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Throttle Body Coolent lines removal by oldbikeracer
Started on: 10-28-2013 01:01 PM
Replies: 28 (1014 views)
Last post by: Bloozberry on 11-02-2013 06:09 PM
oldbikeracer
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Report this Post10-28-2013 01:01 PM Click Here to See the Profile for oldbikeracerClick Here to visit oldbikeracer's HomePageClick Here to Email oldbikeracerSend a Private Message to oldbikeracerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Here we go again, a little long so read on.. Last week my 87 2.8 Fierro started idling a little high. I got a Check Engine light when idling, it IAC could not set idle. Next thing I did was check for vacuum leaks and found none. Then I decided to pull the IAC and clean it to see if that would help before I replaced it. I found the problem, when I disconnected the wiring connector it the IAC came off in my hand. It had broken off and the threaded parts was still in the throttle body, I could not get it out so I decided to remove the throttle body so I could get at it to remove the broken off piece. The %#^*$ coolant lines are almost impossible to get at to remove them from the throttle body and VERY VERY tight. Now my question, would it adversely affect the running of the car if I removed them and plugged the holes? I know I will have to pull the upper plenum to remove them, but that is no problem as I have new gaskets on hand. I have removed them on L-98 Chevrolet engines in the past and they ran better without hot water going into the throttle body. Thanks for any suggestions.
Mike

[This message has been edited by oldbikeracer (edited 10-30-2013).]

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Report this Post10-28-2013 01:20 PM Click Here to See the Profile for yellowstoneSend a Private Message to yellowstoneEdit/Delete MessageReply w/QuoteDirect Link to This Post
I removed them years ago to no ill effect. I guess in colder climates they're useful...
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Patrick
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Report this Post10-28-2013 01:31 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by oldbikeracer:

The %#^*$ coolant lines are almost impossible to get at to remove them from the throttle body and VERY VERY tight.


Use flare nut wrenches.

 
quote
Originally posted by oldbikeracer:

Now my question, would it adversely affect the running of the car if I removed them and plugged the holes?

No need to plug the holes in the throttle body. (The connections by the thermostat will need to be looped or capped.) I've done this to three 2.8 Fieros now and have had no issues. Might be a problem in a very cold climate.

 
quote
Originally posted by oldbikeracer:

I know I will have to pull the upper plenum to remove them...


Not unless you want to. I removed a set of lines just a couple weeks ago from my '88 Formula by disconnecting and then bending them to slide them out the thermostat side.

You'll have to fab up a new mount for your MAP sensor. I re-used the original after cutting the metal tubes off of it.

[This message has been edited by Patrick (edited 10-28-2013).]

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Blacktree
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Report this Post10-28-2013 03:01 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Like Patrick said, you should try a flare wrench on those fittings. Barring that, you could cut the pipes and use a socket wrench. Makes sure to use a 6-point socket, because a 12-point will probably round them off.

A hacksaw or Dremel tool will liberate the lines from the MAP sensor bracket.

And like Patrick said, you can address the thermostat neck by either capping the fittings, or bending a short piece of hose into a U-shape. Or if you want to get fancy, you can chop the fittings off and weld the holes shut. There was a guy around here who used to do that, for a small fee.
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Report this Post10-28-2013 03:03 PM Click Here to See the Profile for LornesGTSend a Private Message to LornesGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
If Patrick doesn't have a problem then you won't. His climate is definately colder than yours. The lines keep the TB from freezing.
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Patrick
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Report this Post10-28-2013 03:41 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by LornesGT:

If Patrick doesn't have a problem then you won't. His climate is definately colder than yours. The lines keep the TB from freezing.


I've always wondered about that.

It's actually quite mild in Vancouver (which is right on the coast) all year round, but because it can often be cool and damp here in the winter, I've witnessed carburators icing up. You can actually see frost appearing on the outside (and the inside I presume) of the carb. It's the gasoline being sprayed in the carb that allows the carburator to act like a little refrigeration unit.

Unlike a carb or the throttle body on a duke (which has a fuel injector in it), the throttle body on a Fiero's 2.8 engine doesn't have gasoline anywhere near it, so I don't understand the need to keep it warm.

[This message has been edited by Patrick (edited 10-28-2013).]

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Report this Post10-28-2013 04:02 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

I've always wondered about that.

... It's the gasoline being sprayed in the carb that allows the carbutator to act like a little refrigeration unit.

Unlike a carb or the throttle body on a duke (which has a fuel injector in it), the throttle body on a Fiero's 2.8 engine doesn't have gasoline anywhere near it, so I don't understand the need to keep it warm.


THANK YOU!!
This has been my position all along.
I suppose that under certain conditions, that a throttle body (minus gas) can freeze, but my money is on it not happening.

