)

I picked up my knock sensor this afternoon.

Maybe it's just an Infiniti thing, but the parts guy at Lokey Infiniti couldn't find the knock sensor harness part number either. He's going to contact an upper lever Infiniti parts source on Monday and get it ordered.

Thanks for your feedback.

__jb

iTrader: (3)

I just heard back from Infiniti and they say I have to buy an entire EGI Harness. I'm not sure what that is.

They say that the part number is 24011AC820.

And it costs $820.

Could the Infiniti Knock Sensor Harness be that much different than a 350Z Knock Sensor Harness? Needless to say, $820 is a lot more than I was expecting to pay.

Toby-22

iTrader: (25)

BS! im pretty sure its not much different from a Z. U shouldn't pay anymore than $80 for one. KEep searching, call other dealers. Other dealers didn't know what i was talking about either tilll i found the right one.

rcdash

iTrader: (18)

jb,

I looked at the FSM (for my 2004.5 5AT G coupe) and there is a small patch cable as JPE22 describes. Looks like a single wire with a grounded outer sheath. There is a testing procedure in the manual. It is a simple wire - just unplug the harness and check for continuity between the knock sensor and the harness at the other end. Also be sure to make sure that the ground and the signal leads are not shorted together (could be an internal short that is not visible).

Good luck!

In regards to the fuel rails, I have only dealt with the CJM rails, not stock. With the CJM you can just undo the 4 bolts and pull up on each bank of injectors. There is usually more resistance in the upper connection to the rail than in the plenum side, so the injectors pull up with the rail. Just be careful to examine the O rings for damage and make sure they don't fall inside the ports. Again, not sure this is of any help with the stock (though those have clips retaining the injectors onto the rail, so I think it would work similarly).

__jb

iTrader: (3)

I have a new knock sensor, but I'm not going to pay over $800 for a cable that I might not need. I'm going to take it apart tomorrow and see what's going on under there. Thanks for all the info.

I looked through the service manual for my G and it looks like there is a small piece of wire that runs from the knock sensor to the harness. (Exactly as you mentioned.) Unfortunately there isn't a part number for it. I'm going to take it apart tomorrow and check the wire/harness like you suggested. If I don't find a bad connection, loose wire, or something, I'm going to install the new knock sensor and put it back together and hope that fixes it.

Thanks for the heads up, Raj. I appreciate it.

Toby-22

iTrader: (25)

Im going to take a picture of it if u want man, its only $80

Toby-22

iTrader: (25)

For the mean time while i look for my camera call these numbers, these dealerships gave me the part number and price for my knock sensor
1-888-590-7222
1-888-836-8709

__jb

iTrader: (3)

Thanks for the information. Those are both Nissan dealerships. I'm concerned that the G35 harness is different than the 350Z harness.

I took a couple of pictures of my knock sensor and harness. See if it looks like the same sensor and harness you have.

__jb

iTrader: (3)

I took the top of my motor off today to get to the knock sensor and harness. You have to remove a lot of stuff to get at one crummy bolt.



Here's my knock sensor. I'm kinda concerned because it looks like the knock sensor harness is pulled backwards. I would have tried to have the harness make a gradual curve around towards the back of the block. Maybe there isn't enough room for that.




Here's where the cable runs out the back of the block.



Is that what the 350Z harness looks like.