Detonation sensor replacement project

[JBender]

I've had my Z32 for about two weeks and it's already on jack stands for a major repair ;D. The car was running poorly, and I pulled Code 34 (detonation sensor circuit) from the ECU. With the detonation sensor located below the intake manifold, I knew I was in for a project, and I haven't done any major engine-related work on the Z31 to provide knowledge and experience. This is the first time I've even removed a plenum, so everything was new from that point on. I have a mechanic friend who is going back to school and is mostly unavailable, so the internet and forums (3ZC, TT.net, here) are my resources. Here is the point I am currently at after about two days that included work shifts.

Click for larger images:

http://www.j-bender.com/z32/730001s.jpg (http://www.j-bender.com/z32/730001.jpg) http://www.j-bender.com/z32/730002s.jpg (http://www.j-bender.com/z32/730002.jpg) http://www.j-bender.com/z32/730006s.jpg (http://www.j-bender.com/z32/730006.jpg) http://www.j-bender.com/z32/730003s.jpg (http://www.j-bender.com/z32/730003.jpg)


I've removed the plenum and related wiring and plumbing. The majority of screws, hoses, and brackets have been labeled so that it isn't a complete PITA when I put things back together. The entire engine bay is very dirty, so I tried using some degreaser on the throttle bodies this afternoon. After soaking, scrubbing, soaking, and more scrubbing, I'm left with TBs that looks like new OEM parts.

http://www.j-bender.com/z32/730004s.jpg (http://www.j-bender.com/z32/730004.jpg)


The plenum is soaking in the sink with some degreaser, so I'll have to see how that comes out tomorrow. I've since drained the radiator and removed the fan shroud in preparation for the work I'll have to do on the front of the engine. From what I've read on other forums, you have to loosen the timing belt tensioner to remove the intake manifold (sometimes referred to as the lower manifold). I've never done any work with belts, accessory or timing, so is there anything I should know in advance to prevent fubar'ing my camshaft / crankshaft alignment? I have a general idea of how the system works, but I have zero experience with most of the engine. It doesn't help that this Z32 engine seems to be much more complicated than my NA Z31 ;). Right now, here is the list of parts from Courtesy Nissan that I plan on replacing with the detonation sensor.

2x PCV Valve - $17.22
2x EGR Valve Gasket - $6.80
1x Z32 PCV Hose Kit - $59.63
1x Non-Turbo Water By-Pass Hoses Kit - $86.39
1x Knock Sensor Kit - $144.60
1x IACV Hose Kit - $61.90
1x Plenum Intake Gasket - $6.65
1x IAAC Gasket - $1.27
6x Lower O-Ring Seal - $14.28
6x Upper O-Ring Seal - $3.48

Total: $402.22

That doesn't include the high-pressure fuel hose below the plenum that I'll be buying locally, or the new spark plugs. I also have to replace either the seal or the hose that connects the radiator to the top of the manifold on the front of the engine, because currently there is coolant leaking from that connection. If there are any additions to that list that I should address while I have everything apart, please let me know. Speaking of spark plugs, they seem fine except for the middle of the #6 cylinder plug. Here is a picture of #6 compared with #4.

http://www.j-bender.com/z32/730005s.jpg (http://www.j-bender.com/z32/730005.jpg)


Is the oil around the plug threads an indicator of some other problem?

I'm taking everything one step at a time, and tomorrow I hope to:

Remove radiator
Remove timing belt cover
Loosen timing belt
Start removing intake manifold


For those who like to skim, here are the questions that I had:

1. I've never done any work with belts, accessory or timing, so is there anything I should know in advance to prevent fubar'ing my camshaft / crankshaft alignment?

2. If there are any additions to that list [parts replacement list above] that I should address while I have everything apart, please let me know.

3. Is the oil around the plug threads an indicator of some other problem?

Thanks for any and all advice and support. I was told that replacing the sensor would have me in over my head (because I have no auto mechanic experience except for fixing the Z31) but I think I'll make it barring any unforeseen catastrophes, and maybe a little forum help as well ;).

[TC]

NICE!!! Carve that into a step by step if you want, and I'll add it as a permanent writeup. Full credit going to you of course.

Gold = best color!

[JBender]

Yeah, I'll look into compiling something once I'm all finished. I'm at the point where I'm down to the timing belt (stuck here (http://www.300zxclub.com/showthread.php?t=60979) for now). I ordered $500 in parts from Courtesy Nissan yesterday, that should arrive around Wednesday next week. The oil on spark plug #6 looks like it might be a valve cover leak in that area. Once I get this timing belt off, I'll be able to get that lower intake manifold and valve covers off.

