Possible fueling issues?

DIGItonium

Alright, I'm going to see if you guys can chime in here, which includes pictures of the new gaskets. I took several high resolution pictures, which you can download the ZIP here:
https://drive.google.com/file/d/0B1_...ew?usp=sharing

After removing upper intake manifold the broken bolt was exposed by about 1/4", and I barely used any force removing it. Phew! So why is that the case? There are no stripped threads, so I went ahead and cleaned the screw holes. I even manually hand tightened the bolt on its own and confirm it is not free spinning. I cannot find any cracks, and I even tried shining a flashlight through it.

After taking some pictures, I setup a light leak test by placing the manifold with gasket on a counter top. Then I added a 10 lb weight and shined a flashlight on one side. I even tried pressing down on it, but there's still a bit of light towards the center, but not the runners on each end. This seems indicative of the leak I've been dealing with.


So what's at fault? The new gasket (14032-JK21A) versus the old (14032-JK20A)? Signs of warping towards the center?

__________________

phunk

I cant believe it runs that great without any bolts in the intake manifold at all. Any other car would have the RPMs go way up from no vacuum. That means its idling entirely off VVEL, where I thought it switched to the throttle bodies for idle. Now I am starting to wonder what the hell the throttle bodies are even for on this car.

As for the idle hunting, I was expecting worse than that. I honestly dont know if I would even be chasing after that... looks like 25rpm of movement, thats like nothing.

The light you see under the manifold... hard to say without knowing how flat the table even if. But the bolts will pull it down and conform for a decent amount of warp, if the manifold even is warped.

I am not sure why the bolt broke on you... but otherwise im starting to think things are looking pretty normal in here. I would just put the manifold bolts back in and enjoy the car. Maybe put it on the dyno to make sure all its power is still there and the motor is healthy.

__________________

DIGItonium

Thanks, Charles. It has been an interesting adventure. The engine seems to be running great and throttle tip in feels much better. Looking back I've been dealing with performance issues from possible leaks, fouled up plugs, misfire,etc., since 2013. It is difficult to let go of this car. Your products are on my wishlist when I do pursue a build one day. I wish it would come sooner haha.

Lastly, install it dry or apply silicone grease?

__________________

phunk

I always put it on dry, but I dont see any harm in silicone grease and it might help the gasket seat a little better.

__________________

DIGItonium

I finally got around to ordering a brand new upper intake manifold, gaskets, and bolts. Found out Nissan changed the installation method by using shorter bolts and eliminating the metal spacer in each socket. It turns out over time the old (longer) bolts would stretch. I can confirm with the picture below:


Here are the shorter bolts Nissan is now using for the new intake manifolds:


So even with all new parts installed, no dice. Idle still surges after fully warming up, and I can still confirm the leak from spraying MAF cleaner underneath the intake manifold. My torque wrench is not very accurate, so even at 5 lbs I can barely get it to click. That's how I snapped the old bolt. I carefully hand tighten with the specific pattern, then slowly tighten each bolt. I even took it back out and tried to fully tighten one by one. No dice.

No shops were available to help me out, so hopefully one of my friends is coming by with a better torque wrench. After that I'm giving up. Engine runs great, but this idle surging with the intake manifold is PITA.

[EDIT] Took it to a friend's shop to check the bolts and install the oil cooler fan. He said the surge is so minor I shouldn't worry too much. This is in line what what Charles said as well. So I'll just move on and hopefully get it dyno tuned one day.

__________________

DIGItonium

Just a status of what's going on with my car and see what you guys think. It's probably a tuning issue at the moment.

My car still idle hunts, but only after it warms up. There are times it'll rise to 1.2k RPM for a few seconds, and then back down. The past week it'll hang around 1.2-1.5k RPM indefinitely and throws a high idle code after driving across down. If I quickly shutoff and restart it doesn't idle past 1k anymore afterward. Then I found out both of the 10mm silicone hoses from the PCV (to oil catch cans) had oil residue, so I cleaned and tightened it. I'll try to find thicker hoses that's less susceptible to collapsing under PCV vacuum later. It's doing much better now, but still idle hunts after a warm start.

Other than that it holds 9 PSI boost very well, doesn't lag like it used to, and still no fuel smell. I found a pump across town with 93 octane. It was already running smooth to begin with no hot start issues. It's much more smooth now. Tires are starting to slip more often in 1st

So my next option is the tune, but I rather save up to make the switch to EcuTek and get it dyno tuned. However, I need to switch to EBC first.

[EDIT] Found out the cheap Godspeed catch cans were responsible for at least 95% of all vacuum leaks. I sealed up the cans the best I could with dramatic results. There's still some idle hunting, but nowhere near as bad as before. There were times it could maintain a steady idle. There's still a hissing sound in one of the cans after adding RTV and epoxy to seal up everything I could. These things are terrible and don't hold up well to PCV pressure. Time to cough up more cash for something better.

__________________