bongt

Starting/idle Problem Rx300

Recommended Posts

I have a 2003 RX300, problem when starting specially when hot weather. I have seen some post regarding my problem and the majority is cleaning the Idle Control Value and/or throttle body. My question is how to you do the above cleaning, is this where you add chemical with your gas. Please HELP. Thanks.

Hey I think I am having the same problem with my 2000 RX300 :( Let me know if you get any helpful replies... Thanks!

I have a 2000 RX300 also. I don't have a problem starting at all. What happens with me is that when idling at a light or whereever, the RPMs drop by 100RPM or more and makes it feel a little rough. If I shift to neutral or park, the RPMs go back up.

While under warranty, I brought it to the dealer but they didn't find a solution even though they tried a few things. The Dayton Lexus guys have been great, no complaints, but would love to fix this idle thing.

Did you try the suggested fix above and did it fix your problem?

thanks

Share this post


Link to post
Share on other sites

I have a 2003 RX300, problem when starting specially when hot weather. I have seen some post regarding my problem and the majority is cleaning the Idle Control Value and/or throttle body. My question is how to you do the above cleaning, is this where you add chemical with your gas. Please HELP. Thanks.

Hey I think I am having the same problem with my 2000 RX300 :( Let me know if you get any helpful replies... Thanks!

I have a 2000 RX300 also. I don't have a problem starting at all. What happens with me is that when idling at a light or whereever, the RPMs drop by 100RPM or more and makes it feel a little rough. If I shift to neutral or park, the RPMs go back up.

While under warranty, I brought it to the dealer but they didn't find a solution even though they tried a few things. The Dayton Lexus guys have been great, no complaints, but would love to fix this idle thing.

Did you try the suggested fix above and did it fix your problem?

thanks

Cleaning the IAC valve could very well fix that problem.

Share this post


Link to post
Share on other sites

I figured it out. Removed the lower portion of the #2 throttle body to perform the cleaning.

Share this post


Link to post
Share on other sites

Ok, all I have read so far is that the idling low and rough. I have a 2001 RX300. The idling has been high and rough. It seems the car never warms up. The gpm has been poor. Could this be the same problen with a dirty IACV?

jw

Share this post


Link to post
Share on other sites
Ok, all I have read so far is that the idling low and rough. I have a 2001 RX300. The idling has been high and rough. It seems the car never warms up. The gpm has been poor. Could this be the same problen with a dirty IACV?

jw

I doubt it would have much of an effect on your gas mileage. Does it warm up on the gauge?

Share this post


Link to post
Share on other sites
Ok, all I have read so far is that the idling low and rough. I have a 2001 RX300. The idling has been high and rough. It seems the car never warms up. The gpm has been poor. Could this be the same problen with a dirty IACV?

jw

I doubt it would have much of an effect on your gas mileage. Does it warm up on the gauge?

Yes, the gauge warms up fine. It's just RPM is high, around 900, and I can feel the vibration. The dealership said it is whin the spec. But it wasn't like this before.

jw

Share this post


Link to post
Share on other sites
My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

I HAVE 2000 ES300 AND THIS ALSO WORKED FOR MY COLD STARTING PROBLEM ALSO(THANKS FOR THE PICTURE, I WOULD HAVE NEVER FOUND IT WITHOUT IT!!!), THANKS!!!!

Share this post


Link to post
Share on other sites
My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

THANKS SO MUCH FOR THE PICTURE,IT REALLY HELPED OUT!!!!!

Share this post


Link to post
Share on other sites
I have a 2003 RX300, problem when starting specially when hot weather. I have seen some post regarding my problem and the majority is cleaning the Idle Control Value and/or throttle body. My question is how to you do the above cleaning, is this where you add chemical with your gas. Please HELP. Thanks.

My 99 RX300 just started having a starting problem. I thought it would be the"starter" but after seeing this post I am wondering if this could be it? My question is: What would be my signal that this is the problem. My car just clicks when I try to start. It does not do it allthe time and after reading this, it actually might just be when it is warm outside. If it was this problem would I hear the engine trying harder to start or would it just be this clicking noise? Thanks!

I think youre problem is your battery connector. check it if there's acid build up , clean it real good with wire brush....

Share this post


Link to post
Share on other sites

There hasn't been a post on this for a while so I thought I would add my story and solution in hopes someone can learn from my experience.

