Es300 1995 Idle Setting

[Matej]

Maybe you could know, on the Lexus ES300 1995, applied vacuum to dashpot, stop lever screw adjusted to no clearance, should I turn it a little bit more?

Throttle valve is stick at the beginning, I must push it a little bit harder. But only at the beginning. Is this OK? Is it for the idle?

After adjusting stop screw, I adjusted TPS and corrected throttle cable. All based on the information from service manual for 1993 ES300

I was seeking for the solution, my lex is shaking my hands on the steering wheel, when fully warmed up and idling. Too low RPM?

Yes, it is old car, but it is a good one.

Is this RPM level ok?

[George_Jetson]

You should not have adj the throttle stop screw. If possible, try to return it to the original position. It sounds like you have a couple problems.

First, the sticking throttle, Remove the rubber intake tube, and check the throttle blade. It probably has a buildup of dirt around the blade and body. This is restricting the normal airflow into the engine. Get a can of carb cleaner, use a couple rags, and clean off all the dirt.

Second, there is a air idle control valve. This valve is probably dirty, and sticking. This valve is what the ECM uses to control idle speed. Do a search on this forum, there is a lot of information on the idle control, and how to clean it.

[Matej]

You should not have adj the throttle stop screw. If possible, try to return it to the original position. It sounds like you have a couple problems.

First, the sticking throttle, Remove the rubber intake tube, and check the throttle blade. It probably has a buildup of dirt around the blade and body. This is restricting the normal airflow into the engine. Get a can of carb cleaner, use a couple rags, and clean off all the dirt.

Second, there is a air idle control valve. This valve is probably dirty, and sticking. This valve is what the ECM uses to control idle speed. Do a search on this forum, there is a lot of information on the idle control, and how to clean it.

I checked it before this operation. It is pretty clean. I also used throttle cleaner on IAC. Yes, I skimmed all of the topics about this car on this and other forums. I got all the information.

My head is going to explode. Sometimes its shifting smooth, sometimes hard, depends maybe on my foot. When I drive newer car with auto tranny, it is always shifting smooth, regardless of my foot pressure on throttle.

I hope someone solved it.

[George_Jetson]

Try taking the cables off of the throttle body, see if the thottle blade moves smoothly then. You need to isolate what is actually binding. You may have to pull the entire body off to soak it in cleaner, but you must get it to move freely.

As for the IAC, did you spray it with cleaner, or did you take it apart? If may need to be taken apart, but concentrate on the throttle body first Until that is moving correctly, you will not get good throttle control even if the IAC is working correctly.

You did not mention in your post, but have you checked all the vac hoses? Including the PCV? Leaks of un metered air will also cause problems with unstable idle.

The picture in you first post, the arrow is pointing around 750 RPM, that is normal. Are you saying at that speed it is shaking the steering wheel? If so check the plugs/wires/dist cap. What color are the plugs? Can you smell gas in the exhaust? How many miles on the car?

Last the hard shifting, are you talking about between gears? Or just when you move between drive/ neut/ rev?

[Matej]

Try taking the cables off of the throttle body, see if the thottle blade moves smoothly then. You need to isolate what is actually binding. You may have to pull the entire body off to soak it in cleaner, but you must get it to move freely.

As for the IAC, did you spray it with cleaner, or did you take it apart? If may need to be taken apart, but concentrate on the throttle body first Until that is moving correctly, you will not get good throttle control even if the IAC is working correctly.

You did not mention in your post, but have you checked all the vac hoses? Including the PCV? Leaks of un metered air will also cause problems with unstable idle.

The picture in you first post, the arrow is pointing around 750 RPM, that is normal. Are you saying at that speed it is shaking the steering wheel? If so check the plugs/wires/dist cap. What color are the plugs? Can you smell gas in the exhaust? How many miles on the car?

Last the hard shifting, are you talking about between gears? Or just when you move between drive/ neut/ rev?

I'm playing with it the whole day.

Cables off won't help it. PCV is OK, I haven't mentioned that there is no O/D blinking nor Check Engine light. Seems everything is fine, even on Bosch ESI diag, borrowed from one of my neighbours. IAC just sprayed into the hole, not dismounted.

Yes, the car is shaking, more than diesel volkswagen.

Plugs are OK.

Wires - OK

Distributor cap - OK

Yes, checked the exhaust, seems like too much fuel on same amount of air (no black nor blue or very white)

No, between N-D N-R is just a slight kick, but while driving, I put a little pressure on the throttle, 1st-2nd is rough - feel like on manual, when clutch pedal is quickly released. I found the info about TPS, that this mostly affects the sooner/later shifting. This one I adjusted like manual says. Inserted thickness gauge 0.7mm, should be without continuity. 0.35mm should have continuity.

