Neither of my other two vehicles with EFI will start up any faster than the video above when it gets down to the single digits. It has nothing to do with the fuel delivery method. Vehicles simply do not crank as fast when they are cold, whether they are carbureted or fuel injected. That was really the whole purpose of the video. No vehicle will run as well in sub zero temps as it does when it is warmer. That is also fact.

I live in the South, so you are right in that I have never experienced temperatures as low as -15. However, it does get down to the single digits in the Winter from time to time. And when it does, my carbureted Ford truck doesn't act much different than my two vehicles with EFI. Of course, I do have to depress the gas pedal once to set the choke on my truck, but everything else is relatively the same. Both vehicles crank over a bit slower, but both vehicles always start without any trouble. Both vehicles will have a faster idle and both take about the same amount of time to reach full operating temperature. I can drive either vehicle away immediately, and neither of them will stall or hesitate when I do.

So either you are wrong or I am an incredible carburetor tuner.



Well you have to use some common sense here, matthew. I see what you are saying, but a modern vehicle with EFI will also have a higher idle speed when it is colder. You can allow either of them to warm up a bit - maybe a minute or two - to get the idle speed down before driving on a slippery road.

 

Just to stir the pot, I've also considered converting my '84 351W (stock 2bbl) to fuel injection. It runs very well, so why would I want to do that?

Heat.

In the summertime, the truck works hard hauling a camper and towing our Jeep. Several years ago, I had some nasty trouble with heat affecting the carb. I'm not sure of the exact sequence of events, but the truck left me stranded twice shortly after working hard, just loafing along. To the best of my guessing abilities, the temperature was still really high under the hood but fuel flow was low, so the fuel had plenty of time to absorb all that extra heat. I suspect it percolated out of the carb. Cough, cough, cough, stranded by the side of the road. One time was on a twisty mountain road, NOT fun. In both cases, all was fine after cooling off for about an hour or so.

From my biased research, I'm pretty sure modern fuels just aren't optimized anymore for carbureted vehicles, with so few on the road. I'm not saying modern fuel is bad, just different from years ago. I've made some modifications to limit heat reaching the carb and the problem has never returned. However, I often wonder just how much of a margin I have, and if the problem will again return.

So that's why I've considered converting to fuel injection. Just one more thing to consider...

 

What modifications did you make?

Originally, these trucks used a carburetor spacer to help keep the carburetor cooler and some vehicles used a hot idle compensator valve to let in extra air to compensate for the richer mixture at idle generated from a hot engine. Also, the thermostatic air cleaner was designed to bring in cooler outside air to the carburetor.

Do you still have these items?

 

 

I'm guessing the aftermarket fuel injection is throttle body ie electric carburetor?

 

The truck never had a hot idle compensator, as far as I know. If there is one, it's part of the (stock) carb. It still has the stock thermostatic air cleaner thingy (with air inlet by the grill). The carb spacer is still there, plus I added a big homemade heat shield that extends out to the sides beyond the carb.

Other mods are detailed in post #6 in this thread, including overkill ducted air from the AC system to cool the exterior of the carb bowl:

https://www.ford-trucks.com/forums/1...l#post16083555


Details of the electric fuel pump here. Please note the fuel pressure regulator was not needed and has been removed for simplicity:

https://www.ford-trucks.com/forums/1...tallation.html


Once again, I'm not intending to hijack this thread. I joined this thread to mention heat and modern fuel chemistry pointing in favor of fuel injection.

 

EFI is way different. The engine needs to make a leat one full revolution possibly 2 if it is using a cam sensor instead of a crank sensor before firing the plugs to orient the computer.
And dist fitted Carb'd vehicles either points or electronic fire as soon as the first in piston hits a compression stroke and the einge should lite off as soon a one pistone has cycled from an intake to compression stroke.. They should under all circumstances start sooner or faster than an EFI equipped engine. Hell back in the day my old 78 T-bird even at -40 would start with hardly more than tap of the ignition switch. and this was not plugged in either

As for cranking speed when cold it should not impact how easy a vehicle starts (except for diesels). There was time when cranking speed was determined by the strength of the driver.
Slower cranking should not impact lighting off time. And again single digits are NOT cold. EFI engines will idle down after less than min even at -40 as long as the computer has not gone wonky at those temps due to the temp sensors reading open which was an issue on the early EFI systems. Once you get actually get cold carb'd vehicles do not idle down after a min or so and can take upwards of 5 mins or more. If carbs operated as well as EFI at cold temps there would be no need for the stove pipe, it serves 2 purposes the mitigation of carb icing (which it won't always do) and provide heat to help keep the fuel from falling out of suspension while the engine warms up to mitigate stumbling and misfires.

