You can and will wash your rings running it overly rich due to the cracked manifolds..

I finally started prepping the car last night by dropping the bumper and removing the engine cover. I may try to do a leak test first and am looking for a couple of approaches: smoke test or pressurizing the intake. After doing some reading I'm thinking about plugging the intake tubes before the throttles, removing both intake filters and plugging one of them to test one side first. From there I can feed smoke to the system or pressurize it and listen for leaks.

I was thinking about making a home-made smoke generator using a sealed container in which I can drop in something to generate the smoke. The lid will have 2 lines: one feeding the intake system, and the other to a hand pump.

Is this logical enough?

You could just unbolt the heat shields so you can see the exhaust manifolds and rule that out ...

True. I popped off the oil cap. Fuel smell is stronger. Recent oil change was about 2-3 weeks ago. It definitely runs pig rich. An annoying diesel Ford drive tried to race me the other day. I gave it the 3-4 shift and let off immediately, and there's this crazy loud backfire. I wonder if it shot flames since it scared the driver to the point he started driving civil afterwards. :)

I just started taking a look at the car after dropping the bumper. I straightened the FMIC fins and pulled some gravel out. The BOVs are pristine, and the FMIC pipes are clean as well. I haven't scheduled with anyone to help me to a leak test, but I plan to get some stuff ordered this week.
http://www.the370z.com/members/digit...ngly-clean.jpg
http://www.the370z.com/members/digit...ance-parts.jpg

Black piping looks good.

Thanks. I really wanted black piping leading to the throttles. It's pretty easy to clean, though.

Anyhow, I tried disassembling the BOVs, and it was a pain. I don't have the proper tools so I'm sending them in. TurboSmart charges $25 with shipping to service it, so it's not bad at all. It's way cheaper than the cost of a single K&N air filter.

Brief Update
 

With help from Juan I got around to ordering spark plugs, PCV valves, and gaskets. He recommended that I change the valve cover gaskets as well in the process. The driver side has been leaking for quite some time.

I managed to get the passenger side intake pipe and throttle body out. What a pain! Everything is so clean, and then I finally peeked at the other side of the throttle body. The drive side wasn't too bad, but I had to remove the headlight in the process. The intake plenum definitely needs some cleaning. The inside has this oily residue and smells like raw fuel. :barf:
http://www.the370z.com/attachment.ph...1&d=1432503070

Afterwards I need to try to remember the location of everything before removing the intake plenum and other parts to get to the valve covers. Man I'm such a noob. Although it's nice to get to know my car and digging into the engine, I sorta rather pay someone to do this for me out of sheer laziness so I can get back on the road again. The weather this year is so cool our average temps this month barely hit 70s when we're normally seeing 80s and 90s. :(

Update: Removed Intake Plenum
 

When pulling the PCV hoses I noticed some oil dripping out of the port leading to the passenger side PCV. Attached below is an interesting finding. The intake plenum is pretty nasty. There's fuel smelling oil dripping out of it, and some oil dripping around the gasket (soaked). Three of the runners have plenty of blowby, but the other three barely have any residue. Please note that the passenger throttle has more build up to the point some of the hoses on the same side has some build up as well. The passenger turbo is the one that has been leaking a little bit for the past couple of years on the cold side. At this point I wonder if the PCV is clogged up. I do need to get dual catch cans at some point.
http://www.the370z.com/attachment.ph...1&d=1432535119

The valves look pretty good. Here's an example in one of the oily runners:
http://www.the370z.com/attachment.ph...1&d=1432535119

Oddly enough, I don't see any oil residue in any of the pipes. However, I've not checked the pipes connecting the turbo inlet. The MAFs are super clean, too!

Good to see you resolving the problem. May want to add how many miles since you had this done under boost.

Roughly 45k miles on the kit, and total mileage near 67k. I'm surprised there's no carbon build up in the valves. I am a bit concerned about the slight blue/purple color of the valves in at least 1 cylinder.

