High idle speed- Nissan N16 Pulsar/ Almera

Thanks, Hotchevy1965. I have already inspected the throttle body, and it shows NO deposits around the throttle valve. It is returning fully to the factory fixed stop. However if I do go ahead and remove the IAC for inspection, I will need to unbolt the throttle body to access it. Then I can inspect it fully. Thanks, Hotchevy1965. I have already inspected the throttle body, and it shows NO deposits around the throttle valve. It is returning fully to the factory fixed stop. However if I do go ahead and remove the IAC for inspection, I will need to unbolt the throttle body to access it. Then I can inspect it fully.

Hi,
Yes, I have found my problem. I did suspect the idle air valve, and it turned out to be right.
I was a bit worried about tackling it, but eventually decided to carefully try. I had to remove the tube connecting between the air filter and throttle body to gain access to the 2 screws that hold the motor of the valve to the body (it is mounted under the throttle body). I didn't know what to expect when I loosened the screws, but to my joy the motor lifts off the body no problem at all! The electrical plug can be released by pressing the tab just above the motor socket, and pulling out. A test with an ohmmeter on the motor showed a short circuit on one of the 4 motor windings. There is no way into the motor, so replacement is the only option, which means buying the complete valve.
There are 6 contacts in the motor. From the centre contact each side to the in- line ones should show a resistance of abt. 22- 23 ohms. Mine showed 0 ohms on 1 reading. There should also be no connection anywhere between any of the pins on one side and those on the other side.
I searced for a best price for the valve. I thought I found it, but when it arrived it was not the valve it was represented to be, so it went back and I received a refund. I am now waiting for the correct one, which I should receive next week... at a cheaper price again, even! Until I receive it, I cannot tell if the bad stepper motor has wrecked the driver in the ECU, that is a very real possibility! I have already enquired re a reworked ECU if I should need it.
So, the valve IS my problem. Yet to be determined is whether the ECU was damaged.
If you find the motor on yours is not faulty as mine was, you can plug the plug back into it, and switching the ignition ON and OFF, it should extend and retract. If it does, it is probably NOT your problem. There is a fuse and a relay in the circuit, but if functioning, they are probably OK also. Their location I have tried to find, going by the manual, and they APPEAR to be placed somewhere near the blower motor. Like I say, the manual is hard to follow!
DO check for vacuum hose leaks that may be bypassing air into the intake manifold, check the throttle valve is returning fully to the stop, and the switch showing fully closed should be ON. The throttle position sensor should show a smooth resistance change as the threottle is opened, and the wide open throttle switch should close when the throttle is abt 3/4 open. Manually cleaning carbon buildup behind the throttle butterfly may resolve any failure to return to closed. Use rag and carburettor cleaner spray. An old toothbrush can be handy.
Have you found the downloadable factory workshop manual? It has been of great assistance, but is incredibly complicated to follow. It is for the European Almera, but most things are identical. I originally downloaded it when I had an aircon problem,there were some differences there, but I got the general idea and was able to rectify the problem at no cost other than time. It would have been very costly to replace the entire control unit.
The manual describes the many resetting procedures related to idle speed, throttle pos. sensor, throttle closed switch,throttle open switch, etc.
It is the ONLY manual available online (probably an error on someone's part), and workshop manuals cost an arm and a leg!
Please contact again if I can help further. Hi, Yes, I have found my problem. I did suspect the idle air valve, and it turned out to be right. I was a bit worried about tackling it, but eventually decided to carefully try. I had to remove the tube connecting between the air filter and throttle body to gain access to the 2 screws that hold the motor of the valve to the body (it is mounted under the throttle body). I didn't know what to expect when I loosened the screws, but to my joy the motor lifts off the body no problem at all! The electrical plug can be released by pressing the tab just above the motor socket, and pulling out. A test with an ohmmeter on the motor showed a short circuit on one of the 4 motor windings. There is no way into the motor, so replacement is the only option, which means buying the complete valve. There are 6 contacts in the motor. From the centre contact each side to the in- line ones should show a resistance of abt. 22- 23 ohms. Mine showed 0 ohms on 1 reading. There should also be no connection anywhere between any of the pins on one side and those on the other side. I searced for a best price for the valve. I thought I found it, but when it arrived it was not the valve it was represented to be, so it went back and I received a refund. I am now waiting for the correct one, which I should receive next week... at a cheaper price again, even! Until I receive it, I cannot tell if the bad stepper motor has wrecked the driver in the ECU, that is a very real possibility! I have already enquired re a reworked ECU if I should need it. So, the valve IS my problem. Yet to be determined is whether the ECU was damaged. If you find the motor on yours is not faulty as mine was, you can plug the plug back into it, and switching the ignition ON and OFF, it should extend and retract. If it does, it is probably NOT your problem. There is a fuse and a relay in the circuit, but if functioning, they are probably OK also. Their location I have tried to find, going by the manual, and they APPEAR to be placed somewhere near the blower motor. Like I say, the manual is hard to follow! DO check for vacuum hose leaks that may be bypassing air into the intake manifold, check the throttle valve is returning fully to the stop, and the switch showing fully closed should be ON. The throttle position sensor should show a smooth resistance change as the threottle is opened, and the wide open throttle switch should close when the throttle is abt 3/4 open. Manually cleaning carbon buildup behind the throttle butterfly may resolve any failure to return to closed. Use rag and carburettor cleaner spray. An old toothbrush can be handy. Have you found the downloadable factory workshop manual? It has been of great assistance, but is incredibly complicated to follow. It is for the European Almera, but most things are identical. I originally downloaded it when I had an aircon problem,there were some differences there, but I got the general idea and was able to rectify the problem at no cost other than time. It would have been very costly to replace the entire control unit. The manual describes the many resetting procedures related to idle speed, throttle pos. sensor, throttle closed switch,throttle open switch, etc. It is the ONLY manual available online (probably an error on someone's part), and workshop manuals cost an arm and a leg! Please contact again if I can help further.