[JBender]

Parts came in on Monday, but I had to buy the detonation sensor harness locally, because I forgot to put it in my order. I removed the timing belt easily enough (seems the whole cams-jumping-around is when you're moving and removing sprockets, not when you are just taking off the belt). I fought a long battle with the EGR valve and the lower intake manifold last night, and finally won around 11:30. Here is what the detonation sensor looked like:

http://www.j-bender.com/z32/mani4.jpg
Totally trashed


Here are all the parts from Courtesy Nissan: gaskets, hoses, more hoses, misc. sensors, spark plugs, etc.:

http://www.j-bender.com/z32/mani5.jpg


This morning I just started putting things back together. The new knock sensor / harness, lower intake manifold, and fuel injectors with rail are currently back on the engine. I am putting together and printing out several different reference sheets for all the hoses (EGR, PCV, vacuum, coolant, fuel) that form the semi-organized rat's nest on top of the engine, and will take the reassembly of those systems step-by-step.

[JBender]

All the coolant hoses, PCV hoses, and vacuum hoses were a huge PITA. I couldn't find any definitive guides for routing the hoses for an NA, so I ended up using the fiche, the online manual, and various pictures people had taken of their VG30DEs when they were removed for the TT swap. It took several nights of working on the car until 1am, but the car was running Saturday night. No more bad ECU codes! (55 woo) Unfortunately I think I installed the timing belt incorrectly, as a ticking develops on the pass. side, and spreads to the driver's side lifters after a few minutes of running. I'm hopefully going to have a guy come before the end of the week to put the timing belt on properly for me, and then I can focus on working out any other minor engine problems. Another small miracle; no leaks! I can't wait to get the car back on the road; hopefully the guy will come a few days before Friday, which is when I leave with the Z31 for PSU.

[TC]

Lookin GOOD!! Lotsa hoses.......... :)

[JBender]

...5 1/2 months later...

I took it down to the timing belt and back at least three times (I lost count) when I came back from college, and each time it wasn't right and I had to go back down to the timing belt. The last time I was sure I had it together right, until I started it up and it made some terrible noise. Tore it back down today (takes about an hour now, I'm a pro! hehe) and I realized I put the crankshaft pulley backing plate on backwards, subsequently shredding the edge of my new timing belt...oops. Put the 'old' (2 months) belt back on, everything went smoothly as I've had a lot of practice, and...

it's alive!

Idle steady, powerband steady, no leaks, no freaky noises, oh and no code 34.

Lot of people said I was way over my head; I believed it for a while and was starting to get pretty down on this whole process, but there was no greater feeling than pulling the Z out of the garage it has sat in since August '05.

I'm going to replace the front rotors and pads in the next day or two when I get a break from work, and then I'll be making a stop by Ultimate Z in Streamwood, IL to take a look around and see what they can do for me in terms of 'used' parts to replace all the broken small things on the Z.

[TC]

New pics since its running!

Another Goldie saved! Well done!

[JBender]

Just got off the phone with Noyan USA, I have a JDM transmission coming in a few days now. The current tranny has 195k and is very loud (+ 4th gear grind) so the new transmission should make it run much smoother. I was toying with getting a 1-piece driveshaft at the same time, but I'll have to see what this week's paycheck is before I get my hopes up. I come home from college for Spring Break during the first week of March, so the new tranny is getting swapped in, and the Z is coming back to college with me. Depending on how things go, I may / may not take a bunch of pictures and throw together a transmission swap walkthrough for the site.

[JBender]

Well, I swapped in the new transmission, along with a new clutch kit and a resurfaced flywheel, over Spring Break. This all happened in my buddy's shop on a lift, which helped a good deal because we needed to use a torch to get the exhaust off without breaking off any studs. He decided to start early without me on the 2nd day, so I didn't get to be there when the tranny and new clutch went back in, but everything else seemed to go smoothly enough. However, after I drove around a bit, the tranny still seemed noisy. Keep in mind that along with the clutch kit we replaced the pilot bearing and throw-out bearing.

Fast forward to the present, and I've had the Z with me at college for about a month now. The new transmission is nice in that there are no more synchro-grinding issues, but it is still noisy down there, especially with the clutch disengaged (even in neutral). I took it to a local Nissan dealership March 21st, and the mechanic told me he was 90% sure it was my throw-out bearing, and possibly my pilot bearing or input shaft. I told him we replaced those, but I couldn't totally vouch for the correct procedure because I wasn't there when the tranny went back in. Also, the rubber mount in the shifter plate is broken on top, so that could also be contributing to the noise (the previous owner has it ghetto-rigged).

So after that, I figure I have my transmission problems nailed down; replace and/or correctly reinstall the throw-out bearing and pilot bearing. I'm not sure what they could have done wrong because I'm not very familiar with the clutch workings, but I'm going to do what I can in my garage. The plan is to leave Thursday, April 13 and start working on the Z first thing in the morning on the 14th, finishing up by Sunday and driving home then.

At the same time, I've been having some minor engine issues. You can hear a slight misfire in the exhaust at idle, there is some bogging / hesitation during acceleration on occasion through 4k RPMs, and the gas mileage is <20MPG. There is also the smell of gas on occasion in the cabin, but not terribly often. I had them run diagnostics on this at the Nissan dealership, and they told me that I most likely have some sort of leak in the intake system. The same intake system I tore apart to replace the dentonation sensor? Yup. I thought about it for a while...what could I have missed? I went over the parts I had replaced...

