As the title states I installed a new manifold. This one was a polished OEM instead of the nasty looking one. Either way it's still an OEM manifold, it's still got the same holes for all the bolts and it's still got all the hoses going to the right places.

However here's my dilemma

Upon install, we heard a knock coming from the engine, a ticking if you will like a bad lobe on a cam almost. I killed the motor immediately, I had previous experience with this in my old car and I ended up shooting a rod later in the game so this already seems like an expensive repair.

I waited a few minutes, took off the upper plenum and inspected the rubber grommets (guides) for the 6 bolts in the middle, make sure they're all there and that one wasn't accidently "sucked" into the bottom end. Fortunately not. I went ahead tightened everything up again starting with the centers and then moved to the outside bolts. Everything seemed to check out. Started the car, let it run a little longer, knock went away after a minute or so. One battle won! YAY me.


Next step was to take it up and down the road for a little test drive (20-40 mph only) just to ensure nothing seemed/felt odd. Did so and indeed everything felt fine.

Next step was to take it on the main drag, speed limit 55. I got onto the road, accelerated okay, got up to about 52-53 and then heard 2 pops. Not loud like blown head gasket, but just like a backfire in the manifold. I took my foot off the gas, then cruised at 45 and then accelerated to 50 again. Seemed okay afterward. Brought her home and parked it. Terrified to take it out again for fear of some misfire/backfire AGAIN.

My friend drove with me and said that while he was behind me the car didn't seem to have the same rumble it usually does, it seemed lower and less powerful.

The old upper plenum had some oil stains on it but nothing major. The new plenum is spotless inside and out. Is is possible that the new plenum is just a little cleaner thus needs time to break in?

I'm hoping someone in the community has experienced this with the Kinetix manifold and is going to chime in and say "nah relax it's all good" and then I'll feel a little more at ease.

Thanks guys

 

Did you install a new gasket and make sure it wasn't damaged during install?

 

It looks like the previous owner installed a black spacer between the manifold and he used RVT sealer between the two. I didn't line it with a new rvt sealer only because I didn't have any on hand. I hope that I didn't break anything

 

I'm confused. In the beginning of the post you said you installed a polished OEM plenum and at the end of the post you referenced a Kinetix plenum. The most common mistake with this install is getting the rubber seal around the oil filler neck caught between the upper and lower plenums which will cause a vacuum leak. If you messed with the throttle body that can cause issues as well. Did you disconnect the battery during the install?

 

What I meant was this is isn't an aftermarket part. Its OEM so it shouldnt cause problems.

No seal caught. I looked at that carefully thanks. I saw how it was put together the first time.

Never disconnected that battery. Was I supposed to? I had to remove the throttle body to swap it over...is this somehow related to that? Should I do a hard reset? Yank the battery terminal a.d reset the ECU so it relearns everything? These cars are finicky lol. I've never had to pull the battery for engine related work

 

How to reset your ECU and perform the Throttle Pedal Release and Idle Air Volume Learning procedures on an Infiniti G35

Before attempting any of the following procedures, it is advisable that you read through the instructions thoroughly and familiarize yourself with them.

A stop watch or an analog clock with a second’s needle will be useful.

ECU Resetting Procedures

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.
Operations Procedures
1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning
Operation Procedure
1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning
Operation Procedures
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.


Idle Air Volume Learning (Throttle Position Learning)
It is better to count the time accurately with a clock. 1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.

( this is from nicoclub.com)

 

^ I just did this not too long ago after a MD iso-thermal/spacer install. Its kind of a bitch the first few times and timing is EVERYTHING. but if you cant get it to work, then you can also unplug the battery, and pump the brake pedal to discharge the capacitors. essentially "hard resetting" the ECU. I didnt try it but I remember reading that in the instructions MD sent me.

Youre positive that nothing fell down into the engine or the throttle body didnt get funked up during the swap? I would start with doing all the resets and re-learns procedures.

 

Success! After taking the car to the shop and getting an oil change, the car is running great. I suspect that it was just a matter of relearning whatever it is it has to relearn. I'm not sure of the terminology, and quite honestly have never dealt with a car that's persnickety about stuff like this but I'm glad it's all figured out.

Thanks for the instructions on resetting the ECU, I'll end up downloading that for myself.

Either way I'll keep track of what it's doing and see if there's anyway to get some better fuel economy, so far I'm getting 15 city and 19-20 highway.