Low Idle/Stalling Problem...

[perpetual gyro]

Ok, I've been having this problem with my car ever since i bought it a few months ago and i can't figure out what it is. I got a complete 30k tune up overhaul on the car (plugs, oil, filter, fluid flush, injector cleaned, etc) and it still has a low idle...bounces around 500 and sometimes as low as 200 in the cold...even stalls out sometimes. engine light comes on and comes off sometimes, but i can't pinpoint the correlation to the environment or whatever during these intervals. It's pretty much stock (just i/e), and when i put the intake on i made sure the MAF and oxygen sensor stayed on there as well...car is a '95, 95k miles.

Any ideas?

[scruf1986]

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[red240ne]

Does it stall right after you start it, or after it's warmed up?

[perpetual gyro]

when the motor is cold and i'm coasting forward on open clutch, then it stalls..usually also when the the heater/air disengauges...otherwise, it's just a low idle.

[nnkfws333]

Have you tried checking your timing or even adjusting the Idle Screw?

[perpetual gyro]

no i haven't..i would if I knew how though.

[nnkfws333]

ok....to check your timing you need a timing gun. They can be around $30 or more but just check to see if a friend has it. To adjust your idle screw you might have to search for that one. Its a screw on the back of your engine bay, passenger side, near the back of the intake manifold. If you got a fsm it would help alot.

or try http://www.240sx.org might have better info on how to adjust it

[perpetual gyro]

yeah i'm sure one of my friends has one...as for the idle screw, are you talking about the one on the throttle lever?

[nnkfws333]

hum........no I don't think so

http://nicoclub.com/zerothread?id=273&h ... =IAA+valve

try the link there and look under IAA valve....the picture of the screw is viewd from the firewall. If you look go on the passenger side of the car and look behind the intake manifold....8" from the firewall you will see it.

I believe this is what you do.You let your car idle and disconnect your TPS valve connector (above your throttle body closest to you) there are two big connectors the one closest to you is the one. adjust the screw...I forget which way increases the idle. when your done adjusting...turn off the engine. connect TPS sensor back and turn back on.

if you ever get the timing gun......point it at your crank pulley and notice there should be a nail. that should be pointing at the 20 degree mark (mark furthest right). if your left of that mark your running to lean. too much to the right than your running rich. each mark indicates 5 degrees.

try 240sx.org and go to the faq's section it has a write up.

Hope this helps.

[red240ne]

There's always the normal: plugs, wires, timing, and o2 sensor. But, it could be something else. Do a compression test. May be a bad cylinder head gasket.

[red240ne]

Timing gun????ehh??? you mean timing light? whatever. and yes, gyro was right. It's the screw on the other side of the throttle body. Can't remember what it's connected to exactly, but it's right there by the throttle cables/body.

[eastcoastchaos]

nnkfws right on i just read about the exac same problem from a few differant sites, sorry i don't remember them. but i'm pretty sure it is a problem w/ the IAA valve. take it to a nissan shop and they should be able to clean or replace the valve.good luck

[perpetual gyro]

maybe i need a new throttle body gasket...we'll see. i'll just take it to the shop.

[Queamore]

Wait I think you should leave the thorttle alone that can be done on the older cars with no computer but if you do it on the newer cars you mess things up more maybe not right away but eventually. Check all the grounds to the engine clean the all if one is rusty or not tightend down the car will do that. clean them all and tighten them down real good. hope it works.

[240FeVeR]

I see a good amount of bad advice.

Anyway. You should not raise your idle using the screw on the idle air control unit. Why? Because this is just a temporary solution that flows more air at closed throttle, but neglects to solve the real problem.

Your problem will most likely be your throttle position sensor. The black box on your throttle body. On the box itself there is the connection for the idle switch. From the black box runs a wire that connects the throttle position sensor. Your concern is the idle switch connections. Check and make sure they are not fouled up. Check and make sure your idle switch is sending the correct readings using a voltmeter. Get a factory service manula and find out what the correct readings should be as well as the testing and adjusting procedure. If it's not functioning properly, it will not activate the idle air control valve, which is why you have a bad idle. If the idle switch connections are reading properly, check the readings for the throttle position connections. If the throttle position sensor cannot sense it's at closed throttle, it will not activate the idle switch. The throttle is test by checking resistance. A common mistake that people make is that the screw on the black box adjusts the throttle position sensor. It doesn't. It adjusts the idle switch, which is why your idle smoothens out as you adjust it. Your throttle position sensor either works or it doesn't. If it doesn't you can't adjust it, you just have to replace it.