I was at our Toyota reseller for changing fluids, they haven't noticed any faulty.

What would you do?

[camlex]

what about mass air flow meter and hose?

[Matej]

what about mass air flow meter and hose?

Nope. They were measured and checked OK.

[George_Jetson]

I suggest removing the throttle body and soaking it, you really need to get it move freely.

Next I would suggest checking the coolant temp sensor, keep in mind that the computer uses it's own separate sensor. So just because the dash gauge reads normally, the computer sensor could still be bad. A bad sensor could explain the rich mixture.

The next thing to check are the O2 sensors Bank 1 sensor 1 & bank 2 sensor 1. These control the mixture and could also explain the rich condition. I do not think that the MAF is your problem, but it is a good idea to check it thoughtly. Keeping in mind that the sensor is mainly a mechanical device on this year. First make sure the vane moves freely, without sticking. Measure the voltage, +5, grd and signal. The signal should change smothly if you move the vane with your finger. And measure the Air temp sensor (inside the MAF))

Have you done a compression check? And what is the mileage on your car?

[Matej]

I suggest removing the throttle body and soaking it, you really need to get it move freely.

Next I would suggest checking the coolant temp sensor, keep in mind that the computer uses it's own separate sensor. So just because the dash gauge reads normally, the computer sensor could still be bad. A bad sensor could explain the rich mixture.

The next thing to check are the O2 sensors Bank 1 sensor 1 & bank 2 sensor 1. These control the mixture and could also explain the rich condition. I do not think that the MAF is your problem, but it is a good idea to check it thoughtly. Keeping in mind that the sensor is mainly a mechanical device on this year. First make sure the vane moves freely, without sticking. Measure the voltage, +5, grd and signal. The signal should change smothly if you move the vane with your finger. And measure the Air temp sensor (inside the MAF))

Have you done a compression check? And what is the mileage on your car?

146 022 miles, bought in Torronto, Canada.

CTS is OK, like new, measured ohms by manual.

Oil is OK, coolant is OK, ATF is OK, air filter is OK.

O2s don't know if OK, haven'ŧ checked them, but they would show Check Engine? Am I right?

I opened the throttle, It looks that this sticking is from manufacture. Can't clean, it just stuck (little but can feel it) at the beginning.

What is vane?

Second thing is, that my engine is not braking when throttle pedal released with O/D on at highway. RPMs just suddenly fall. When I turn O/D off, they return. Engine braking at L and 2 is working.

[Matej]

I suggest removing the throttle body and soaking it, you really need to get it move freely.

Next I would suggest checking the coolant temp sensor, keep in mind that the computer uses it's own separate sensor. So just because the dash gauge reads normally, the computer sensor could still be bad. A bad sensor could explain the rich mixture.

The next thing to check are the O2 sensors Bank 1 sensor 1 & bank 2 sensor 1. These control the mixture and could also explain the rich condition. I do not think that the MAF is your problem, but it is a good idea to check it thoughtly. Keeping in mind that the sensor is mainly a mechanical device on this year. First make sure the vane moves freely, without sticking. Measure the voltage, +5, grd and signal. The signal should change smothly if you move the vane with your finger. And measure the Air temp sensor (inside the MAF))

Have you done a compression check? And what is the mileage on your car?

I must mention again, that this sticking at the beginning is happening only when vacuum to dashpot is applied. When the vacuum is not applied, it is not sticking.

Maybe this valve openner sticking is stopping or slowing down the dashpot (in case of overvalued pressure??)

I looked at the troubleshooting in manual, it is insane, many things could cause this symptom. On the other hand, many of these electromechanical parts have a certain tolerance, in case that one thing goes wrong, other things will adapt to it.

I think, that this could be caused 60% TPS and 40% some tranny solenoid.

[George_Jetson]

TPS can cause all sorts of problems with accelerating, but without the throttle moving, the voltage should be steady. The MAF should also be fairly steady. I would suggest checking compression, note the color of each plug, and any issues with compression. You should be seeing around 180 psi (not sure what that would translate to kg cm3). If there are any low cylinders pay special attention to the condition of the plug.

Do not worry about the transmission now, focus your attention into getting the engine running correctly.

Do not get overwhelmed by the list of possible causes, you need to check the basics, chances are that you will find the clue that will point to what should be checked next. I think that you are mistaken on how much these engines can adapt, there is a small window of adj, but once it gets out of that window you will notice problems.

