Collection of interesting cold idle behaviors, searched.
04-25-16, 02:48 PM
#26
Hopeful Future
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Under normal operation, they would be shut when the car is cold. The thermovalve allows vacuum to shut them when cold and closes off vacuum when warm to allow them to be open.
Cold = closed
Warm = open
It's just there to keep you from molesting the car when cold, you don't need it. If you have proper control of your right foot and have a brain, you don't need it.
Cold = closed
Warm = open
It's just there to keep you from molesting the car when cold, you don't need it. If you have proper control of your right foot and have a brain, you don't need it.
04-25-16, 07:34 PM
#27
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do you have vacuum at the hose when the car is cold? does the diaphragm hold vacuum?
04-25-16, 07:35 PM
#28
If you have one of those hand held devices which creates vacuum you could connect the line from the diaphragm to the item mentioned and you'll see if the diaphragm works as intended. And I believe the diaphragm should cause the plates to the closed position by default. Use the advanced search feature and type in Hailers after you type in double throttle diaphragm and you'll pull up a number of threads related to this issue.
04-26-16, 11:01 AM
#29
You are giving too much credit to the ECU, this is basically an analogue system.
The car has no idea you're driving like an idiot at cold start, the vacuum applied to the throttle plates is there because the thermovalve is cold...it's all based on coolant temp.
When the thermovalve warms up, vacuum is removed, the plates open and all is normal.
I deleted the secondaries years ago and have had zero issues starting/cold driving.
If you disable the system, might as well at least pull the throttle plates (it's only four screws...use an impact driver to loosen) and if ambitious, pull the shaft as well.
Have you checked your primary throttle set up yet...it's bloody crucial.
The FSM details the procedure- basically, the primary plate is always cracked open by a specified amount (this is set by a grub screw/locknut on the linkage side of the body) and the secondaries open progressively as the primary goes past "x" degrees open (again, specs in FSM)...these are purely mechanical adjustments and if wrong, you'll never get the idle right.
The screw on top of the body is an air bypass that can make fine adjustments to idle but only if the base adjustments are correct.
While the body is sitting on the bench/desk/lap, if you're retaining the thermowax, now is really the only, not just the best, time to set it.
Again, a purely analogue system that depends on water temp. The linkage is absurd and I found the setting procedure difficult to grasp at first but some pondering will get you there.
That said, my next go round will see the thermowax deleted as well.
When setting up the throttle body after install, leave the cable disconnected...it's not needed yet and eliminates a variable (improper adjustment). Assuming your linkage is free/non-binding, use the cable wheel, NOT the TPS actuator arm (which is the easy one to reach, I know) to open the plates and let it snap closed...maybe five times. This gives you a resting state position.
Yes, you can ALWAYS force the linkage more closed (like you were doing with the wedged screwdriver) because there is inherent play in the linkage but that's not where the linkage will normally return, so there's no point in adjusting in that setting.
Get this basic stuff right and your car will idle properly.
04-27-16, 03:59 PM
#30
Hopeful Future
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Not exactly, no.
You are giving too much credit to the ECU, this is basically an analogue system.
The car has no idea you're driving like an idiot at cold start, the vacuum applied to the throttle plates is there because the thermovalve is cold...it's all based on coolant temp.
When the thermovalve warms up, vacuum is removed, the plates open and all is normal.
I deleted the secondaries years ago and have had zero issues starting/cold driving.
If you disable the system, might as well at least pull the throttle plates (it's only four screws...use an impact driver to loosen) and if ambitious, pull the shaft as well.
Have you checked your primary throttle set up yet...it's bloody crucial.
The FSM details the procedure- basically, the primary plate is always cracked open by a specified amount (this is set by a grub screw/locknut on the linkage side of the body) and the secondaries open progressively as the primary goes past "x" degrees open (again, specs in FSM)...these are purely mechanical adjustments and if wrong, you'll never get the idle right.
The screw on top of the body is an air bypass that can make fine adjustments to idle but only if the base adjustments are correct.
While the body is sitting on the bench/desk/lap, if you're retaining the thermowax, now is really the only, not just the best, time to set it.
Again, a purely analogue system that depends on water temp. The linkage is absurd and I found the setting procedure difficult to grasp at first but some pondering will get you there.
That said, my next go round will see the thermowax deleted as well.
When setting up the throttle body after install, leave the cable disconnected...it's not needed yet and eliminates a variable (improper adjustment). Assuming your linkage is free/non-binding, use the cable wheel, NOT the TPS actuator arm (which is the easy one to reach, I know) to open the plates and let it snap closed...maybe five times. This gives you a resting state position.
Yes, you can ALWAYS force the linkage more closed (like you were doing with the wedged screwdriver) because there is inherent play in the linkage but that's not where the linkage will normally return, so there's no point in adjusting in that setting.