I have yet to see anyone post here (or any other forum) who had a throttle body to freeze after removing the lines. Personally, I think it's more for emissions. Warms the incoming air a bit sooner.
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Report this Post10-28-2013 05:39 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
In hotter climates the throttle body heat may not be necessary, but I wouldn't say it's not needed elsewhere. Keep in mind that air passing through the TB expands and cools causing any humidity in it to condense and potentially freeze. The actual air temperature doesn't need to be freezing for ice to form in the TB.

I've mentioned it before but it bears repeating: I had a multiport fuel injected Ford Expedition that had the throttle plate freeze up after driving about 20 minutes on the highway at 70 MPH because of a faulty heating system. When I took my exit, the throttle stayed stuck forcing me to jam on the brakes and shut the engine off to keep from slamming into the line of cars at the end of the ramp. Before I could figure out why it jammed, the ice melted from the heat of the engine and snapped the throttle closed again. I eventually figured it out when it happened a second time, though I had just enough time to remove the air filter plumbing to watch as bits of ice came flying out when the throttle plate snapped shut again. Yes... It was winter, it was in Canada, and it's not a Fiero, but it scared the crap out of me enough to know that it's not a system that I would delete unless I were certain I wouldn't be driving in conditions that could cause it.
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Report this Post10-28-2013 05:50 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
+1

Car companies want to sell worldwide, so they have to deal with all the extremes. I suppose they had a Fiero dealer in Fairbanks as well as Tucson....the car had to be fit for both. If you never encounter that kind of extreme driving, OK, you may be able to take the lines off your car, but what happens next is on you, not those overworked engineers back in Warren who figured out a solution.

[This message has been edited by Gall757 (edited 10-28-2013).]

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Patrick
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Report this Post10-28-2013 06:31 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Bloozberry:

The actual air temperature doesn't need to be freezing for ice to form in the TB.


That's why I purposely mentioned "cool and damp" in my post, but yes, it certainly bears repeating that it doesn't need to be freezing cold for ice (and problems) to develop in certain weather conditions.

 
quote
Originally posted by Patrick:

... because it can often be cool and damp here in the winter, I've witnessed carburators icing up.

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Patrick
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Report this Post10-28-2013 06:39 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Bloozberry:

Keep in mind that air passing through the TB expands and cools causing any humidity in it to condense and potentially freeze.


Blooz, without getting too technical , what actually causes air to expand and cool (even with no gasoline being sprayed) as it goes through a TB? Is it simply due to a venturi effect as air is sucked past the butterfly valve?

[This message has been edited by Patrick (edited 10-28-2013).]

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Report this Post10-28-2013 06:50 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
For the record, I had a throttle body freeze over in my 1973 Volkswagen Bus... in ~35 degree weather in South Florida during the Winter.

I've never had a problem with my Fiero, but I've never removed the system. I think it might be ok to remove it for maintenance reasons... but you won't gain any power by removing it.
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Report this Post10-28-2013 07:05 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 82-T/A [At Work]:

I think it might be ok to remove it for maintenance reasons... but you won't gain any power by removing it.


I removed the coolant lines (on several Fieros) just to gain better access to the distributor, and to perhaps keep the area a little cooler for longer ignition component life (although that might be a stretch).

 
quote
Originally posted by 82-T/A [At Work]:

For the record, I had a throttle body freeze over in my 1973 Volkswagen Bus... in ~35 degree weather in South Florida during the Winter.


1973? Would that be a throttle body or a carburator used back then?

[This message has been edited by Patrick (edited 10-28-2013).]

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FTF Engineering
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Report this Post10-28-2013 08:29 PM Click Here to See the Profile for FTF EngineeringSend a Private Message to FTF EngineeringEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:
what actually causes air to expand and cool as it goes through a TB?


What causes the gas to expand and cool? The expansion comes from the pressure drop across the throttle butterfly, and the resulting temperature change is The Law...

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Report this Post10-28-2013 08:51 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FTF Engineering:




Oh yeah, that helps. You've gotta be an engineer.

Thanks.
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oldbikeracer
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Report this Post10-28-2013 10:42 PM Click Here to See the Profile for oldbikeracerClick Here to visit oldbikeracer's HomePageClick Here to Email oldbikeracerSend a Private Message to oldbikeracerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for all the replies. I will remove the lines tomorrow. The broken threaded piece of the IAC came out fairly easily. I did notice it was aluminum construction so new one will be brass or steel. I thought there would not be a problem here in South Georgia removing the lines. I have done it on several C4 L-98 Corvettes with no problems. Again thanks for the replies.