[Matej]

TPS can cause all sorts of problems with accelerating, but without the throttle moving, the voltage should be steady. The MAF should also be fairly steady. I would suggest checking compression, note the color of each plug, and any issues with compression. You should be seeing around 180 psi (not sure what that would translate to kg cm3). If there are any low cylinders pay special attention to the condition of the plug.

Do not worry about the transmission now, focus your attention into getting the engine running correctly.

Do not get overwhelmed by the list of possible causes, you need to check the basics, chances are that you will find the clue that will point to what should be checked next. I think that you are mistaken on how much these engines can adapt, there is a small window of adj, but once it gets out of that window you will notice problems.

I only pulled out 3 spark plugs, other 3 are underneath the air intake. What color on the sparkplugs should I see, if there is a wrong compression?

Also found something about torque converter, if damaged, will result in drivability. But also tranny solenoids.

I returned the stop screw to the right position, (applied vacuum to the dashpot and measured 0mm distance between stop lever and stop screw)

Then I set the TPS to right position based on resistance specified in manual.

Then the "kick-down" or throttle cable was adjusted so there is 0-1mm when throttle valve closed (but there is a little slack)

I'll visit the dealer to check the compression, this one I don't see as a DIY.

[George_Jetson]

The plugs should be a very light tan and dry. Black is a indication of too rich, wet is even worse. Most auto part stores carry compression testers. It is a simple procedure. I don't know how much dealers charge per hour over there, but in the states you can buy a very good compression checker for less than 1 hours labor. The procedure is simple, first make sure that the battery is full charged and remove the fuel pump relay. Next remove all spark plugs, note the condition of each plug ie color, and is it dry or wet. The compression tester will have a gauge, with a hose with a fitting that screws into the spark plug hole. You screw the compression tester into one cylinder and then crank the engine for several seconds (with the throttle held open). The gauge will read, and hold the peak pressure.

Note the peak pressure, and then move the gauge to the next cylinder, and repeat the process. The compression should be about 180 psi, but the difference between the highest and lowest reading is the most important thing here. 5% is good ie 15~20 psi. The greater the difference the worse the problem..

This is also a good time for a tune up. You state the plugs are ok? How many miles/kilometers? Were the gaps checked? Very important! I used to not believe that gapping plugs was critical, I do believe it now ( I have several ASE certs, one is the L1 advanced engine diagnostics, I have a little bit experience with this). I assume that you have also measured the resistance of the spark plug wires, along with checking the cap and rotor. Once you check the compression, let us know what the results are.

Now as far as auto transmission go, they are not my strong point. I do know the basics, and I assure you that you will be in a much better position to evaluate the trans after you have figured out why the engine is running poorly. At this point I would just make note of the transmission fluid condition, and make sure that the level is correct.

[Matej]

The plugs should be a very light tan and dry. Black is a indication of too rich, wet is even worse. Most auto part stores carry compression testers. It is a simple procedure. I don't know how much dealers charge per hour over there, but in the states you can buy a very good compression checker for less than 1 hours labor. The procedure is simple, first make sure that the battery is full charged and remove the fuel pump relay. Next remove all spark plugs, note the condition of each plug ie color, and is it dry or wet. The compression tester will have a gauge, with a hose with a fitting that screws into the spark plug hole. You screw the compression tester into one cylinder and then crank the engine for several seconds (with the throttle held open). The gauge will read, and hold the peak pressure.

Note the peak pressure, and then move the gauge to the next cylinder, and repeat the process. The compression should be about 180 psi, but the difference between the highest and lowest reading is the most important thing here. 5% is good ie 15~20 psi. The greater the difference the worse the problem..

This is also a good time for a tune up. You state the plugs are ok? How many miles/kilometers? Were the gaps checked? Very important! I used to not believe that gapping plugs was critical, I do believe it now ( I have several ASE certs, one is the L1 advanced engine diagnostics, I have a little bit experience with this). I assume that you have also measured the resistance of the spark plug wires, along with checking the cap and rotor. Once you check the compression, let us know what the results are.

Now as far as auto transmission go, they are not my strong point. I do know the basics, and I assure you that you will be in a much better position to evaluate the trans after you have figured out why the engine is running poorly. At this point I would just make note of the transmission fluid condition, and make sure that the level is correct.

Compression check seems easy to do. I'll try to look for the tester, or pay a visit to a dealer. I don't know how much, but I post it here? How much in US?

Plugs are dry, a little dark, I should've taken some pics of it.

I see that you have an experience. Really, would you say that adjusting spark plug gap is OK?

I have a new NGK BKR6EP-11 here, waiting for replace, bought them sooner - was a good price on them. I measured the gaps with a slide calliper (0,02mm tolerance), they are perfectly OK.