Get this basic stuff right and your car will idle properly.
You are giving too much credit to the ECU, this is basically an analogue system.
The car has no idea you're driving like an idiot at cold start, the vacuum applied to the throttle plates is there because the thermovalve is cold...it's all based on coolant temp.
When the thermovalve warms up, vacuum is removed, the plates open and all is normal.
I deleted the secondaries years ago and have had zero issues starting/cold driving.
If you disable the system, might as well at least pull the throttle plates (it's only four screws...use an impact driver to loosen) and if ambitious, pull the shaft as well.
Have you checked your primary throttle set up yet...it's bloody crucial.
The FSM details the procedure- basically, the primary plate is always cracked open by a specified amount (this is set by a grub screw/locknut on the linkage side of the body) and the secondaries open progressively as the primary goes past "x" degrees open (again, specs in FSM)...these are purely mechanical adjustments and if wrong, you'll never get the idle right.
The screw on top of the body is an air bypass that can make fine adjustments to idle but only if the base adjustments are correct.
While the body is sitting on the bench/desk/lap, if you're retaining the thermowax, now is really the only, not just the best, time to set it.
Again, a purely analogue system that depends on water temp. The linkage is absurd and I found the setting procedure difficult to grasp at first but some pondering will get you there.
That said, my next go round will see the thermowax deleted as well.
When setting up the throttle body after install, leave the cable disconnected...it's not needed yet and eliminates a variable (improper adjustment). Assuming your linkage is free/non-binding, use the cable wheel, NOT the TPS actuator arm (which is the easy one to reach, I know) to open the plates and let it snap closed...maybe five times. This gives you a resting state position.
Yes, you can ALWAYS force the linkage more closed (like you were doing with the wedged screwdriver) because there is inherent play in the linkage but that's not where the linkage will normally return, so there's no point in adjusting in that setting.
Get this basic stuff right and your car will idle properly.
05-01-16, 11:38 AM
#31
Hopeful Future
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So after a few starts to verify from cold, the idle goes up to about 2.5k each time, then when the car is fully warm, it drops to < 1000. Can anyone verify if this is proof that the thermowax system is working as intended? (as in, is this the rpm range its supposed to be at from a cold start.) Even if i give it gas, it returns to approximately 2.5k when cold.
05-01-16, 02:13 PM
#33
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Mine sits steady at 2.5k on a cold start until its warm then it drops down.
Thermo switch is new, the linkage isnt holding the TB open, Trying to catch this gremlin, I might pull the TB off again and just go from square one, checking the fast idle cam, making sure its right, etc. Because I have no idea what could make the idle 2.5k at a cold start, then suddenly drop to < 1000 when the car is warm. Any ideas I haven't thought of?
Checking TB valve clearance on the primaries, checking the thermowax, checking the cam alignment..thats about all I can think of thats yet to be done.
05-01-16, 02:51 PM
#35
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with the MT TB on there this one doesn't hunt, it just has that 2.5k idle until the cars fully warm. I'm going to probably pull the TB off in an hour or so and just do all of the adjustments in the FSM. However, I have no idea how the hell im supposed to measure the 0.5-0.7mm clearance between the primary throttle plate and the bore that the FSM specifies is supposed to be in range for being normal.
Also, I really hope i dont strip those damn screws on the thermowax. What do you guys recommend going with to take those screws off?
05-01-16, 02:58 PM
#36
Someone just mentioned in another thread that if you fold over electrical tape once that it measures the clearance required. the thickness is basically that of a fingernail.
And before you remove the throttle body once again you might want to see if the AWS/BAC is engaging longer than necessary.
And before you remove the throttle body once again you might want to see if the AWS/BAC is engaging longer than necessary.
05-01-16, 03:28 PM
#37
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Someone just mentioned in another thread that if you fold over electrical tape once that it measures the clearance required. the thickness is basically that of a fingernail.
And before you remove the throttle body once again you might want to see if the AWS/BAC is engaging longer than necessary.
And before you remove the throttle body once again you might want to see if the AWS/BAC is engaging longer than necessary.
for the BAC I guess i'll just pull it off and make sure its good and clean, apply 12v to it and see if it moves? what about the AWS, it pretty much is just the bac right?
05-01-16, 03:47 PM
#38
If they are not stuck open you could just unplug the electrical connector to it. the BAC receives a ground from the ECU thus applying 12 volts won't help. There two wires to it where one supplies 12 volts via the B/W wire and the other wire supplies a pulsing ground from the ECU (L/G wire). The AWS works much the same as the B/W wire supplies voltage to it while the other wire is the trigger wire.
