Seriously weird iacv problem on the ka24e

[skatermatt180]

On my 90 240sx Im having an issue with the iacv. I got the engine running good after a rebuild, but noticed a buzzing noise in the dash and the e-brake light was stuck on. I researched it here at nico and it was a fuse for eng cont. I replaced it and BAM idle is at about 1700 cold and warm. I disconnected the iacv and the idle went back down to its normal self. I reconnected it and I heard this click and WWOOSSH and the idle was back up. Obviously its kicking on when it doesnt need to. I think its iacv, the valve at the back of the intake plenum on the ka24e next to the idle air controller for the a/c, could be the aac, but you get the point if you have ever worked on or seen a ka24e.

What could it be? I adjust tps in spec too, and air bypass screw is all the way in. One thing Im thinking is could it be that I dont have a idle adjustment screw on my throttle body (lost it)? Would the computer detect that and try to compensate? But even with it disconnected it runs fine...so why the compensation?

I dont know Im stumped, somebody with input would be greatly appreciated!!

[allen90]

my 90 240 does the same thing it idles between 1000 and 2000 if its warm or cold

[skatermatt180]

thanks for the bump!

[tjmhillz]

i had same problem replaced the tps and idled back to normal.. b4 my car would idle at 2k hot or cold.. replaced the tps and idled normal. and if ur e-brake light is on check fluid might be low and if its low might have a leak somewhere. hopefully i helped u out or lead u in right direction.. good luck and let us know if it workd.

[skatermatt180]

yeah, i tested the tps and i think it might be bad. Dont know why it would be, it was ok before the rebuild.....but things happen I guess. The ohms read 8 for some weird reason when they need to be a lot lower. The voltage is correct though. I dont know, its easy to replace so Ill give it a shot.

[skatermatt180]

oh yeah and replacing that fuse fixed the buzzing and the light btw

[rogoman]

If your engine continues to idle real high after it's warmed up, check the air regulator unit. It's located on the passenger side of the engine, below the intake manifold, near the rear. There's a hose connecting to it. Pinch the hose when you are having the high idle condition. If the idle speed drops, there's a problem with the unit. Also check the electrical ground connections on the engine for looseness and oxydation.

[skatermatt180]

Problem with the unit as in what exactly? I unplug it and it drops the idle, I plug it back in and the idle raises, seems like its working good to me, its just the ECU is getting a weird signal to it and im trying to find out where the problem to the ecu is coming from. Im trying the TPS right now.