No you are not incredible carb tuner as you are not experiencing cold weather. Most any piece of equipment will operate just fine down in to the single digits even stuff mean for warm weather operation will operate quite fine at those temps. When you start kissing that -10°-15°F mark things change in a big way.. And this where the advantage of EFI really starts to shine as it's operation is no different than at 5°. The same can not be said about carb;d vehicles where some warm up time is needed to prevent stalling and stumbling.

Operation at the temps you are talking about should not have any impact on starting or operation..

 

I understand what you are saying, and I thank you for helping me to prove my point: even though they are way different, a vehicle with a carburetor should not be any harder to start in cold weather than a vehicle with EFI.


If a grown man can freeze to death in single digit weather, I would say that is plenty cold.

I puposely sat in a cold parking lot last Winter when it was in the single digits and waited to see how long it would take for the idle speed to automatically drop down to normal in my Wife's 2013 Jeep Patriot. Normal idle at operating temperature is about 750 RPM in PARK, the same as my carbureted truck. Within a minute it automatically idled down to about 1000 RPM and I drove away.

Under those same temperatures (single digits) and within that same amount of time (1 minute), I can drive my carbureted truck away at about the same fast idle speed (1000 RPM) without any trouble.


That is about as logical as me saying something like "if EFI operated as well as carbs at full operating temperature there would be no need for an O2 sensor."

Besides, the EFI vehicles I have seen usually have some sort of throttle body heater to accomplish the same thing.


Oh no? If my truck with a carburetor lights off without a problem in the single digits, what makes you so sure it wouldn't do it at -40, like your old '78 T-bird?


You may be right at -40, or you may not be. I'm not so sure I can believe that your old '78 T-bird can start up faster than EFI at -40, but it needs more warmup time than EFI at -40. That doesn't make much sense. (If the choke can start an engine that cold and keep it running at that extreme temperature, why can't the choke keep the cold engine running when you begin to drive away?) All I know is my truck does not need warm up time at 5 degrees and it does not stall or stumble any more than my EFI vehicles do when I drive away a minute later.

But if what you are saying is somehow true, then that sounds like a pretty even draw to me. And I am still impressed that a such a simple, mechanical device like a carburetor can *almost* match a modern EFI system - with it's computer and all those sensors - at temperatures that low.

 

I understand what you are saying, and I thank you for proving my point: even though they are way different, a vehicle with a carburetor should not be any harder to start in cold weather than a vehicle with EFI.[/QUOTE]

This was never about starting but operation after starting . Try to stay on topic.

A piece of machinery is NOT the human body. A person can die to exposure in temps above freezing also so not only is that statement ridiculous it proves nothing Quit trying to make ridiculous comparisons to prove a point.

Again single digits is NOT that cold and all carbed vehicles should idle down in that time frame at those temps. And NO EFI vehicle I have driven has ever taken that long to idle down in those rather mild temps that is excessively long. And we see those temps and colder basically every single day for nearly 3 months straight. And it has never taken a minute to idle down in an EFI vehicle at those temps. Usually it is 10 to 15 seconds at most.

Not even a close comparison.And like in the AOD kickdown rod thread you do not understand the basic fundamentals and argued a point where you had no clue what you were talking about....
And not all throttle bodys have coolant fed to in them, today it is the exception rather than rule that they have it it was ONLY there to prevent icing.. The stove pipe was used on basically ALL carb applications since the mid late 60's forward to improve cold weather operation. It was not there just to prevent icing like throttle body heaters but to also provide warm air to help keep the fuel from falling out of suspension in cold weather...


To even think it would show a complete lack of understanding. There is a huge difference between single digits and -40. That is like saying my vehicle runs fine with no problems when it is 70°F outside it will run fine when it is 110°F out, Both are equally stupid a statements.
Likely your truck would never even crank over at those temps. At -40 a conventional lead acid battery loses almost 80% of it;s cranking capacity. In the single digits it only loses 20% of it's cranking capacity. At those temps even a marginal battery will do it's job just fine in the single digits, but will fail to even crank at -40. When in arctic and subarctic climes having a good battery that is is still holding at least 90% of it's rated CCA potential is considered the minimum acceptable threshold. That is but one item , when you get to those temps stuff that operates just fine in warmer temps will not at -40, even the smallest faults that would never show up in warmer temps will show up in those temps. And pretty sure most in the lower 48 do not keep their coolant good to -47°F (-44°C) which is considered the shoot for point here. Again a subject you have zero experience with or understanding but seem to think that cause some thing will start at a balmy 5°F it will start at -40

It does not make sense to you cause like the AOD kickdown rod do understand the operational fundamentals.

