Adjusting Idle on 1991 240sx KA24DE

OK so I think I found the throttle position censor connector (which apparently has to be disconnected to adjust idle), but for the life of me I cannot find the idle adjusting screw… anyone have pics or some good info on where to find this? I have searched all over on the net with no luck at all :frowning:

no one?

can’t you rotate the actual TPS by loosening the two screws holding it on? I am just taking a wild guess btw. There should also be a way to adjust the slack on the throttle cable.

It has been a long time but if i remember the IACV is on the back of the intake. You need a really short philips to get to it.

Thanks for input man! I actually already loosened the throttle cable a bit and it did help, but it can only go so far… dun know about the TPS tho? maybe you are mixing it up wit the distributor? Didn’t know u could rotate the sensor :slight_smile: or maybe I am completely misunderstanding you :E

I will look for that. thanks RS13!

Thanks for input man! I actually already loosened the throttle cable a bit and it did help, but it can only go so far… dun know about the TPS tho? maybe you are mixing it up wit the distributor? Didn’t know u could rotate the sensor :slight_smile: or maybe I am completely misunderstanding you :E

I will look for that. thanks RS13![/quote]

And you can rotate the sensor. There is a write up in the FSM of how to adjust idle and i suggest you follow it or there will be lots of problems.

On the pass. side of the engine near the rear is the AAC valve which lets the ECU control the idle. On that valve body is an idle adjust screw, which isn’t the easiest to get at. Unplug the connector from the AAC and adjust the idle to ~600, known as “hard idle”. Now plug the connector back in. The ECU should now take over what is “soft idle”. You shoul dimmediately notice an engine speed change, if not the AAC may be shot.
The AAC is very prone to faiing as these cars age, and has a tremendous effect on how the car idles, and performs to a large degree.

The TPS (throttle pos. sensor) tells the ECU that the car is in fact in idle condition and adjusts fuel/air accordingly, but it isn’t the item to adjust to correct idle. It does however need to be set properly as it is very improtant. You will need a multimeter, cables with clip ends makes it easiest, and 2 medium size sewing needles, as well as a Phillips screwdriver.
The needles are to gently push into the TPS where the wires enter the housing connector to make connection. Clip the meter plugs onto the needles. Turn the key to ignion on setting. Loosen screw and turn TPS. It needs to read ~.4 to .5 volts when at throttle rest.

Hope this helps