05-01-16, 05:07 PM
#39
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with the MT TB on there this one doesn't hunt, it just has that 2.5k idle until the cars fully warm. I'm going to probably pull the TB off in an hour or so and just do all of the adjustments in the FSM. However, I have no idea how the hell im supposed to measure the 0.5-0.7mm clearance between the primary throttle plate and the bore that the FSM specifies is supposed to be in range for being normal.
Also, I really hope i dont strip those damn screws on the thermowax. What do you guys recommend going with to take those screws off?
Also, I really hope i dont strip those damn screws on the thermowax. What do you guys recommend going with to take those screws off?
i'd also leave the thermowax on, and just set the adjustment, the FSM has you line up a line on the cam, its easy.
if you insist on taking off the thermowax, you should use a JDM screw driver, i know it sounds hilarious, but it actually is real. second choice is a pair of pliers, it works ok. third is just a flat blade screw driver.
05-01-16, 07:17 PM
#40
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if the throttle plate adjustment hasn't been touched, then it is going to be in spec, and you're better off not touching it.
i'd also leave the thermowax on, and just set the adjustment, the FSM has you line up a line on the cam, its easy.
if you insist on taking off the thermowax, you should use a JDM screw driver, i know it sounds hilarious, but it actually is real. second choice is a pair of pliers, it works ok. third is just a flat blade screw driver.
i'd also leave the thermowax on, and just set the adjustment, the FSM has you line up a line on the cam, its easy.
if you insist on taking off the thermowax, you should use a JDM screw driver, i know it sounds hilarious, but it actually is real. second choice is a pair of pliers, it works ok. third is just a flat blade screw driver.
I was planning on setting the adjustment as per the FSM guidelines, it does sound easy. As long as its at room temp, just make sure it aligns with the cam like the pictures say. Easy!
Could a BAC be causing this high idle as well? I wouldnt think so. but since I changed the TB out, I highly doubt it has the exact same problem the other one did. Thermoswitch is brand new, so at this point all I can think of is the BAC causing the idle to be high (2.5k like I said) until the car warms up...or am I just blowing smoke here?
11-14-16, 10:24 AM
#43
I wished I would have found this tread earlier in the season - just my luck to finally make some much needed improvements a week before having to put her into winter hibernation.
The base warm idle RPM speed on my S5 n/a was set way too low, even with the air bypass screw all the way out. That was my fault from when I had to rebuild and swapped out pieces/parts to restore functionality to a non-working, carbon locked S5 intake setup. I removed the throttle body and adjusted the base idle set screw and got the warm idle speed back into the normal range. It took a couple tries and I forgot to check the vacuum lines at the T-connection below the Thermowax, so I was chasing my tail for a while. Then I used the air bypass screw to fine tune the warm base idle speed at 750-800 RPM. I got the TPS reset, but that too was a PITA as it took 4-5 attempts because the engine was cooling off too quickly with air temps at about 50 F during the procedure.
Now the car cold start fast idles @ 2300 RPM and there is no way to bring it down by blipping the throttle as with the BAC. Later in the cold start warm up period, the engine will again begin to hunt, but only between 1200-1400 RPM. The hunting is now for a short period of time and a much narrower RPM range than before. Also every once in a while, while driving the car, it will settle at warm idle at 1200 RPM, blipping the throttle a couple of time will bring it down to 800 RPM.
I know the Thermowax and coolant lines are clear, clean of junk and not air locked. So I want to find and disconnect the BAC to know for sure, but I will most likely with have to take a look at the linkage settings for the Thermowax and adjust that back into range as well, to eliminate the last couple of issues. But she is a lot more friendly during cold warm up now than before.
Thanks to everyone for their thoughts and advice - this was very helpful.
The base warm idle RPM speed on my S5 n/a was set way too low, even with the air bypass screw all the way out. That was my fault from when I had to rebuild and swapped out pieces/parts to restore functionality to a non-working, carbon locked S5 intake setup. I removed the throttle body and adjusted the base idle set screw and got the warm idle speed back into the normal range. It took a couple tries and I forgot to check the vacuum lines at the T-connection below the Thermowax, so I was chasing my tail for a while. Then I used the air bypass screw to fine tune the warm base idle speed at 750-800 RPM. I got the TPS reset, but that too was a PITA as it took 4-5 attempts because the engine was cooling off too quickly with air temps at about 50 F during the procedure.
Now the car cold start fast idles @ 2300 RPM and there is no way to bring it down by blipping the throttle as with the BAC. Later in the cold start warm up period, the engine will again begin to hunt, but only between 1200-1400 RPM. The hunting is now for a short period of time and a much narrower RPM range than before. Also every once in a while, while driving the car, it will settle at warm idle at 1200 RPM, blipping the throttle a couple of time will bring it down to 800 RPM.
