my 240sx aint runin right help!!

[ka24depower]

iI've got a 1990 240sx and the RPMs when the car is runing likes to jump between 400 and 900 ive changed the 02censor and the injecters,plugs,plug wires,cap,rotor button and ive tryed reseting the computer.If anyone knows whats goning on please help!Could it possibly be the mass air flow censor?My car also burns rich exhaust.

Modified by ka24depower at 8:49 PM 5/3/2005
Modified by ka24depower at 8:52 PM 5/3/2005

[streetracer]

Did you try the Throttle Position Sensor It is mounted on the side of the throttle body.(were the air in take hooks to the engine at)

[NateDogg]

Sounds like a corroded connector at the coolant temp sensor, or any other sensor. Also could be the ground to the MAFS. Do a search and you shall find.

[slydin'240]

You can also try cleaning the MAF and throttle body with carb and choke cleaner. Just don't mess with the little spring in the MAF. You can spray it just don't touch it.

[ka24depower]

hey guys thanks for trying to help.ive done all the things you told me but my cars idle is still jumping up and down.ive changed the maf sensor,and i checked the coolant temp sensor and it was fine but i cleaned it any ways,i also changed the throttle position sensor.but hey it cant hurt to have new parts.some one told me it could be the egr valve. do you thank this might be the problem. if you thank so how much would one be.or do you thank i could get one off a parts car and be safe.thanks

[slipnfall]

Warm it up, shut it off, then disconnect the throttle position sensor. Does the problem still exist, or does the idle steady?

[ka24depower]

hey man do i need to let the car cool back off and then hook the censor back up or what.

[NateDogg]

^NO.

To check the EGR, push up on the diaphragm from under the EGR and if the engine dies, it's most likely not your problem. You can also see if it's stuck this way.

[slipnfall]

Yeah, you'll have to hook it back up when you're done. Did disconnecting the TPS smooth out the idle?

[ka24depower]

ok ive checked the egr valve and its stuck so im hopeing thats my problem

[slipnfall]

Good call on the EGR valve...Take it off and soak it down with some carb cleaner, and try to get the plunger to move freely.

[ka24depower]

ok ive bought a egr valve of a junk yard 240sx and do you think ti would be safe to use it. i checked it to and its not stuck.but i have a question i have a header on my car and the pipe that runs off th header goes to the egr could that have f*cked it up.

[ka24depower]

hey man yeah i unhooked the tps and it ran smooth,no gas smoke or anything.but as soon as i hooked it up it started doing it again.i belive thats my problem thanks for helping.

[slipnfall]

The pipe that 'feeds' the EGR probably didn't have anything to do with it going bad. The EGR's just gum up with carbon/etc from the exhaust, it's typical. Anyways, unplugging the TPS just forces the computer to use 'base' maps. Meaning the computer will not control ignition timing or idle. Its possible it may be the idle air control valve.

You shouldn't have any trouble w/the junkyard EGR. If you want to be sure that's the problem, just disconnect the rubber vacuum/exhaust lines going to the EGR(from the BPT, the other disc-shaped device back there).

-Slip

[ka24depower]

hey whats up im still new to imports and wheres the idel air valve