350Z - VQ35DE - Dying engine

[Anthonysflying]

As the title states i have a dying engine. The problem can be recreated like so...1. Drive in any gear to 3000+ revs2. Put the Trans in neutral, release clutch and throttle. (free rolling).The result: Revolutions will drop way past idle and the engine will die. There may be a second or two of the engine/ecu struggling to keep things going. but the cut out is usually pretty quick.

I always warm up the engine before driving/revving. This happens regardless of hard acceleration to mid to high rpms or cruising at mid rpms. I performed the reset and relearn procedures but there has been no change. Cleaned the MAF sensor as well and recently replaced the very dirty air filter as part of general maintenance. Any ideas?

Edit: Notice the throttle body had a lot of buildup around the valve blade. I'm going to clean that sucker tonight.

[aris_unlimited]

Did cleaning the throttle body fix it?

[Anthonysflying]

Oh, yeah forgot about this thread. Cleaning the throttle body actually smoothed out my engine some more, like cleaning the MAF. I've come to the conclusion that my dirty air filter has made quite a mess. I'm very convinced its my EGR or possibly my PCV...EGR makes more sense since it is linked to the intake closer to the air filter/throttle body. The EGR is active during highway(style) driving where I'm driving at a decent speed with consistent RPM. Thats the condition where i can recreate the problem every time. There is either a blockage in the hoses or the valve is stuck/operating inefficiently because of dirt buildup. I'll be back with an update after i check that system.

[Anthonysflying]

I'm bringing this topic back from the dead...because i fixed it!

I was going to go have the dealership use a Consult II to reset the idle air volume etc. because I may have screwed up on the manual procedure. Luckily i didn't waste the cash there. I mentioned before that i had replaced the beat up old Nismo CAI filter with a new K&N cylinder style clamped to the end of the MAF sensor tube. I've seen it done many times before and it was necessary at the time. After some more research and helping out a buddy with his TT 300zx i felt a velocity stack would be much better than the straight pipe into filter setup i had. I ordered one from BPI Engineering, got a K&N RF-1009(6" diameter) and it fixed everything! I guess the airflow was too turbulent before. I slapped it on, didn't even do a reset, and drove 8 hours to Carlisle. Not one problem since.

[W O T]

ur saying restricting the airflow caused your car to run better?

[Anthonysflying]

no, straightening out the airflow fixed the problem. i had a cylinder style filter clamped onto the MAF. it was huge and i felt there would be less resistance because of the large surface area. it was not a smooth transition from filter to pipe.

[jwerty1]

it needed the idle air relearn, which cannot be done without the nissan scan tool, you got lucky, but it will happen again

[Anthonysflying]

it needed the idle air relearn, which cannot be done without the nissan scan tool, you got lucky, but it will happen again

It can be done without the scan tool. look up manual ecu/idle air reset procedure in NICO. I performed the reset before installing the velocity stack, the short bit of straight duct on it provided the linear airflow necessary for the MAF to work. One year later and the problem still hasn't occurred again.