[pilsner]

Hey i just replaced my leaky valve cover gasket and now the car has this crazy idelling problem, it won't say at the regular idel, it keeps droping down to like 750 rpms and then goes back up to 1000, back and forth, almost like it's going to die and then goes back up??? all the wire, plugs rotor, timing belt has been recently replaced so i don't know what it could be, help???

 

[Byron]

Check the PCV hoses (small hose from valve cover to throttle body and large from valve cover to turbo intake). Also look for any other vacuum hoses cracked, or left off.

 

[pilsner]

the little hose going from the cover to the throttle body was cracked so i taped it up, would that cause it to idel crazy. BTW what is the purpose of that hose?

 

[senna21]

I know exactly what this is. When you removed your throttle body did you remove it all the way or did you just move it off to the side?

If you removed it all the way then you know you had to remove the electrical connector to and coolant lines to the Idle Control Valve. This valve requires coolant to be circulating through it in order to operate. It opens and closes adjusting the amount of extra air needed during start up and regular operation.

Let me guess what's happening.
1) You start your car up and when it's cold it runs fine and the idle is just over 1,000rpm as it should be.
2)As soon as the car warms up your idle drops down to the 750 point, especially when you've got your foot on the brake and will move up to regular idle when you remove it, or just "whenever".

You've lost coolant from the ICV. When your car is cold check your level. If you open the filler neck and you can't immediately see any top it up. Or just burp the system. Keep topping it up. I'll bet this is the problem.

Also check to make sure the electrical connector is clean and clicked in properly.

Let me know if this fixes it.

 

[highcomp]

have you done any meddling with the mafs sensor because that could be the problem i experienced the same problem as soon as i finished swapping my motor

 

[pilsner]

I know exactly what this is. When you removed your throttle body did you remove it all the way or did you just move it off to the side?

If you removed it all the way then you know you had to remove the electrical connector to and coolant lines to the Idle Control Valve. This valve requires coolant to be circulating through it in order to operate. It opens and closes adjusting the amount of extra air needed during start up and regular operation.

Let me guess what's happening.
1) You start your car up and when it's cold it runs fine and the idle is just over 1,000rpm as it should be.
2)As soon as the car warms up your idle drops down to the 750 point, especially when you've got your foot on the brake and will move up to regular idle when you remove it, or just "whenever".

You've lost coolant from the ICV. When your car is cold check your level. If you open the filler neck and you can't immediately see any top it up. Or just burp the system. Keep topping it up. I'll bet this is the problem.

Also check to make sure the electrical connector is clean and clicked in properly.

Let me know if this fixes it.

That about sums it up, I didn't remove the coolant hoses just some of the sensor connectors and moved the whole unit aside. i did pinch the coolant lines cause i didn't know why there was fluid in them so i pinched it to get out some of the fluid too see what kind it was. i did move it around quite a bit though. like you said, it really only idels funny when it's just sitting there, i'm pretty sure there is fluid in it cause i just changed it about 3 mnths ago.

 

[pilsner]

i'm going to the parts store to get a new valve cover to throttle body hose( little one)
i'll check back to see some replys, I hope this fixes it cause i'm suppost to drive to Sarasota FLA on thursday to visit by cousin, Isn't there a alternator rebuilt shop in Pompano FLA called startech?

 

[pilsner]

So, i took it into toyota and they can't find the problem??? they said they checked all the related sensors and stuff, could it be because i have an ATS throttle intake and it can't measure the air correctly?

 

[senna21]

No. I'm telling you... Burp the coolant system. I'm 99.9% sure this is your problem. Your not getting enough coolant up into the ISC Idle Speed Control.I've been mistakenly calling it the ICV. My mistake. I had this problem just this past week!

Real quick, when your car is warmed up (and idling low) disconnect the ISC. The RPM's should jump up to about 1,000 RPM as it does when the engine is cold. If it does this then it's the ISC... and burp the system to get coolant up in it before you go to replace it. I believe the part is about $200 from Toyota. Concelli Partz Net will have a better price on it though.

http://www.mr2-tech.com/bgb/mechanical/volume1/efi_system.htm

The electronics on it are probably working correctly which is why it won't send an error report to the ECU. But it requires having the coolant in it in order to operate.