Mike
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Report this Post10-28-2013 11:02 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Oh yeah, that helps. You've gotta be an engineer.

Thanks.

I realize you're joking, but...

They teach that in Physics 101.
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Patrick
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Report this Post10-28-2013 11:42 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Blacktree:

I realize you're joking, but...

They teach that in Physics 101.


It's been so long since I was in college, I don't remember if I ever took a Physics course! Not everyone enjoys math.
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Report this Post10-29-2013 12:40 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just FYI, he was referring to the Ideal Gas Law. A Google search should turn up lots of info. It does involve some math, though.
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Report this Post10-29-2013 07:34 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

1973? Would that be a throttle body or a carburator used back then?




Haha... sorry.

It was an 1800cc motor that originally came with dual Solex carbs, but when I bought it, it had a single 2-bbl Webber progressive carburetor on it. The carb totally froze over like I've never seen before. The entire air cleaner assembly had frost on the outside, and I had to chip it away to remove it. Once I removed it, the entire inside (and surrounding outside of the "venturi" I guess, was frosted over. Surprisingly, the throttle wasn't stuck or anything. I don't even remember why I was back there, it must have been acting up in order for me to go back there and look.
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Report this Post10-29-2013 08:20 PM Click Here to See the Profile for FTF EngineeringSend a Private Message to FTF EngineeringEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:
You've gotta be an engineer.


Haha! Of course I am!

Yes, it's the ideal gas law and it basically states that there is a fixed relationship between pressure, volume, and temperature of a gas. In the example of air flowing past the butterfly in the throttle body, the volume of the air does not change, but the pressure drops across the butterfly. Since the volume remains constant but the pressure drops, that means the temperature must drop. It's the law.

And "Ignorance of the law is no excuse."

PS - Ever heard the one about the engineer and the guy in the hot air balloon?

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Report this Post10-31-2013 09:55 AM Click Here to See the Profile for Marvin McInnisClick Here to visit Marvin McInnis's HomePageSend a Private Message to Marvin McInnisEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Bloozberry:

In hotter climates the throttle body heat may not be necessary, but I wouldn't say it's not needed elsewhere. Keep in mind that air passing through the TB expands and cools causing any humidity in it to condense and potentially freeze. The actual air temperature doesn't need to be freezing for ice to form in the TB.



Previously posted on PFF ... From FAA data:



This data applies primarily to carbureted aircraft engines, where throttle plate icing is more of a problem, but it applies to the throttle bodies of fuel-injected engines as well. There are three primary causes of temperature drop in an engine's induction system: 1) fuel evaporation, 2) pressure drop through a carburetor's venturi, and 3) the abrupt pressure drop across the throttle plate and IAC pintle. Only the third is significant in the V6 Fieros. Note that icing can (and does) still occur at temperatures of over 100 F (40 C) as long as sufficient water vapor is present in the air!
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Report this Post10-31-2013 10:44 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Mike, I'm just a little further north than you and I had 1 car with the lines removed. There was no problem. GM put those lines there for some reason. Maybe for the far northern reaches of their sales area, but like said above, the V6 throttlebody doesn't have an icing problem due to the location of the fuel spray.

I also wonder that since the Intake Air Temperature sensor is far upstream of the throttlebody, if the heated throttlebody might affect performance in a negative manner by adding some temperature to the air charge. Warm air isn't as dense, so less power is generated at combustion. It might be miniscule, but every little horse helps in a Fiero.
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Report this Post10-31-2013 12:57 PM Click Here to See the Profile for css9450Click Here to Email css9450Send a Private Message to css9450Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Marvin McInnis:

Note that icing can (and does) still occur at temperatures of over 100 F (40 C) as long as sufficient water vapor is present in the air!


Not an automotive example, but I'm thinking back to my days counting hammer blows on pile-driving rigs, where the hammer tended to develop a coating of ice where it exhausts the compressed air from within. Even in the heat of a summer day. Probably more so on humid days if I'm reading your chart correctly.

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Report this Post10-31-2013 03:05 PM Click Here to See the Profile for CarrollesClick Here to Email CarrollesSend a Private Message to CarrollesEdit/Delete MessageReply w/QuoteDirect Link to This Post
In cool humid conditions I would think that the IAC air passage could freeze well before the throttle body butterfly would stick. This would result in poor or no idle.
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I hate those lines and agonized about removing them but in the end kept them. It's humid enough here that I can see throttle body freezing being an issue. I figured if GM thinks I need them then that's good enough for me, at least here in h100% humidity ville!