I know the Thermowax and coolant lines are clear, clean of junk and not air locked. So I want to find and disconnect the BAC to know for sure, but I will most likely with have to take a look at the linkage settings for the Thermowax and adjust that back into range as well, to eliminate the last couple of issues. But she is a lot more friendly during cold warm up now than before.
Thanks to everyone for their thoughts and advice - this was very helpful.
Last edited by DeaconBlue; 11-14-16 at 10:27 AM.
11-14-16, 10:31 AM
#44
I wished I would have found this tread earlier in the season - just my luck to finally make some much needed improvements a week before having to put her into winter hibernation.
The base warm idle RPM speed on my S5 n/a was set way too low, even with the air bypass screw all the way out. That was my fault from when I had to rebuild and swapped out pieces/parts to restore functionality to a non-working, carbon locked S5 intake setup. I removed the throttle body and adjusted the base idle set screw and got the warm idle speed back into the normal range. It took a couple tries and I forgot to check the vacuum lines at the T-connection below the Thermowax, so I was chasing my tail for a while. Then I used the air bypass screw to fine tune the warm base idle speed at 750-800 RPM. I got the TPS reset, but that too was a PITA as it took 4-5 attempts because the engine was cooling off too quickly with air temps at about 50 F during the procedure.
Now the car cold start fast idles @ 2300 RPM and there is no way to bring it down by blipping the throttle as with the BAC. Later in the cold start warm up period, the engine will again begin to hunt, but only between 1200-1400 RPM. The hunting is now for a short period of time and a much narrower RPM range than before. Also every once in a while, while driving the car, it will settle at warm idle at 1200 RPM, blipping the throttle a couple of time will bring it down to 800 RPM.
I know the Thermowax and coolant lines are clear, clean of junk and not air locked. So I want to find and disconnect the BAC to know for sure, but I will most likely with have to take a look at the linkage settings for the Thermowax and adjust that back into range as well, to eliminate the last couple of issues. But she is a lot more friendly during cold warm up now than before.
Thanks to everyone for their thoughts and advice - this was very helpful.
The base warm idle RPM speed on my S5 n/a was set way too low, even with the air bypass screw all the way out. That was my fault from when I had to rebuild and swapped out pieces/parts to restore functionality to a non-working, carbon locked S5 intake setup. I removed the throttle body and adjusted the base idle set screw and got the warm idle speed back into the normal range. It took a couple tries and I forgot to check the vacuum lines at the T-connection below the Thermowax, so I was chasing my tail for a while. Then I used the air bypass screw to fine tune the warm base idle speed at 750-800 RPM. I got the TPS reset, but that too was a PITA as it took 4-5 attempts because the engine was cooling off too quickly with air temps at about 50 F during the procedure.
Now the car cold start fast idles @ 2300 RPM and there is no way to bring it down by blipping the throttle as with the BAC. Later in the cold start warm up period, the engine will again begin to hunt, but only between 1200-1400 RPM. The hunting is now for a short period of time and a much narrower RPM range than before. Also every once in a while, while driving the car, it will settle at warm idle at 1200 RPM, blipping the throttle a couple of time will bring it down to 800 RPM.
I know the Thermowax and coolant lines are clear, clean of junk and not air locked. So I want to find and disconnect the BAC to know for sure, but I will most likely with have to take a look at the linkage settings for the Thermowax and adjust that back into range as well, to eliminate the last couple of issues. But she is a lot more friendly during cold warm up now than before.
Thanks to everyone for their thoughts and advice - this was very helpful.
01-04-17, 04:52 PM
#45
All good info indeed.
I'm basically in the same boat as Tyblat and Deacon here. Surging while the car is warming up, but fine once it is warm and for it's first minute of cold start. (AWS working)
I also get the intermittent high idle of the car idling between 1200-1500 rpm when coming to a stop. I also found that pushing against the throttle linkage does make the idle drop as well, so I gave cleaning out the Thermowax a go this past weekend. Turns out mine was pretty clean with no gunk, so there wasn't much of a change.
I was out messing around with the car and noticed that if I turn on my AC from the high idle, it'll also drop back down to normal idle (800-ish rpm) Here's a video showing what I mean.
I'm basically in the same boat as Tyblat and Deacon here. Surging while the car is warming up, but fine once it is warm and for it's first minute of cold start. (AWS working)
I also get the intermittent high idle of the car idling between 1200-1500 rpm when coming to a stop. I also found that pushing against the throttle linkage does make the idle drop as well, so I gave cleaning out the Thermowax a go this past weekend. Turns out mine was pretty clean with no gunk, so there wasn't much of a change.
I was out messing around with the car and noticed that if I turn on my AC from the high idle, it'll also drop back down to normal idle (800-ish rpm) Here's a video showing what I mean.
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