Benjamin T

iTrader: (2)

i searched here, but everyone has low idle/stalling issues, which is the opposite of what i'm having.

the rx engine idle speed is too high... almost 950-1000rpm when in gear at a stop. if i put it in park or neutual, it jumps to roughly 1200rpm. and shifting back into gear will get me a lurch. coming to a stop is not good either as the rpms are again too high and i get another lurch as the transmission tries to downshift from 2nd to 1st.

a mechanic friend tried cleaning out the throttle bodies/IACV with a cleaner, but i dosen't seem to have any effect (it was a little dirty around the motor area, but he said he has seen worse). the ECU is not throwing any CELs...

help?

carguy07

Could still be the IAC sticking open, clean or replace. IMO

Lexmex

Agree about it sticking open. That issue happens to me and I usually have to take off the black cover on the IACV turn it and spray in the hole and that takes care of it. A few times, I have to disconnect the battery.

Benjamin T

iTrader: (2)

what is an IAC? is it the same as an IACV, because i already mentioned that it has been cleaned

Benjamin T

iTrader: (2)

lexmex i'm a bit confused... what is this black cover you are referring to? picture aids appreciated.

Lexmex

See this DIY, you'll see black cover as circled below, and if you follow the DIY that should help you remove it.

https://www.clublexus.com/forums/rx3...-write-up.html (kudos to tcheung87 for this).

Lexmex

Yeah, same thing.

Benjamin T

iTrader: (2)

lexmex: i understand now...



i've made an error in my description. the mechanic only cleaned out the part where the red arrow points to. he did not touch the motor. i will have to ask him again.

thanks!

Benjamin T

iTrader: (2)

lexmex... i'm reading the other posts again and everyone has either low or erratic idle, whereas my problem involves the idle being too high... in fact i seem to be the only one with this problem? what makes me so special???

lexus114

Did you try resetting the ecm?

Benjamin T

iTrader: (2)

ecm? do u mean the engine computer/ECU? if so.... no. how do i do that? with a scan tool or disconnect the battery?

andres-eh2

I wonder if you have a bad or disconnected vacuum line

Lexmex

In my case, I've had both issues.

My experience has been this.

When it is low, it's because there is a lot of buildup that just hasn't been cleaned out.

When it is high, it might be a little dirty, but usually the the little flap piece inside has budged on to a small bit of debris locking it in the open position and thus a higher rpm. Everytime I have had RPM (and I've had that more than the low issue since I got back from Mexico) has been that the flap in the IACV was just slightly overextended.

Benjamin T

iTrader: (2)

i've just come back from my mechanic friend. he saw this post and followed the instructions to clean everything out, but the problem still persists. there is no CEL. he looked up the service manual online and followed some sort of instruction on how to do a voltage test on the motor while it was still installed. he says the motor appears to go to the open position with no problem, but he cannot hear it closing. he tried a voltmeter on it but the readings are all over the place.

he did not find any loose or broken vaccum lines in the engine bay. he used a snap-on scan tool on it and reset the ECU but that didn't do anything either.

i did watch him do something... he jumped some sort of fuse in the engine bay, and disconnected the hose underneath the IACV and the idle dropped from 1200rpm to 500rpm, but then it climbed back up to 700rpm with the hose still off... what does this mean?

he wants to hear opinions from here... does the IACV need to be replaced, or is it something else? if it is the IACV, how many parts are involved? is it just the motor, or are there components in the throttle body itself that require replacement... or the entire throttle body altogether???

code58

Benjamin- Did the mechanic take the IACV OFF to clean it? I know a lot of guys take the easy way and just try and get cleaner up in there to the cylindrical valve, but I personally prefer to take it off and do it right. I just went and looked at one I have and it looks like you could take the black part off and then you can turn the little round fitting on the end of the actual valve and change the RPM. It doesn't seem like it would leak vacuum. You would be doing exactly what the electro magnet does. The valve is a cylinder and doesn't really turn very far at all. You do realize that the black part that houses the electromagnet has an adjustment to it, right? There are slotted holes where the 2 screws that hold it on go. IF it needs replacing, what you get in the new part is the black part AND the part it screws to (the small pot metal part that actually has the cylindrical valve in it) The "motor" is actually an electromagnet that moves either way depending on which way juice is fed to it. The throttle body does not have to be replaced. I have one caution. I have factory CD and the figures seem to be wrong. I have read once before on the forums that Lexus admitted they are wrong. The manual shows a resistance of 17.0-24.5 Ohms cold and 21.5-28.5 Ohms hot. The ohms are read from the center contact in the black part to either side (open or closed) The one I have measured something like 2 Ohms on one side and 59 Ohms on the other side and yet once I cleaned it thouroghly , it worked perfect. If you take the IACV off (by draining some of the coolant and removing the screws on the bottom), you can leave it connected to the plug and test it's operation because then you can see what the valve does perfectly. I assume your mechanic has the manual, if not, let me know and I'll give you the procedure.