I had the same problem with the idle. Car would not start unless I gave it gas and would die when I let off the accelerator. This is classic Idle control valve behavior. So I looked at AllData and the procedure is to remove the throttle body...I didn't want to go through all that so I looked for another way. Bottom line is that you really do need to remove the Throttle Body to do it right. The IACV is NOT just the black part pictured above...that is just the step motor. The valve is the assembly underneath and has 4 VERY tight screws. I had a hard time removeing them, even with the TB off the car.

Removal of the TB is not for the not so mechanicaly inclined...there are difficult nuts and bolts to reach, hoses to remove (including coolant hoses) and the bolt on the back side (12mm) attaches a bracket and is very hard to reach. The coolant hoses need to be plugged while you have the TB out of the car. Make sure you take a very good look at how the hoses are attached...it is possible to attach a coolant hose to an air port if you are not careful.

Once the TB is off, flip it over on a bench and remove the 4 screws that attach it to the TB. Be careful, there is a rubber/silicone gasket that is somewhat difficult to get back into the recesses when you reassemble. In the valve housing, you will see the actual valve. It rotates to open and close, metering the hole size, allowing air to bypass the butter-fly valves in the TB. Tha is how it controls the idle. Spray with carb cleaner until it is clean and the valve rotates freely. There is some freeplay between the valve shaft and the magnetized head. I was concerned that this was an indication of failure, but when reassembled, it worked fine.

Give the opening in the TB a good cleaning. You may as well clean out all the ports where vacume hoses attach. Re assemble the TB.

When placing the TB back in the car, slip the TB over the intalke manifold studs (you should use a new gasket but i couldn't get one over the Memorial Day weekend) and just start the nuts on the studs. Then try to start the bracket bolt (back side of TB). This was a little difficult...you have to do it by feel and it is very tight for your 12mm wrench. Once started, snug tighten. Then back to the intake manifold studs, snug fit first then tighten them to 14 ft-lbs or 200 kg-cm. I would attach the coolant hoses next, starting with the one on the bottom rear. After that, everthing is reverse order.

One last gotcha...it is possible to incorrectly reinstall the black motor back to the valve housing. Make sure the electrical connector is at the bottom of the assembly.

It is a pain to install everything in order to test the car...If you do not re-attach the Mass Air Flow sensor on the filter housing, the car will start and idle...but you will get a check engine light and it will sputter on reving the engine.

This is kind of long, but I spent 4 1/2 hrs today fixing this and wish I had known what I know now...I would still do the job, but it would have been better knowing what I was getting into. :D

Share this post


Link to post
Share on other sites
There hasn't been a post on this for a while so I thought I would add my story and solution in hopes someone can learn from my experience.

I had the same problem with the idle. Car would not start unless I gave it gas and would die when i let off the accelerator. This is classic Idle control valve behavior. So I looked at AllData and the procedure is to remove the throttle body...I didn't want to go through all that so I looked for another way. Bottom line is that you really do need to remove the Throttle Body to do it right. The IACV is NOT just the black part pictured above...that is just the step motor. The valve is the assembly underneath and has 4 VERY tight screws. I had a hard time removeing them, even with the TB off the car.

Removal of the TB is not for the not so mechanicaly inclined...there are difficult nuts and bolts to reach, hoses to remove (including coolant hoses) and the bolt on the back side (12mm) attaches a bracket and is very hard to reach. The coolant hoses need to be plugged while you have the TB out of the car. Make sure you take a very good look at how the hoses are attached...it is possible to attach a coolant hose to an air port if you are not careful.

Once the TB is off, flip it over on a bench and remove the 4 screws that attach it to the TB. Be careful, there is a rubber/silicone gasket that is somewhat difficult to get back into the recesses when you reassemble. In the valve housing, you will see the actual valve. It rotates to open and close, metering the hole size, allowing air to bypass the butter-fly valves in the TB. Tha is how it controls the idle. Spray with carb cleaner until it is clean and the valve rotates freely. There is some freeplay between the valve shaft and the magnetized head. I was concerned that this was an indication of failure, but when reassembled, it worked fine.

Give the opening in the TB a good cleaning. You may as well clean out all the ports where vacume hoses attach. Re assemble the TB.

When placing the TB back in the car, slip the TB over the intalke manifold studs (you should use a new gasket but i couldn't get one over the Memorial Day weekend) and just start the nuts on the studs. Then try to start the bracket bolt (back side of TB). This was a little difficult...you have to do it by feel and it is very tight for your 12mm wrench. Once started, snug tighten. Then back to the intake manifold studs, snug fit first then tighten them to 14 ft-lbs or 200 kg-cm. I would attach the coolant hoses next, starting with the one on the bottom rear. After that, everthing is reverse order.