It has 235000km (around 142000miles). Changed oil, oil filter, ATF (filter last year - wasn't required), coolant, brake fluid, maybe soon I'll drain the powersteering/cooling fan fluid (Dexron II). I'll measure the resistance of spark plug wires, do a compression check. I will change the plugs in march.

How to check cap and rotor? Btw, aren't those supposed to be in a carburated engine?

Tranny was drained and filled twice this year, it was brown, now its more orange (cca 6 litres in tranny + cca 3 litres in reservoir)

Just plz tell me, when adjusting throttle cable (kick-down tranny cable), manual says that there should be a 0-1mm of stopper visible from a rubber boot. But after adjustment, there is still a little slack. And when engine started and fully warmed up, the dashpot moves down resulting in -1mm inside the rubber boot (outside cable) with bigger slack.

What about this?

[George_Jetson]

Compression check seems easy to do. I'll try to look for the tester, or pay a visit to a dealer. I don't know how much, but I post it here? How much in US?

Us you can pick up a gauge from $45 for a decent unit, professional units are more expensive.

Plugs are dry, a little dark, I should've taken some pics of it.

That's good, is there any signficant difference between the 6 of them? IE is one much lighter, or darker?

I see that you have an experience. Really, would you say that adjusting spark plug gap is OK?

Checking the gap is not optional, you must do it, trust me on this one. Some engines are more sensitive to gap than others.

I have a new NGK BKR6EP-11 here, waiting for replace, bought them sooner - was a good price on them. I measured the gaps with a slide calliper (0,02mm tolerance), they are perfectly OK.

It has 235000km (around 142000miles). Changed oil, oil filter, ATF (filter last year - wasn't required), coolant, brake fluid, maybe soon I'll drain the powersteering/cooling fan fluid (Dexron II). I'll measure the resistance of spark plug wires, do a compression check. I will change the plugs in march.

How to check cap and rotor? Btw, aren't those supposed to be in a carburated engine?

I would suggest buying a replacement cap and rotor. That way you will have something to compare it to. If you do not need it, you can always return it if it has not been installed. The wear will be evident, especially if you have the the new one to look at. And carburated engines have no bearing on if it has a dist or not. Later model lexus (ie 94 up) do not have dist

Tranny was drained and filled twice this year, it was brown, now its more orange (cca 6 litres in tranny + cca 3 litres in reservoir)

Just plz tell me, when adjusting throttle cable (kick-down tranny cable), manual says that there should be a 0-1mm of stopper visible from a rubber boot. But after adjustment, there is still a little slack. And when engine started and fully warmed up, the dashpot moves down resulting in -1mm inside the rubber boot (outside cable) with bigger slack.

What about this?

that I would have to look up, cannot do that at this moment.

[Matej]

Compression check seems easy to do. I'll try to look for the tester, or pay a visit to a dealer. I don't know how much, but I post it here? How much in US?

Us you can pick up a gauge from $45 for a decent unit, professional units are more expensive.

Plugs are dry, a little dark, I should've taken some pics of it.

That's good, is there any signficant difference between the 6 of them? IE is one much lighter, or darker?

I see that you have an experience. Really, would you say that adjusting spark plug gap is OK?

Checking the gap is not optional, you must do it, trust me on this one. Some engines are more sensitive to gap than others.

I have a new NGK BKR6EP-11 here, waiting for replace, bought them sooner - was a good price on them. I measured the gaps with a slide calliper (0,02mm tolerance), they are perfectly OK.

It has 235000km (around 142000miles). Changed oil, oil filter, ATF (filter last year - wasn't required), coolant, brake fluid, maybe soon I'll drain the powersteering/cooling fan fluid (Dexron II). I'll measure the resistance of spark plug wires, do a compression check. I will change the plugs in march.

How to check cap and rotor? Btw, aren't those supposed to be in a carburated engine?

I would suggest buying a replacement cap and rotor. That way you will have something to compare it to. If you do not need it, you can always return it if it has not been installed. The wear will be evident, especially if you have the the new one to look at. And carburated engines have no bearing on if it has a dist or not. Later model lexus (ie 94 up) do not have dist

Tranny was drained and filled twice this year, it was brown, now its more orange (cca 6 litres in tranny + cca 3 litres in reservoir)

Just plz tell me, when adjusting throttle cable (kick-down tranny cable), manual says that there should be a 0-1mm of stopper visible from a rubber boot. But after adjustment, there is still a little slack. And when engine started and fully warmed up, the dashpot moves down resulting in -1mm inside the rubber boot (outside cable) with bigger slack.

What about this?

that I would have to look up, cannot do that at this moment.