Anyhow hopefully my car will run better for the next few years so I can someday get it built haha.

So from looking at the oily residue in the runners leading to the driver side head and seeing that the driver side valve cover has been leaking for quite sometime, could the two be related? After doing some research with VQ35/37 and valve cover leaks, I hypothesize that the main source of the leak is coming from the spark plug seal on cylinder #6. I'm going to find out in the following weeks once I work on the driver side valve cover and spark plugs, which is leaking pretty badly. Perhaps the spark plugs are fairly covered in oil causing some roughness, the couple of times the engine fired on 5 cylinders, and the lack of response.

Anyhow, I washed the intake plenum last night. It smells lemony. I also dipped the MAP sensor in warm soapy water to clean up the oil. It looks hermetically sealed, so I don't think there's much to worry.

To be continued with photos once I get to the cover and spark plugs...

Update: Spark Plugs Removed (2/4/6)
 

To my surprise, there's no oil residue on the spark plugs or holes, so I guess it's just the faulty valve cover gasket. Plugs #2 and #6 seem to look okay for 45k miles, but #4 doesn't look so great. I took a peek at the piston tops, and it has a consistent dry rust look. All of them look the same.
http://www.the370z.com/attachment.ph...1&d=1432705449

About 2 years ago the Z was exposed to extreme summer heat with ambient temps averaging 110-114F for several days since it was still my daily driver. It nearly overheated several times while idling with the A/C, and there was burnt plastic smell as well. I quickly "limped" home on the freeway to keep the temps down and quickly parked the car. I later switched the HFCs to TPs and had the hood vented. The car hasn't overheated since.

Anyway, I'll try to get the driver side valve cover off this week as I wait for parts.

Update: Spark Plugs Removed (1/3/5)
 

After finishing up the driver side, I started work on the passenger side. Here's the condition of the spark plugs below. I notice plug #1 has some sticky oil on the threads, and #3 looks glazed (NGK site points to fouled plugs):
http://www.the370z.com/attachment.ph...1&d=1433224760

Compared to the driver side (solid brown rust color), cylinders #1 and #3 look "splotchy." Here's a comparison photo:
http://www.the370z.com/attachment.ph...1&d=1433224760

I don't really know much from here, but I'm guessing these plugs are fouled up such that not all of the fuel is burned up causing the fuel smell and vapors exiting the exhaust. I'm going to get the passenger cover finished and start reassembling everything. Updates to follow...

Update: She's alive! (6/6/2015)
 

After changing the remaining plugs and reinstalling the passenger valve cover, I started reassembling everything. It wasn't too bad, and my memory wasn't as fuzzy. Started it right up the first time without any issues, and then I performed various procedures from the service manual: throttle closed, accelerator pedal, and idle volume learning. So far it's good. Idle is a bit bouncy, and I'm hoping that's just the ECU trying to calibrate the fuel trims. Other than that, I'll try to check for vacuum leaks.

There's no more raw fuel smell, and there's no visible vapors coming out of the exhaust. It's definitely eager to rev past 4k RPM while idling, where as it was lagging before.

I won't be driving it hard until after I get the oil catch cans and oil cooler fan installed. Plus, I need to get an oil change again since I smell raw fuel in the mixture. Lastly, I need to tell them to avoid overfilling the oil. The dipstick shows oil level around 75-80% mark. I wonder if that's part of the reason for excessive blowby and oil build up in the PCV.

Unfortunately all isn't well. The idle surging won't stop, and ECU threw P0507. I sprayed around the intake pipes and vacuum hose to boost gauge sender, and it didn't make a difference.

[EDIT] I pulled up Cipher. The L/R measurements for MAF and AFR looks good, and it's almost exactly alike. Before the maintenance work there was a significant split between the two. AFR correction is still on the high side around 115% at idle, but it was pretty high before the work was done. So far no fuel smell after taking a drive. It seems to run pretty well, but the idle starts to climb from 700 RPM after idling for a few seconds at the light. I'm going to look over the vacuum lines and replace the zip ties with screw bands.

