Adjust idle speed

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Hello,

I would like to increase my idle speed on my Q. I think my current idle speed is too low. Can anyone tell me how to do this?

Thanks

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Is there any problem if I just turn the idle speed adjusting crew counter clockwise to increase the idle speed?

Post by **DAEDALUS** » Tue Jan 27, 2004 9:32 am

Which screw are you talking about? There are some you should not touch:

http://www.nissaninfiniticlub....=1005

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

DAEDAULUS,

In section EC of the FSM, they show this one screw that can be used to adjust the idle speed. Turnning that screw clockwise decrease the idle speed and turnning clocewise to increase the idle speed.

What is the best way to increase the idle speed?

Post by **elwesso** » Tue Jan 27, 2004 9:32 am

WHAT EVER YOU DO, DO NOT, DO NOT ADJUST ANY SCREWS ON THE THROTTLE BODY!!! Those are for the FIC (fast idle cam) and could really mess things up....

If you want to adjust the idle speed, you do it by adjusting the IAC (Idle air control)... Its on the back of the plenum, near the firewall.... Youll need a long flat headed screwdriver to reach it... Turn it to the right to increase....

I think, however its time for a cleaning of the TB and IAC, as their probably gunked up since the idle is low.....

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Thanks elwesso,

Should I leave the engine running or off while adjusting the idle speed with this screw?

Post by **elwesso** » Tue Jan 27, 2004 9:32 am

Definitely have the engine running.... Do it about a turn at time (turn and go look at the tach)....

Post by **Q45tech** » Tue Jan 27, 2004 9:32 am

In order for the automatic IAC to function properly [it does alot more than just set idle] like setting the fall off rate of rpm when you suddenly lift throttle at 60 mph to prevent engine stalling.

If the idle is not correct with 2.5-3.5 turns OUT from fully closed you have dirt problems and cleaning is the way to reset the idle properly. Because the IAC is designed to have a 10-15% duty cycle on the bypass solenoid at warm idle in neutral.

We always know when a shade tree has been at work by a misadjusted bypass screw.

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Can anyone explain this?

1. Drove the car for 1/2 hour, 2. Puted it in park 3. Adjusted the idle speed to ~750 rmp 4. Puted the car in Drive and the rmp drop to ~620.

What I really want is to increase the idle speed in Drive to 700 rmp.

Post by **Q451990** » Tue Jan 27, 2004 9:32 am

The idle speed will typically drop when you put the car in D. What was the idle before you adjusted while the transmission was in Drive?

Heath

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Heath, it seens like the RMP in Drive from before and after the adjustment are the same.

Post by **Q451990** » Tue Jan 27, 2004 9:32 am

The ECU will have a target value for the idle, and try to correct it with the AAC valve even after adjusting the base idle. I believe I saw this called the "curb idle" somewhere. I'm not sure that it's adjustable. My thought would be to make sure the throttle body, injectors, air passages, plenum, etc. are clean and then see if your ilde smooths out.

Heath

Post by **TorQue45** » Tue Jan 27, 2004 9:32 am

Thank you Heath for the reply, I am researching my problem and came accross this procedure in section EC of the FSM on the idle speed. I will try it tonight. Hopefully this will do it for me.

1. Put the car in "N" position2. Disconnect throttle position sensor harness connector3. Adjust base idle speed by turning idle speed adjusting screw4. Connect throttle position sensor harness connector5. Erase diagnostic trouble code EC-56

BTW, what are the typical idle speed on Drive when the car is at the operating temperature?

Post by **Q451990** » Tue Jan 27, 2004 9:32 am

Should be specified in your service manual - the older Q was set at 650+/- 50 RPM, but I think the newer ones were higher.

Heath

Post by **maxnix** » Tue Jan 27, 2004 9:32 am

Q451990 wrote:Should be specified in your service manual - the older Q was set at 650+/- 50 RPM, but I think the newer ones were higher.

Heath

Both mine (1995) idle at (judging by inaccurate stock tachometer) about 525-550 rpm, smoothly.

Adjust idle speed

Adjust idle speed

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