I see that you have also ES300.

Could you plz take a photo of your throttle cable when engine is cold and not started?

[Matej]

Compression check seems easy to do. I'll try to look for the tester, or pay a visit to a dealer. I don't know how much, but I post it here? How much in US?

Us you can pick up a gauge from $45 for a decent unit, professional units are more expensive.

Plugs are dry, a little dark, I should've taken some pics of it.

That's good, is there any signficant difference between the 6 of them? IE is one much lighter, or darker?

I see that you have an experience. Really, would you say that adjusting spark plug gap is OK?

Checking the gap is not optional, you must do it, trust me on this one. Some engines are more sensitive to gap than others.

I have a new NGK BKR6EP-11 here, waiting for replace, bought them sooner - was a good price on them. I measured the gaps with a slide calliper (0,02mm tolerance), they are perfectly OK.

It has 235000km (around 142000miles). Changed oil, oil filter, ATF (filter last year - wasn't required), coolant, brake fluid, maybe soon I'll drain the powersteering/cooling fan fluid (Dexron II). I'll measure the resistance of spark plug wires, do a compression check. I will change the plugs in march.

How to check cap and rotor? Btw, aren't those supposed to be in a carburated engine?

I would suggest buying a replacement cap and rotor. That way you will have something to compare it to. If you do not need it, you can always return it if it has not been installed. The wear will be evident, especially if you have the the new one to look at. And carburated engines have no bearing on if it has a dist or not. Later model lexus (ie 94 up) do not have dist

Tranny was drained and filled twice this year, it was brown, now its more orange (cca 6 litres in tranny + cca 3 litres in reservoir)

Just plz tell me, when adjusting throttle cable (kick-down tranny cable), manual says that there should be a 0-1mm of stopper visible from a rubber boot. But after adjustment, there is still a little slack. And when engine started and fully warmed up, the dashpot moves down resulting in -1mm inside the rubber boot (outside cable) with bigger slack.

What about this?

that I would have to look up, cannot do that at this moment.

Compression check was done today (yes, Sunday), OK.

Spark plugs a little grey, mechanic said they are perfect, don't need replacing.

Cap and rotor perfect OK, mechanic said.

So I took him for a ride. He felt that shaky idle in neutral, same as in drive.

So he measured the resistances of IAC, checked if rotating (plugged 12V on both directions) - OK.

He also measured coolant temp sensor resistance - OK

Then he went for stopper screw, it was high, yes, the throttle was all the time at idle a little opened - IAC is stepping engine, it has more than 100 openning levels, and ECM could not find the right position for IAC, so it sets the nearest lower. Then the mechanic checked and adjusted the TPS with 0.7mm gauge, set it for infinite resistance and fastened the screws.

Problem caused by throttle lever stop screw. Everything smooth now, very good pre-christmas gift :-) (before I did adjustments to screw, it was higher, I just set it a little lower just like the manual stated, I still can't find out who messed with it, there was yellow painted mark which was scrambled before I did adjustment).

George, just like you said, he also recommended throttle intake and IACV to soak it up with cleaner for a few hours. IACV - intake ending with lots of hoses in it included IAC motor. But told that this is not necessary now, cause it runs fine. Suggested, that sometimes in March would be OK.

He asked for 36€ (3 hours of work) for all this, I gave him 50€.

[George_Jetson]

It's good to hear that you have it fixed. I think auto manufactures really should re-design the idle stop screw. Many people do not realize that on a fuel injected car, it should not be touched, period. It will always be something else that is causing the problem (except when it has already been messed with, and you are just trying to return it to the original position).

Even in the days of carb engines, the throttle screw has limited adj range. If you adj it too far you will mess up the idle transition circuit of the carb, and it would stumble off idle.

[Matej]

It's good to hear that you have it fixed. I think auto manufactures really should re-design the idle stop screw. Many people do not realize that on a fuel injected car, it should not be touched, period. It will always be something else that is causing the problem (except when it has already been messed with, and you are just trying to return it to the original position).

Even in the days of carb engines, the throttle screw has limited adj range. If you adj it too far you will mess up the idle transition circuit of the carb, and it would stumble off idle.

Still somehow it was sticking, well I sprayed carbon cleaner on the throttle valve during movement, until sticking's gone. Yes, George, you were right, now it's not sticking. But as you can see on the photos, it was just a superficial cleaning. The whole intake should be dismounted and cleaned, not just sprayed.

[George_Jetson]

Keep in mind that if the throttle is sticking, most of the problem will be with the throttle shaft where it goes thru the throttle body. The deposites that you see in the throttle bore cause problems, but sticking is not the main one.