My car was done nearly 3 months ago and haven't experience any problems except for what you mention about the idling surging. Mine always does it when i put on the a/c its start climbing from around 700 rpms like yours to 1500 and sometimes its stay there,other times it goes down around 1200 rpms and happens every time i stop but if i turn the a/c off the rpms goes back down and the car drive just fine but i need to get that fix cause is makes the engine temperature worst.

Have y'all re flashed recently? If so do the idle relearn and see if that helps

Yes! I will try that and see if it helps thanks jwick

Mine always acts up a bit after a dyno tuning session when my tuner has to re flash it a couple/three times. It usually straightens things out.

I read some people got the code after cleaning the throttles, but since I did more than that I was pretty nervous about the leaks. I cleared the code and did the relearn again. This morning I redid the zip ties to make them as tight as possible, and replaced a hose that didn't fit the barb all the way through. I warmed up the car and didn't notice any idle surge. After a test drive with A/C the idle was tiny bit jumpy, but stooped climbing to 1k and throwing a code. So far so good! A little more work and early oil change to rid the fuel smelling one, and I should be good to go. Still no raw fuel smell or condensation build up on the exhaust tips, so I must be doing something right. :tup:

Cipher Log Observations: 6/8/2015
 

I took a quick drive to my friend's house while treating the car like it is in the break-in period and boost no higher than 2 PSI, half throttle, and keeping the revs below 4k RPM.
https://drive.google.com/open?id=0B1...UjA&authuser=0

For comparision, here's a log taken BEFORE the maintenance work was performed.
https://drive.google.com/open?id=0B1...XzQ&authuser=0

From brief observation, post-maintenance engine idle is a bit higher between 725-800 RPM on average. However, A/F correction seems to be greatly improved (around 105% or so) after about 25 miles total driving. Slight idle bounce exists, but it doesn't seem severe enough to throw a code. There's absolutely no roughness, so engine feels pretty smooth.
http://www.the370z.com/attachment.ph...1&d=1433828992

Before maintenance, the engine idle was intermittently rough (felt like misfire) and shows up as slight bounce. I was already wondering about potential leaks before performing the work.
http://www.the370z.com/attachment.ph...1&d=1433828871

Sunday I checked some vacuum lines. The OEM hoses clamped near the throttle body was easy to twist and pull off, so I added zip ties. The brake booster hose was also a bit loose, so I switched to a screw clamp. I also went ahead and ordered a Z1 brake booster hose. Idle surge was a bit better, but not entirely. At least it's not stuck at 1200 RPM at times or throwing a code.

Last night I grabbed TB cleaner and sprayed around the lines. When I sprayed one side of the intake plenum the engine started stalling. In a span of 3 hours I quickly loosened the pipes, throttles, and removed the intake plenum for inspection. The gasket wasn't even dislodged or deformed. There was a little bit of oil collecting, which was from 25 miles before I installed the catch cans. Nothing seem seeped out of the gasket. At this point I may have messed up torquing the plenum.

It was suggested that the gasket must installed dry with no lubrication despite recalling some sort of jelly (petroleum or silicone) in the grooves before maintenance work (tech who installed my kit must have used it). Anyhow, I washed it and wiped the surfaces clean. Today I spent another 3 hours carefully seating the gasket and intake plenum, hand tightened the bolts in the correct order, and then set the torque wrench at 5 lbs. I wasn't confident and was afraid of over torquing. One of the standoffs in the plenum was loose from the beginning, but it didn't have any major effects. All but #1 bolt seem to hit the torque limit, but I didn't want to push my luck.

After carefully tightening all of the bolts, I plugged the battery in and did all of the relearn process. Engine would still stall if I sprayed the same area. Then I continued carefully tightening the bolts near 8 lbs. Overall I may have spent more time torquing the bolts than I did Saturday.