Again EFI needs 1 or 2 full revolutions to orient the pip for the computer before it can trigger the ignition. Additionally there is more draw on the battery during cranking and before with EFI, this on a battery that already has had it's available capacity severely reduced. At those temps you may only get a few revolutions out of engine before the battery gives up the ghost.. This gives carb'd vehicles a distinct advantage where as soon as the engine starts to turn the ignition system is firing. No wasted cranking to orient the pip for the computer so it knows when to trigger the ignition system...
This was in part of the reason when I was up north in the early 2000's I drove the the old farmer special (78 F100 with no power anything 3 on the tree and a 300 I6) it got cold enough that the coolant that was mixed to -44°C it gelled in the rad... My truck and one other ( carbed chev suburban) were the only ones that started after sitting for a week, none of the EFI vehicles started all needed to be boosted in order to start.


But operation after starting is a whole different matter. EFI vehicles need no engine heat to properly vaporize the fuel, as that is done by the injectors once an EFI vehicle is running drop it in gear and go.
This cannot be done in a carb'd vehicles when it gets really cold as they rely on engine heat to help vaporize the fuel. If you tried to drop them in gear in the same situation as soon as you opened the throttle the intake vacuum drops and what what fuel is in suspension falls out of suspension and the engine will stumble and it can take several minutes before they will drive without stumbling.

The colder it gets the longer a carbed vehicle will stay in high idle.. Unlike EFI whos high idle time is tabled in the ECU and adjusted by engine temp.. With a carb the colder it is out the tighter the bimetallic strip winds up in the choke cap, the tighter it is wound more time and heat is required to unwind it , The amount of heat it gets is fixed (to a point) and does not change, it doesn't get more when it is colder or less when it is warmer out.... , how ever the colder it gets the less heat it will get as more heat is lost from the engine and other components to the surrounding air increasing the warm up time further. This is why I always dump the exhaust heated.exhaust heat assisted choke assemblies in favour of the fully electric ones as they can take a really long to time to come off in extremely cold weather, as they are either fully or partially dependent on heat from the exhaust manifold and this can be impacted by the ambient temps as heat is lost from the exhaust manifold and the tubes running to the choke cap. This is less of an issue in the ones that utilizes the intake crossover heat but it is still an issue to a smaller degree The fully electric choke assemblies have a much more consistent operation as they are only heated by the choke cap heater and the operation remains more or less consistent.

As the temp drops high idle times increase with carbs this a fact based on simple thermodynamics. It can get cold enough where the heat loss is so great the carb never fully comes off high idle this is especially true if the choke cap has no internal heater. To think that a carb'd vehicle will always idle down at the same rate as an EFI vehicles is ridiculous and shows a complete lack of understanding on how these system work again shades of the TV rod thread.

It is also in these reduced temps where the thromastic air cleaner can become a hindrance as they may never open up leading to what essentially is running with the choke on all time with massive increases in fuel consumption, not only do you burn way more fuel at low temps just do to the heat loss at those temps, having the thermostatic air cleaner closed only compounds the issue as it is acting like a choke. It is in these instances that you can cook the cats off a carbed vehicle due to the highly elevated HC content in the exhaust, I have seen this happen on more than one occasion and the pre EFI 460's were notorious for doing this.
Just to give you an idea of the amount heat loss that can be seen at those temps it was not uncommon back in the day to pull the water pump belt and let the engine thermosiphon to cool as it would allow the engine to actually reach near operating temp and provide some cabin heat.

Again you are on about a subject to which you have little functional knowledge or experience and are trying to relate the relatively mild temps you have experiences in across the board.

 

My definition of "plenty cold" is when your boogers freeze.



Popcorn anybody? I'm thinking kettle corn flavor this time...

 

YOU were the one who gave the example of your old '78 T-Bird cranking over faster than EFI in temperatures of -40, Chief. I just indulged you. I have said this to you before in another thread and I will repeat it here: You are the only person here that I know of who can somehow find a way to disagree with someone who agrees with you.


Yes, idle speed *will* come down in 10 - 15 seconds - but not all the way down to normal curb idle speed.

Again, I tried it last Winter for the sole purpose of comparison and my Wife's 2013 Patriot was absolutely not down to normal [full operating temperature] idle in 10 to 15 seconds. When the engine started, fast idle shot up to about 1500 RPM or so for about 10 seconds. It gradually came down to about 1200 RPM and stayed there for almost a minute before it gradually dropped down again to about 1000 RPM. I drove away and came to a stop about 100 feet later and it was so cold that the idle speed was still 1000 RPM. For comparison, normal curb idle speed is about 750 RPM.


