Nissan high idle, P0507

[LeakySeals]

Originally Posted by The Critic
The diagnostic info on prodemand says that the fault code is set whenever the idle speed is not within range.

For A/T it is 625-725 rpm. For M/T it is 575-675 rpm.

If you have an AT, then it is probably good enough. For some reason Prodemand did not list the target idle speed, but I would estimare it to be 675rpm on an A/T.

Thanks! That explains why for now the check engine light is not going off after the relearn procedure. It's between 713 and 730 but the high-end must be before it's fully warm or some other parameter. Hopefully after I get that part in I won't have to worry about it anymore. I am starting to wonder about the intake manifold job I did a ways back. The fuel injectors did not go back in so well due to corrosion and brittle plastic caps. I'm wondering if I might be leaking some air around the seals of the injectors.

 

[mclasser]

When I cleaned the electronic TB on my old Infiniti, my idle bumped up to 800-ish. I never got a P0507 but when I tried the idle relearn several times, it never took. The higher RPM really improved the idle quality compared to before so I just left it alone.

These cars are fickle [censored] when it comes to setting the idle but the FSM clearly states that any vacuum leaks will prevent the relearn from sticking.

 

[LeakySeals]

Update: The idle relearn kept the P0507 away long enough to get the new boot installed a few minutes ago. After removal I took a good look at the cracks. They were not through. But wait.. another area I couldn't see till i took it off.. right through... I'm guessing this explains why over time the idle increased until the CEL illuminated? May be too early for Live data, but this was shortly after install, mostly warm. The LTFT is still stuck on 9.4. Maybe that will change now?

 

[Trav]

That is exactly what I suspected. Idle relearn is not for compensation of defective parts, as the engine get miles on it throttle bodies and MAF sensors get dirty, throttle bodies get unplugged and adapted base idle is lost, the ECM compensates gradually for dirty components. Once cleaned the idle will be immediately higher than normal, the relearn will prevent a CEL for the immediate idle increase that may otherwise take the ECM a while to do on its own.
When adapted base idle is lost the ECM uses a default, the relearn will set it close enough for the ECM to adapt quickly.

This pipe and vacuum hoses should be the first thing checked when you get any code that could indicate "false air". Composite plastic ones are far more durable than the rubber ones especially as they get older.

Edit: Damaged injector rings on the manifold side can cause a lean condition. IF this engine uses side feed injectors (yours probably has top feeds) it will cause a rich condition as it will leak fuel not air at the lower ring, this type of injector cannot have an air leak, they leak fuel either internally or externally.
These side feeds are known for breaking pintel caps and blowing the lower ring down causing fuel to flood that cylinder, this can cause engine damage and should be addressed right away.

 

[LeakySeals]

Originally Posted by Trav
That is exactly what I suspected. Idle relearn is not for compensation of defective parts, as the engine get miles on it throttle bodies and MAF sensors get dirty, throttle bodies get unplugged and adapted base idle is lost, the ECM compensates gradually for dirty components. Once cleaned the idle will be immediately higher than normal, the relearn will prevent a CEL for the immediate idle increase that may otherwise take the ECM a while to do on its own.
When adapted base idle is lost the ECM uses a default, the relearn will set it close enough for the ECM to adapt quickly.

This pipe and vacuum hoses should be the first thing checked when you get any code that could indicate "false air". Composite plastic ones are far more durable than the rubber ones especially as they get older.

Edit: Damaged injector rings on the manifold side can cause a lean condition. IF this engine uses side feed injectors (yours probably has top feeds) it will cause a rich condition as it will leak fuel not air at the lower ring, this type of injector cannot have an air leak, they leak fuel either internally or externally.
These side feeds are known for breaking pintel caps and blowing the lower ring down causing fuel to flood that cylinder, this can cause engine damage and should be addressed right away.

So the LD LTFT stats are acceptable ranges?

 

[Trav]

Its high, you probably still have a vacuum leak somewhere.