One last gotcha...it is possible to incorrectly reinstall the black motor back to the valve housing. Make sure the electrical connector is at the bottom of the assembly.

It is a pain to install everything in order to test the car...If you do not re-attach the Mass Air Flow sensor on the filter housing, the car will start and idle...but you will get a check engine light and it will sputter on reving the engine.

This is kind of long, but I spent 4 1/2 hrs today fixing this and wish I had known what I know now...I would still do the job, but it would have been better knowing what I was getting into. :D

Share this post


Link to post
Share on other sites
There hasn't been a post on this for a while so I thought I would add my story and solution in hopes someone can learn from my experience.

I had the same problem with the idle. Car would not start unless I gave it gas and would die when i let off the accelerator. This is classic Idle control valve behavior. So I looked at AllData and the procedure is to remove the throttle body...I didn't want to go through all that so I looked for another way. Bottom line is that you really do need to remove the Throttle Body to do it right. The IACV is NOT just the black part pictured above...that is just the step motor. The valve is the assembly underneath and has 4 VERY tight screws. I had a hard time removeing them, even with the TB off the car.

Removal of the TB is not for the not so mechanicaly inclined...there are difficult nuts and bolts to reach, hoses to remove (including coolant hoses) and the bolt on the back side (12mm) attaches a bracket and is very hard to reach. The coolant hoses need to be plugged while you have the TB out of the car. Make sure you take a very good look at how the hoses are attached...it is possible to attach a coolant hose to an air port if you are not careful.

Once the TB is off, flip it over on a bench and remove the 4 screws that attach it to the TB. Be careful, there is a rubber/silicone gasket that is somewhat difficult to get back into the recesses when you reassemble. In the valve housing, you will see the actual valve. It rotates to open and close, metering the hole size, allowing air to bypass the butter-fly valves in the TB. Tha is how it controls the idle. Spray with carb cleaner until it is clean and the valve rotates freely. There is some freeplay between the valve shaft and the magnetized head. I was concerned that this was an indication of failure, but when reassembled, it worked fine.

Give the opening in the TB a good cleaning. You may as well clean out all the ports where vacume hoses attach. Re assemble the TB.

When placing the TB back in the car, slip the TB over the intalke manifold studs (you should use a new gasket but i couldn't get one over the Memorial Day weekend) and just start the nuts on the studs. Then try to start the bracket bolt (back side of TB). This was a little difficult...you have to do it by feel and it is very tight for your 12mm wrench. Once started, snug tighten. Then back to the intake manifold studs, snug fit first then tighten them to 14 ft-lbs or 200 kg-cm. I would attach the coolant hoses next, starting with the one on the bottom rear. After that, everthing is reverse order.

One last gotcha...it is possible to incorrectly reinstall the black motor back to the valve housing. Make sure the electrical connector is at the bottom of the assembly.

It is a pain to install everything in order to test the car...If you do not re-attach the Mass Air Flow sensor on the filter housing, the car will start and idle...but you will get a check engine light and it will sputter on reving the engine.

This is kind of long, but I spent 4 1/2 hrs today fixing this and wish I had known what I know now...I would still do the job, but it would have been better knowing what I was getting into. :D

Share this post


Link to post
Share on other sites

Slider9, give it another try. Just delete all the text and put in your comments.

Share this post


Link to post
Share on other sites
I'm having same problem too. On cold start, idle speed is very low or won't run at all without pushing on the accelerator. After warm-up it is ok for the day. Will clean valve and see what happens.

JetPilot

Clean the Valva and it should solve the problem.

Take off the air filter box lid.

Remove the air filter box along with the filter.

Remove air hose which is attached to intake / throttle body.

Remove th valve....note..the phillips head screws are easy to strip so make sure you have the proper size phillips head screw driver.

Clean enitre valve thoroughly with throttle body / carb cleaner.

Re-assemble, and this should help eliminate the problem. If not, check for fouled plugs, stretched line from accelerator to throttle control, or fouled coils.

what he said also there is a real thin round black gasket... don't loose it!!

Share this post


Link to post
Share on other sites

My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

Be careful not to strip the two screws when removing them. It is challenging to break the factory torque to loosen those screws so find a very tight fitting screwdriver that will do the job. I am in the middle of cleaning my IACV myself..