The original poster of this thread was asking about installing an aftermarket EFI system. That would be a throttle-body fuel injection system, which means it would *also* need some sort of stove pipe for the same reasons. RIGHT?




I said my truck would start just fine in the single digits, which is the coldest temperatures we get here in the South. You said your old '78 T-Bird could at -40 but then said mine wouldn't at -40 because I wasn't "an incredible carburetor tuner." But that is not really the reason. My tuning may be fine, but the BATTERY would prevent it from starting. With the correct battery rated for -40 temperatures, there is a good chance my truck *will* start fine in those temperatures, maybe even as good as your old '78 T-Bird.


That is interesting. It seems to me that a carburetor *does* have it's advantages.


The original poster of this thread was asking about installing an aftermarket EFI system. That would be a throttle-body fuel injection system, which means it would *also* need some engine heat for the same reasons. RIGHT?


I can go along with most of this. The only problem I see is the fully electric choke. Unlike the stock thermostatic choke [with electric assist], the ones I have seen have no relation at all to actual engine temperature and work on a timer. As a result, they will often come off too fast and sometimes choke the engine when it isn't even needed. If the choke comes off too fast and the engine isn't ready for it, you will absolutely experience stumbling and/or stalling.


I agree in that a carbureted vehicle may not *always" idle down at the same rate for the reasons you mentioned, but that doesn't mean you can't drive it. The idle may be a bit higher, but you can still drive away at the same time as a vehicle with EFI. I suppose that in extreme temperatures such as -40 degrees a carburetor may "stumble" a bit at first, whereas a vehicle with EFI may not. But that doesn't really matter, because - according to you - the vehicle with EFI probably wouldn't even start anyway, whereas a vehicle with a carburetor probably will.

Fair enough?

 

Again that was a reference to the videos posted showing what you though was an example of good cold weather start with carb which it was not it was marginal..... My T bird was an exaple of what a decent cold should be even at much lower temps. And the explanation as WHY it was NOT decent carb;d cold start.... Again try to keep it between the ditches...


That is NOT normal operation for any EFI vehicle I have driven over the last 30 years at those temps. The will be down to curb idle in 10 to 15 seconds at that temp and that is hundreds if not thousands of vehicles. . But it is a jeep so who knows what stupidity Chrysler did they aren't exactly know for reliable cold weather starting even today... . You are using one example with obviously some funky oddball cold start parameters they are using for whatever reason but it NOT necessary most EFI Vehicles DO not do this.

. Many TBI/CFI systems did not use stove pipes or need them again cause the fuel injectors atomize the fuel and are not depending on engine heat to aid in vaporizing the fuel...
In regards to icing it would depend on the design of the throttle body. Ford's CFI used a stove pipe GM's did not. .
Carbs ice on/in the ventures due to the pressure drop. Ford's CFI used a venturi design throttle body theses would ice up in the venturi's that is why the stove pipe was used.
GM's throttle body had no venturi's and straight bores, no venturi no real icing issues no stove pipe. If they would ice it would be at the boundary of the throttle blades where the pressure drops but this is unlikely as the fuel injectors sit above the throttle blades preventing ice build up.. Some EFI throttle body used the coolant to heat them usually because they had a slight venturi in them the 302 did the 460 did not the 302 used coolant heating the 460 did not... Basically no aftermarket throttle body injection system uses a venturi throttle body. So not a stove pipe is NOT needed. If understood the fundamentals why the the stove pipe was used you know this....


And what makes you thin it would ? Do I think my vehicles would operate just fine in 110°F Arizona heat ? Probably most would not as I'm not that arrogant to think they would. The EFI stuff and Diesels (except one that I know would overheat) should not be an issue the rest would be a crap shoot. As they have never had to operate in those temps. I can tell this most of the Yanks that come up here in the winter or end up going up north and bring their own vehicles that are a few years old as soon as temps hit that -15°F mark most have starting issues.the most common being weak batteries. In fact I think every single one that has come here with vehicle more than 5-7 years old has had to replace the battery.. My buddy Mike from SC who was up for a couple years for work purposes the the first day it hit -15°F his 7 year old truck would not start battery failed to crank it over more than once. We get no warning here either we can go from 32° to -15°F or more overnight and vise versa. This is not uncommon especially in the south of the province up north it just goes cold and stays cold for weeks on end.

Yes for extreme cold weather starting all things being equal they will outperform EFI, extreme cold weather operation not so much, where as the computer can compensate for this in EFI systems, the mech systems in a Carb's vehicle can not unless they have been adjusted for it. And even then EFI will still out perform it in terms of operability.