Only once after startup it would briefly rise to 1200 RPM, but falls back to 600-650 RPM. After awhile it would idle hunt around 700-800 RPM. With the A/C running, idle hovers at 900 RPM. I took it for an easy test drive and freeway driving. Throttle response was better, though it was nice and cool out. It was eager to start boosting. At the light it would still idle hunt. So far no codes. Surging isn't too extreme, but quite annoying. I drove home and tightened up the bolts a bit more and called it a night.

If you think you have a leak any where in the intake. Use starting fluid. Put a nozzle on the can that you can put a plastic tube into. With this, you can pin point the leak when the rpms rise up. Spray small sections at a time. Long as you are pulling vacuum and not boost. ;)

Used this trick when I was rebuilding old carbs that I thought had worn base plates where the throttle blade shaft went through. :tup:

Yea, I did some reading about it. I didn't have any on hand and figured TB cleaner wouldn't hurt, and I was worried about making a mess. But it definitely made the engine bog. I'm not sure if it's related to the leak. I'll try the proper fluid later this week.

I need to do some checking as well. I tried all the realearn stuff and no luck. That idle surge at first i could deal with it but now is driving me nutts.

@VSS370z, can you list the work you done recently?

How's brake pedal pressure? Mine was pretty tight while idling, and it would easily affect engine idle from pressing it down. So far it seems to feel a bit better this time around.

I spent more time carefully torquing each bolt close to 8 lbs than I did Saturday because I was too scared to break things. So far no codes because it's not surging by 200 RPM anywhere near as often as before. The engine isn't freaking out as much as before, and it actually idles a bit lower. I guess that's progress as the bolts are further tightened. It's just #1 that doesn't seem to be hitting the torque limit, which is the same side engine stalls if I spray underneath it. I'm getting brake cleaner spray this afternoon. Hopefully all goes well. If it's still hunting, I'm going to guess it's the MAP sensor at this point. I read a failed MAP sensor could cause the same issues.

Funny thing with the idle hunting is that the engine is actually running smooth and not misfiring. Idle isn't rough.

If you are spraying carb cleaner or throttle body cleaner on the outside of the intake and the engine bogs, you have found a vaccum leak. Address the leak. Look for a sealing issue or a cracked manifold. I would get a new gasket. Silicone is not normally needed on Nissan intakes. You found your issue, now you just have to get it fixed.


Side note: you want to use carb cleaner or throttle body cleaner. Don't use brake cleaner. You want it to burn if it gets into the cylinder.

That's good to know. I didn't want to make a mess and used TB cleaner. The gasket is brand new, and it is not deformed. I thought it was dislodged when I put the intake manifold on the first time, but it looked fine. I took it out and washed it with dish soap and cleaned the intake manifold. I didn't see any visible cracks either.

Last night I made sure to be extra careful and started off hand tightening the bolts in specific order. Then started tightening at 5 ft-lb. I did the test, and the same side bogged the engine, but it seem to idle a bit lower before hunting. Then near 7-8 ft-lb before reaching the "clicking" point, things seem to improve a little bit. While all the bolts are very tight, and I'm carefully turning by 30 deg at a time, #1 hasn't hit the 8 ft-lb limit of the wrench. That's the same side where the possible leak is at. I sprayed the driver side, and it didn't seem to bother. Bolts on the driver side is hitting the limit on the wrench. #7 and #8 was already very tight a bit earlier on. I'm just a little nervous continuing to tighten bolt #1. Before tightening once more and calling it a night, idle was a bit lower and hunting range was probably close to 50 RPM or less. It was less likely affected when I pressed the brakes. So hopefully there's some progress.

I'm going to take a look at it again tonight after replacing the brake booster hose.

Game over. I've completely given up. It was still idle hunting. So I tightened up a bit more and #1 bolt broke off. It's still drivable.

Wish I had professional help to make it right. I'm exhausted.

