Possible fueling issues?

KratikosG37

Black piping looks good.

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KratikosG37 Build Log
http://www.myg37.com/forums/build-th...ml#post3888739

DIGItonium

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.

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DIGItonium

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.


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.

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DIGItonium

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.


The valves look pretty good. Here's an example in one of the oily runners:


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!

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KratikosG37

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

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KratikosG37 Build Log
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DIGItonium

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.

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DIGItonium

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...

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DIGItonium

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.


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.

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DIGItonium

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):


Compared to the driver side (solid brown rust color), cylinders #1 and #3 look "splotchy." Here's a comparison photo:


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...

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DIGItonium

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.

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DIGItonium

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.

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VSS370z

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.

jwick

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

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

VSS370z

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

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.

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