Jump to content
Sign in to follow this  
Resbum

Proactive Knock Sensor Replacement?

Recommended Posts

I need some advice from long time VG mechanics.

 

I'm currently doing a bunch of engine work that needed doing. Yesterday I got the new timing belt, water pump, and cam seals in so the front of the engine is down to the block. Also, over the summer I drug in 1.5 miles of fire break out across the eastern Oregon high desert. Because of that my whole engine compartment, and all the hidden areas on top of the engine is also filled with vegetation pieces and other debris .

 

I'm not going to pull the spark plugs until I take off the intake plenum and clean out the holes around the spark plugs. I have all the Nissan OEM intake and plenum gaskets and everything else needed to do an R & R to the top of the engine.

 

So, here's the question. Once I have the plenum off it's literally not much work to pull the lower intake manifold off and inspect/replace the hidden rubber coolant hoses, and knock sensor. I have a new Nissan OEM knock sensor sitting on a shelf. Is it worth proactively replacing the knock sensor while the top of the engine is tore down, or not?

 

Thanks. Resbum.

 

Oh, and is there anything else you VG old timers feel is worth doing while I've got it tore down?

Share this post


Link to post
Share on other sites

May as well change it if you have the parts. I have had a few wd21's and never had the knock sensor fail. If it were me I would give it a good cleaning down there and replace all the rubber like you're planning. Maybe the bypass hose if you can reach it from there.

Share this post


Link to post
Share on other sites

Thanks for the answer.

Share this post


Link to post
Share on other sites

I chipped the casting flash out from around the plug wells. They're supposed to drain, but I guess the crew cleaning the castings at Nissan didn't get that memo. The guy I got the idea from used a die grinder and made his pretty but a big screwdriver and a hammer did the trick for me. I was in the same boat as you as far as pulling the intake before touching the plugs due to the debris (largely mouse crap in my case) around the plugs, so hopefully the redneck port job will make my next plug change easier.

 

I also relocated my knock sensor to the back of the driver's side head so that if I ever did need to fool with it, I could do so more easily. The harness was long enough and the threaded hole was there already. I doubt I'll ever need to screw with it, but it was quick and I didn't want to take the intake off again. (I had it off again almost immediately... to anyone comparing intake gaskets, don't get the Victor Reinz stamped steel crap. Fel-Pro worked for me.)

Share this post


Link to post
Share on other sites

Thanks for the casting info. I was eyeing that very thing as I was cleaning. I didn't mess with it, but now I know. I have a VG33E block (blown head gasket), and the adapters to use all my 30's externals on it. When I build it up for the swap I'll definitely open those castings.

Share this post


Link to post
Share on other sites

May as well change it if you have the parts. I have had a few wd21's and never had the knock sensor fail. If it were me I would give it a good cleaning down there and replace all the rubber like you're planning. Maybe the bypass hose if you can reach it from there.

 

As far as knock sensor goes I noticed on my 1995 XE when fixing some things yesterday on it that it appeared to have the plug unattached to anything just hanging there which was also the case on my other 1995 XE that ended up being the case with it as well. Is the only way to access this to remove the intake or is there another way to locate it? I know with the 1995 XE that was parted out I was unable to even locate where it was on it unless they had relocated it somewhere else which either way it was still not plugged in anyway just as my current one is not either.

Share this post


Link to post
Share on other sites

 

... Is the only way to access this to remove the intake or is there another way to locate it?

 

Yep, unfortunately.

 

There's a fair amount of info from people that relocated it to a more convenient spot.

 

There's also quite a few people that say theirs hasn't worked for years and they've just ignored it if the rig is working.

Share this post


Link to post
Share on other sites

The knock sensor is a non emission related component. It retards timming if it detects excessive knocking. It will effect the super charger and the older q45 models. I would replace it simply because the intake gaskets leak around the coolant port and you can clean the intake valves with ease. Relocating the knock to another location defeats it's purpose. Being located in the center of the engine it can better locate the excessive vibration from either head

Share this post


Link to post
Share on other sites

 

As far as knock sensor goes I noticed on my 1995 XE when fixing some things yesterday on it that it appeared to have the plug unattached to anything just hanging there which was also the case on my other 1995 XE that ended up being the case with it as well. Is the only way to access this to remove the intake or is there another way to locate it? I know with the 1995 XE that was parted out I was unable to even locate where it was on it unless they had relocated it somewhere else which either way it was still not plugged in anyway just as my current one is not either.

 

Yeah, IIRC there was an empty plug back there on mine, too. I have heard of some rigs not having knock sensors at all.

 

Oh, and while the intake's off, have a look at the rubber lines running under it, make sure they're in good shape. If you want to check or clean your idle air system, you'll have an easier time of that with it off too.

  • Like 1

Share this post


Link to post
Share on other sites

 

... I have heard of some rigs not having knock sensors at all.

 

 

It turns out my Pathfinder is one of them. I wasn't going to bring it up to avoid any confusion, but since you did, I will.

 

When I first lifted the lower intake off the engine I was like, "What the #$&*?"

 

A very rusty dirt filled hole is all that was where the KS should be, and I couldn't find the wiring pigtail for it anywhere. Also, there was no KS in the couple other places most people relocate them to, either. I then started Googling for more info. I found two references from people who said their Pathfinders didn't come with one. One of those people specifically said he had "... the 1995 Pathfinder SE, with auto trans", that didn't come with one.

 

At that point, knowing that's exactly what my Pathfinder is, I carefully inspected the wiring loom. I even unwrapped the tape and looked inside the plastic protector sleeve that covers the wires in a couple spots. Originally I had thought a previous owner had cut the KS pigtail off, but I couldn't find one sign of any tampering with the wire loom, and there's not one bit of evidence that the factory loom has ever been messed with before I messed with it.

 

With 40 years of wrench turning under my belt I'm now 99% sure my Pathfinder left the factory without a knock sensor.

 

Resbum

Share this post


Link to post
Share on other sites

That would explain why first 95 XE AT 4x4 didn't appear to have one on it when I had it taken apart. Turns out that the 95 XE AT that I am currently driving does not have one either not even seeing anything showing a place for it where it would be at under the intake or anywhere else one could have been moved to either. So guess out of both my pathfinders I have owned now I got ones that didn't come with one on them. So while I have it torn down going to go ahead & change out some hoses & thing as Startibartfast mentioned to take a look at while the intake was off. At least she can get a good refreshing of some things down there before I get it all put back together.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

Welcome to NPORA Forums

 

Please REGISTER to gain full access to the forum.

Make sure you read the Forum Guidelines and don't forget to post a new intro in the New People Start Here! section, to say hi too everyone.

 

-NPORA

×
×
  • Create New...