I need some advice about my idle. swapped in a new motor and everything is perfect but the idle. it will idle between 500 and 1000. it fluctuates a little but is pretty constant at one or the other. cold or warm doesn't seem to make a difference. reset computer, no difference.

 

Did u try to adjust the tb screw for idle?

 

no I didn't adjustment any thing but the plate that holds the cable. the intake came off the old motor and everything was perfect with it then. should I try adjusting that?

 

I'm not sure what your problem is.
My idle is at about 1k when I start my car and then after it warms up and some driving it goes down to like 500.

You can adjust the screw on the throttle body but be careful not to put it higher.
Even taking it up to 700 at idle will throw a cel.

 

my problem is that when i start it cold it will idle at 450-500. when it warms up its still at 450-500. some times it'll idle at 1000 warm or cold. pretty random. just seems like it has a low idle. it will idle kinda rough at low idle.

 

I would try Sea Foaming it (you can watch my video in the How To forum).
This could smooth the idle out.

Also check the spark plugs, may need replaced.

If it's neither of these things then it could be a ecu (not likely) or idle air control motor or sensor (more likely).

But either of these should throw a cel.
So that will come if that's the case.

I don't think adjusting the screw will fix it, but you can try it.
Sounds much more like a Sea Foam/spark plug thing to me.

 

ill start there then. no cel. thanks!

 

Also something you can check is your throttle cable itself. Dunno if your other engine was stock or not but people have issues with the throttle cable housing melting when running an aftermarket header or turbo manifold. This causes the cable to stick at times causing a higher idle randomly. Happened to me, never stuck while driving only randomly at idle. Even if youve never modded it wouldn't hurt to check as its possible you could have unknowingly put a kink in the cable housing during the engine swap.

 

thanks for the tip. i'm not turboed and when we put the motor in, i checked the cables and vacuum lines carefully. i did not unhook the battery or reset the computer when i put the new motor in and started it up. the idle was very high (3k, we pulled the throttle cable kinda tight at the plate) and we adjusted it down from there via the plate. got the idles in the right area now just need to get them stable at the proper areas lol. i checked the spark plugs from the new motor and they looked to be in good shape so we stuck with those. i'll try changing them come payday and adjust the throttle screw a little to see if i can get it where i want it (stable at 600-700?)

 

I believe its about 750 +/-50 rpms iirc

 

Mine runs right at 650rpms when hot.

 

i found that the throttle cable has alot to do with the idle. i wouldnt mess with the idle screw on the tb. while the car is running grab the throttle cable where it runs through the clamps in the valve cover and watch the engine rev up and down. its weird why it does it at least it does on mine anyway.

 

so replaced plugs and adjusted the idle a little at the cable

still will idl3 around 500 when cold. a little over 1000 warm. I can't figure it out. I'm going to reset the computrr tomorrow again. could something be hooked up wrong?

 

are you using a stock cam? I used ecuflash to increase my idle to 1000k after installing semi-solid motormounts to reduce the shaking, lower rpms are just teethrattling.

 

Do you have any mods at all and if so what?

Also how many miles have you driven it since it started this?