...and I never put in any lower intake manifold gaskets. None whatsoever. Ding ding ding, there's my issue. Would explain the misfire (lean condition), poor gas mileage, and occasional bogging. I'm not sure if the fuel smell could be causes by it, but I will take a good look at the injectors while I'm in there to see if any seals weren't set properly.

So in the span of two days or so, here is what I plan on doing:

- Replace the driveshaft with a 1-piece from AMZ (why not?)
- Drop transmission and fix whatever is wrong with the clutch assembly
- Install the Woody short shifter with SPL brass bushings I have on my desk
- Install the new shifter plate
- Take apart the intake manifold / timing belt and put in lower intake manifold gaskets
- Possibly replace the steering rack, at the least replace the u-joint

I'm not sure about the steering rack because both boots are torn and it was leaking heavily before I dumped some Lucas Power Steering Fix in there. I need to replace the u-joint at the very least, because there is some play in it.

On the plus side, because I'm doing this on my own in my garage and I'm a bit more familiar with the process, I can take loads of pics and throw together guides for both the detonation sensor replacement and dropping the transmission :). I've been noticing all the nice work going into the real Goldie cosmetically and it's making my Z jealous, but I have to take care of all these mechanical issues before the money can go into making her pretty.

Even with all her problems, I still get plenty of compliments on campus. Woo :)

[drewtiss]

Great I know something like that.

[drewtiss]

I've had my Z32 for about two weeks and it's already on jack stands for a major repair ;D. The car was running poorly, and I pulled Code 34 (detonation sensor circuit) from the ECU. With the detonation sensor located below the intake manifold, I knew I was in for a project, and I haven't done any major engine-related work on the Z31 to provide knowledge and experience. This is the first time I've even removed a plenum, so everything was new from that point on. I have a mechanic friend who is going back to school and is mostly unavailable, so the internet and forums (3ZC, TT.net, here) are my resources. Here is the point I am currently at after about two days that included work shifts.

Click for larger images:

I've removed the plenum and related wiring and plumbing. The majority of screws, hoses, and brackets have been labeled so that it isn't a complete PITA when I put things back together. The entire engine bay is very dirty, so I tried using some degreaser on the throttle bodies this afternoon. After soaking, scrubbing, soaking, and more scrubbing, I'm left with TBs that looks like new OEM parts.

The plenum is soaking in the sink with some degreaser, so I'll have to see how that comes out tomorrow. I've since drained the radiator and removed the fan shroud in preparation for the work I'll have to do on the front of the engine. From what I've read on other forums, you have to loosen the timing belt tensioner to remove the intake manifold (sometimes referred to as the lower manifold). I've never done any work with belts, accessory or timing, so is there anything I should know in advance to prevent fubar'ing my camshaft / crankshaft alignment? I have a general idea of how the system works, but I have zero experience with most of the engine. It doesn't help that this Z32 engine seems to be much more complicated than my NA Z31 ;). Right now, here is the list of parts from Courtesy Nissan that I plan on replacing with the detonation sensor.

2x PCV Valve - $17.22
2x EGR Valve Gasket - $6.80
1x Z32 PCV Hose Kit - $59.63
1x Non-Turbo Water By-Pass Hoses Kit - $86.39
1x Knock Sensor Kit - $144.60
1x IACV Hose Kit - $61.90
1x Plenum Intake Gasket - $6.65
1x IAAC Gasket - $1.27
6x Lower 4-Seasons A/C O-Ring (http://www.thepartsbin.com/brands/4-seasons/4-seasons_a-fs-c_o-ring.html)- $14.28
6x Upper 4-Seasons A/C O-Ring (http://www.thepartsbin.com/brands/4-seasons/4-seasons_a-fs-c_o-ring.html) - $3.48

Total: $402.22

That doesn't include the high-pressure fuel hose below the plenum that I'll be buying locally, or the new spark plugs. I also have to replace either the seal or the hose that connects the radiator to the top of the manifold on the front of the engine, because currently there is coolant leaking from that connection. If there are any additions to that list that I should address while I have everything apart, please let me know. Speaking of spark plugs, they seem fine except for the middle of the #6 cylinder plug. Here is a picture of #6 compared with #4.

http://www.j-bender.com/z32/730005s.jpg (http://www.j-bender.com/z32/730005.jpg)


Is the oil around the plug threads an indicator of some other problem?

I'm taking everything one step at a time, and tomorrow I hope to:

Remove radiator
Remove timing belt cover
Loosen timing belt
Start removing intake manifold


For those who like to skim, here are the questions that I had:

1. I've never done any work with belts, accessory or timing, so is there anything I should know in advance to prevent fubar'ing my camshaft / crankshaft alignment?

2. If there are any additions to that list [parts replacement list above] that I should address while I have everything apart, please let me know.

3. Is the oil around the plug threads an indicator of some other problem?

Thanks for any and all advice and support. I was told that replacing the sensor would have me in over my head (because I have no auto mechanic experience except for fixing the Z31) but I think I'll make it barring any unforeseen catastrophes, and maybe a little forum help as well ;).

You just have the same problem that my friend used to have. He also got some slight misfiring in the exhaust especially at idle. I wonder how did he managed to fix it.