Already answered , and again no it does not...


I can understand your hesitation believe this given fully electric chokes were almost unheard of in the States. These were the final iteration of chokes Ford used on carbs.. They do not work on a timer they are powered all the time. They still use a choke cap but have no external heating source.. The VV 7200 used a fully electric coke. The 2150's used on the 3.8L also used a fully electric choke. The U.S never got these as they were CFI in the states. The feedback YFA's used on the 4.9L were fully electric. This was the pinnacle of the auto chokes used on Ford vehicles. They had far more reliable and consistent operation than the externally heated choke caps of the past...



Again you are not getting this. At milder temps this not an issue. But such is not the case at colder temps and long before -40. You have NEVER operated carb'd vehicle at colder temps yet seem to think that you what it will do. And aren't listening to someone that has been doing for the better part of half a century... As soon as an EFI starts you can drop it in gear and go. You can't do this with a carb'd vehicle. It will behave just like a cold chainsaw as soon as you start it then pull the trigger it bogs as the fuel falls out of suspension till some heat is built up in it. The same thing happens with carb's auto engines. At exactly what temp this happens depends on many factors. Every vehicle is different. And it may not stumble it may just flat out stall and if you had a weak crank due to a marginal battery you just be stuck with no juice left for a restart. Another reason to let the vehicle run till it ramps off high idle, Some vehicles may not have issues pulling away right away till extreme temps others could be much warmer.
Not to mention you do not want to be pulling away in cold weather still on max high idle Unlike EFI that will adjust timing and fuel curves to insure when you brake the engine is not powering the vehicle through them that is in part what they have a BOO switch. Carb vehicles on the other hand are dumb and keep the throttle at the set point till the choke ramps off the high idle cam. You do not move the vehicle till the choke ramps down the high idle in cold weather this is even more critical if the roads are slippery. In fact the owners manuals even stated to wait till the high idle ramps down so regardless what you think, Ford seemed to think different...

 

Matthew and I are "discussing" why a carbureted vehicle will not operate as well at -40 degrees. It's kind of funny if you think about it.


The original poster was asking about replacing his carburetor and installing an aftermarket fuel injection system on his truck. Many people have chimed in on threads very similar to this one that are convinced that a vehicle with a carburetor simply can not compete with EFI when it gets cold. "Cold starts" usually comes up as the primary reason why they think so low of a carburetor. I suspect most people in this forum do not have to deal with temperatures much colder than 5 degrees, let alone -40 degrees.

The fact that my truck with a carburetor can cold start just fine at 5 degrees, and I can drive it away immediately if I like without any problems at all, seems to surprise most people right there. And then along comes matthew, who says that 5 degrees "isn't cold." His old carbureted T-Bird could crank over at -40 just fine without even using a block heater!

So what if a carbureted vehicle *may* need a little extra warmup time before driving away when temperatures get way down into the double negatives. A person who has EFI might pump their fist in a victory over this, but then they will lose their minds when they realize their vehicles often will not even start!


And no, I am not saying a carburetor is "better." I am saying that people really need to stop with this "cold start" nonsense and give carburetors a little more respect.

 

Exactly. Carb;s do not get the respect nowaday cause basically everybody that started driving in the last 20 years has only operated fuel injected vehicles. Like all advancements in the auto industry it has operation of motor vehicle simpler. Hence less skill is required to make it go. That does not mean the old systems that were replaced by newer ones were inferior they replaced to ease motor vehicle operation so the lowest common denominator can drive a motor vehicle.
If step back lets look at what changed. We went from hand cranking to elec starters , from having to manually control ignition advance to distributors doing for us, this for the most part negated the advantage of the hot start also, From non synchromesh crash box transmissions , to syncro'd ones, From manual chokes to automatic ones, from Standard transmissions to Auto's, from manual steering to power steering , from drum brakes to disks, from points to electronic ignition, from Carburetors to EFI. With each advancement a set of skills that needed to be learned and mastered to effectively operate a motor vehicle were removed making it easier for lowest common denominator to do it. This does not mean the older systems were necessarily inferior they just required more skill and knowledge to operate effectively.

Operating a vehicle with a carb requires more knowledge than EFI, EFI is jump in, turn the key and drive. A carb requires the choke to be set and a shot of fuel dumped down the intake. There is a learning curve to know when you can jump in turn the key and drive or when you should wait and let it warm up. There is a learning curve to know when no pumps on the gas pedal are needed or one or two or more are needed.

Just cause something has been superseded does not necessarily mean it was inferior.