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Report this Post11-02-2013 10:55 AM Click Here to See the Profile for oldbikeracerClick Here to visit oldbikeracer's HomePageClick Here to Email oldbikeracerSend a Private Message to oldbikeracerEdit/Delete MessageReply w/QuoteDirect Link to This Post
So your Fiero sits out in cold weather over night and the throttle body freezes! How the heck are these hot water lines to it going to prevent that? Under hood heat from the exhaust, etc. would thaw things out faster. It is my understanding that the throttle body coolant lines were simply some engineers idea to help emissions. Why all of a sudden with the implantation of TBI did they become necessary, wouldn't the same problem relate to carbureted engines? We went 80 years with carburetors without having to run coolant through them so why is it so necessary on TBI engines. I have owned several C4 corvettes with L-98 TBI injection and have removed the lines from a few of them with nothing but good results. As I said it seems that under hood temperatures would be sufficient and it takes several minutes for coolant temperatures to heat up enough to make any difference. And you are heating the fuel we all know that cool fuel is more efficient so why heat it? Disregard the somewhat disjointed writing in this post as I have a habit of thinking and writing at the same time. It is in the same category with EGR, more stuff to go bad and no real benefits except slightly reducing emissions to placate the over reaching government mandates. Perhaps some of you guys with big brains can explain it to me in layman's terms without hydro dynamics and a bunch of math.

[This message has been edited by oldbikeracer (edited 11-02-2013).]

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Report this Post11-02-2013 11:10 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by oldbikeracer:

So your Fiero sits out in cold weather over night and the throttle body freezes! How the heck are these hot water lines to it going to prevent that? Under hood heat from the exhaust, etc. would thaw things out faster. It is my understanding that the throttle body coolant lines were simply some engineers idea to help emissions. Why all of a sudden with the implantation of TBI did they become necessary, wouldn't the same problem relate to carbureted engines?




I don't know enough about these systems to say with certainty whether or not the lines were there for improved emissions, or to prevent freezing; however, carburetors did have a system very similar to this.

Most cars from the early 70s through the early 80s had a system called a "THERMAC." I don't know if that's an acronym, or an abbreviation. Essentially, there was a thermostatically controlled valve in the intake. When the engine was cool, this valve would allow suction from the engine intake. The suction would then go to the Thermac Air Sensor... and it gets fuzzy here, since I don't remember exactly in what order or how it works. Essentially though, when the engine is cool, it would open a flap in the air intake that would cause it to suck air past the exhaust manifold, instead of through the normal cold air inlet. This would allow the engine to breath warmer air, assisting in speeding up the warm-up of the engine.

Now, I guess the coolant lines kind of fail at this somewhat... at least for starting up, because the motor would have to be warm before the coolant would be warm. But that said... with the old THERMAC system (also found on the 4 cyl Fieros), the THERMAC would also engage when it was really cold out, allowing the engine to suck in warm air to prevent freezing also during normal operation.

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Report this Post11-02-2013 06:09 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by oldbikeracer:
Perhaps some of you guys with big brains can explain it to me in layman's terms without hydro dynamics and a bunch of math.


Well, I don't know about big brains, nor am I trying to preach... but here it is in easier to understand terms. This isn't a smog related issue, and it's not about when your car is parked over night... it's about when your engine is running and air is flowing through your TB.

The air at any given temperature can only hold just so much moisture, so if you drop the temperature of the air, then under certain conditions the moisture begins to fall out of it as dew or condensation. If you drop the temperature far enough, then the condensation becomes ice or frost. So far, everybody should know about this part.

What some people may not know is that you can cause the temperature of the air to drop in several ways, and one of them is to simply to cause it to expand, or lower it's pressure. That's what happens in a throttle body: the air on the outside of the throttle plate is at a higher pressure than once it passes through the TB where it expands (remember that there is a relative vacuum in the plenum). Since the air expands on the backside of the TB, it also cools and some of the moisture content condenses on the inside of the throat. Under certain temperature and humidity conditions, the moisture will form ice on the inside of the TB. So while you're running down the freeway with the throttle partly open, air is constantly expanding on the backside of the throttle which can cause moisture to continuously condense inside the TB. Under certain conditions that moisture will form into ice and can cause your throttle plate to stick open. No amount of engine heat is going to melt that ice until you can stop the air from flowing through the TB. That leaves you with only one option: shut the engine down at the ignition.

That's what happened to me, and that's what I had to do before any engine heat could melt the ice holding the throttle open. I had the entire length of an off ramp to figure out that my throttle was stuck open, that my brakes were really struggling to stop the car, and that I had to shut the engine off to avoid rear-ending the cars at the end of the ramp. Under almost any other circumstances where I had needed to stop shorter, I don't think I would have been able to react in time to avoid a collision. Hindsight is 20/20 but when something like this happens unexpectedly you waste precious seconds simply going "What the f...?"
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