What were you tightening that broke? The intake manifold bolts? If so, there is no point to torquing then any tighter than stock. Tighter does not make it seal better or seat down any tighter, its just more torque on the bolts, and that is it. There are steel sleeves seated in the manifold that touch down to the LIM and take all the torque load. They have a step machined in them to hold the manifold down. You would have to torque so tight that the steel sleeves deform (not going to happen) before it held the manifold any tighter than standard touch-down.

You just need to make sure the gasket is in good shape. O-ring style gasket, it should be bulging out from the flange and take some decent pressure with your finger to get it to be flush with the plastic flange. If its pre-compressed flat, it needs to be replaced, but I expect that to be very old by then. I just looked at mine with over 60K on it and its a 2009, gasket is still good to go for years to come.

Its most likely a tune issue... either tune or throttle bodies. Assuming you do have an intake manifold leak, while this would increase engine speed and lean out A/F a little at idle (o2 feedback should correct for this though, and show up as heavier o2 compensation that could be logged), I see no reason the engine speed should not be able to remain stable... for an intake leak is accomplishing the same thing as increasing throttle a tiny tiny bit. It shouldnt struggle to accommodate tiny intake leaks... Think of the PCV system, essentially an un-metered intake leak right there - sucking in that crankcase air.

If I was trying to diagnose it, I would get into the UpRev and start by watching MAF voltages and o2 corrections, and seeing what the ignition timing is doing. Goofy ignition timing tuning can cause idle speed to bounce because, all things equal, if you add timing, engine speed goes up... if timing isnt pretty steady at idle, idle wont be steady.

Sorry if some of this was gone over, I didnt read the entire thread.

@phunk, I added links to Cipher logs. Right now I'm looking for someone local to help me out. I've been working alone on this too long and don't have the patience anymore.

The engine would bog if I sprayed the passenger sidea underneath the intake plenum. With the torque wrench I had trouble feeling the clicks. I had it at 5 lbs when the bolt snapped. It's #1, which is same side I sprayed causing the engine to bog.

I would probably pull the manifold back off and examine it in great detail for any cracks or problems with the gasket.

If that bolt snapped at only 5lbs - either that torque wrench is broken or I dont know LOL

Id be curious to see the o2 compensation without engine speed on the scale... I think its making the scale too large to see anything useful on the O2 graphs

Torque wrench is a bit of a crappy one lol. The gasket is brand new. I took it off Monday night to examine it, and I didn't see any issues. As for the manifold, I didn't see anything either. I do recall the tech who installed my kit used silicone grease since it was what I cleaned off. Last night was when I re-installed it.

At this point I don't know what to do anymore. It sounds like an expensive mess. I can do everything else, but the intake manifold has been a nightmare.

Is it pretty useless to log with #1 bolt broken off?

Something is fishy because its just not that sensitive of a situation. I just clean the surface off and wipe off the oring gasket, set it on, and torque it however... I dont focus much on sequence and ive never once torqued it to any spec other than what just felt right. Makes me wonder if your manifold has a crack.

I sorta wondered since the car was having some issues. It's running so much better now other than this problem with the intake manifold. I did what you described, but I was being super careful by hand tightening the bolts and then lightly tighten it at 5 ft-lbs. The ends tightened up first. I guess it's time to get a new one. Ugh... expensive mess. I'd rather leave it in the hands of a pro like yourself at this point.

I don't enjoy the hobby enough to work on the engine. :(

[EDIT] I guess I'll have to pull stuff apart again. A couple of friends will come take a look and will try to get the broken bolt out. Once that is done I'll order a new intake manifold, bolts, and possibly new gaskets. If I can get to the lower bolts on the throttle bodies removal won't be as difficult.

Oh man oh man that sounds horrible!

We have been back and forth in PMs discussing both our problems, sorry you're still having issues.

I messaged Sh0velman a few days ago on Facebook about a way to set up and finally instal my dual Oil catch can system, I can send you the plans if you would like, it's a lot less intrusive then I imagined. Figured you would find it interesting because of your oil blow by.

Keep up updated