Thanks so much. I did as you said and it runs great now.

Share this post


Link to post
Share on other sites
I'm having same problem too. On cold start, idle speed is very low or won't run at all without pushing on the accelerator. After warm-up it is ok for the day. Will clean valve and see what happens.

JetPilot

Clean the Valva and it should solve the problem.

Take off the air filter box lid.

Remove the air filter box along with the filter.

Remove air hose which is attached to intake / throttle body.

Remove th valve....note..the phillips head screws are easy to strip so make sure you have the proper size phillips head screw driver.

Clean enitre valve thoroughly with throttle body / carb cleaner.

Re-assemble, and this should help eliminate the problem. If not, check for fouled plugs, stretched line from accelerator to throttle control, or fouled coils.

Thanks, I did as instructed and now works better than it has in 50k miles. The vehicle now has 167k on it.

Share this post


Link to post
Share on other sites

I just performed the AICV cleaning on my 2001 RX300 based upon this writeup. EXCELLENT!!

I told my wife I just saved her $685 on her car and told her she was going to have to give me something in trade......I enjoyed that. :P

Thanks for this. It saved me "big time"!

For those of you struggling with the screws, an impact screw driver works miracles. I tapped mine with a hammer a few times and they all broke loose no problem.....

Also, the wire cables can be simply pryed from their respective mounts without cutting.

Share this post


Link to post
Share on other sites
I'm having same problem too. On cold start, idle speed is very low or won't run at all without pushing on the accelerator. After warm-up it is ok for the day. Will clean valve and see what happens.

JetPilot

When you say your idle speed is very low, how low is it?

Mines around 600-800 when warmed up and 1400-1600 cold start.

Share this post


Link to post
Share on other sites
I'm having same problem too. On cold start, idle speed is very low or won't run at all without pushing on the accelerator. After warm-up it is ok for the day. Will clean valve and see what happens.

JetPilot

When you say your idle speed is very low, how low is it?

Mines around 600-800 when warmed up and 1400-1600 cold start.

AznMechanic, I have the exact same idle rpm's as you do. Do you condiser 1600 TOO HIGH ? I thought mine was, and am wondering if this is normal ?

thanks !

Share this post


Link to post
Share on other sites
I'm having same problem too. On cold start, idle speed is very low or won't run at all without pushing on the accelerator. After warm-up it is ok for the day. Will clean valve and see what happens.

JetPilot

When you say your idle speed is very low, how low is it?

Mines around 600-800 when warmed up and 1400-1600 cold start.

AznMechanic, I have the exact same idle rpm's as you do. Do you condiser 1600 TOO HIGH ? I thought mine was, and am wondering if this is normal ?

thanks !

Does yours go down after starting the car? The best thing is to let your car idle so it can lubricate before you start riding on your car.

I let mine idle for about 10sec-1min depending on how high the idle is.

Usually after i start my engine its 1600 or 1500 and it goes down to 1300 or 1400 in 20seconds and it goes up and down for a bit.

I currently have Castrol Edge 5W-30 as my engine oil which is synthetic so i was guessing because synthetic oils are thinner and gives better lubrication than dyno oil, it allows the engine to rev high easier because its lubricated better.

Synthetic oils allow better lubrication which reduces more friction which results in lower engine temperature :D

This is my guess XD

Share this post


Link to post
Share on other sites

My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

Hey thanks for the pic, that really helps me!

Share this post


Link to post
Share on other sites

I have a 2003 RX300, problem when starting specially when hot weather. I have seen some post regarding my problem and the majority is cleaning the Idle Control Value and/or throttle body. My question is how to you do the above cleaning, is this where you add chemical with your gas. Please HELP. Thanks.

is that what's wrong with mine? I have an 02 and it will start, rev a tiny bit, and then die. if i rev it, it will be fine.

Share this post


Link to post
Share on other sites

My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

I cleaned the Throttle Body and IACV as directed and even went as far as cleaning the Mass Air Sensor, however my 2000 RX300 is still having the same idling problem. Any suggestions?

Share this post


Link to post
Share on other sites

My Rx300 has exact same problem, so I got read the forum and took out the 2 air intake hoses and the IACV locates right under them. I took out the two screws and cleaned the inside with the throttle body cleaner. The problem went away, so here is the pictures I took (IACV is the black piece with the two screws, one of them has the yellow dot on it).

Hope this help somebody in the future.

me too

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...