I've had many old Chevys with big blocks and small blocks (and carbs) and when they are warm you barely have to touch the key before they will fire up and run smooth - even with an old school starter. Obviously, LS engines are not like this, as are most modern engines. Is there anything I can do to get near this sort of starting performance out of an LS? Currently just using a factory starter on an LM7. Will a high torque gear reduction starter make for faster starts? (I don't really need the extra torque, my CR is stock) I'm also installing a lithium starting battery, which rests at 13.8v for a little more pep in the starter.

I understand some modern vehicles the computer waits for a certain number of revolutions before it will fire. Does the factory LS computer do this? Anyone know which starter spins the fastest?

 

Carb starting faster huh guess I don’t remember that.
EFI you just turn the key and it starts.

carb pump the gas pedal and pray it starts. After the battery is half dead from cranking.

 

Don't get me wrong, I hate carbs with a passion...but I do miss that nice little bump start. I had one that would just keep running (dieseling) when you took out the key almost like nothing happened, had to put it in first gear to kill it. LOL!

I know I'm nitpicking, but I'm trying to put together a truck that I've wanted for a long time, and I have a long list of features I want.

 

something wrong with your combo if it is not starting instantly. All I have to do is bump the key to the start position for an instantaneous start. No holding the key necessary. This is on ALL LS engines in my family-5 in total. Unless your battery is old/weak or has a dead cell inside, or your starter is dragging for some reason, you should NEVER have to hold the key in the start position for more than a split second regardless of if the engine is hot or cold. Do you have any updates to this engine-cam, LT's, CAI, ported heads-and most importantly has it been tuned? Or is this an all stock combination? If it's been tuned... it needs more/better tuning IF it is not a starter or battery issue. ALL of my LS's fire INSTANTLY.

 

Something wrong with your combo if it is not starting instantly.....................

ALL LS starters are " High Torque Gear reduction "
Maybe your fuel pump is not holding line pressure ?

 

I had to use a MSD starter when I did my twin turbo deal on my TA.

HOLY **** that thing spins the engine fast!

 

No, and no, and no. First, a 2000 LM7 did not come with a gear reduction starter. There are also many different aftermarket starters that can give you more than double the cranking power of the OEM starter. (With twice the power draw) Second, there is absolutely nothing wrong with my engine, and it is stock. This is normal starting behavior for a vehicle like this. Any modern vehicle with EFI I've ever started is about the same. Not instant like an old warmed up carb. If you think they are the same you don't understand what I am comparing.

I'm also talking about a warmed LM7, on a 70 degree day, fully charged battery, and a full fuel pump prime. It's not "instant" the way an old carbed truck would be, and they are not this way from the factory. A brand new 2022 does not start like I am describing. I'm sure if I put a carb on an LS I would get the difference I want, but I don't want a carb.

Again, I know I'm splitting hairs, but there is something very satisfying about a key bump so quick you don't even hear the starter vs just a single second of cranking with something else. Like I said, many, if not most EFI vehicles wait a certain number of revolutions to fire the plugs - they could be waiting for sensors, or oil pressure, or who knows what, but this is a thing modern cars do. I do not know if this is something a 2000 LS computer does. It very well could be.

 

Fuel pressure leaking down?.

How long after shutoff do you hold 55 to 60 pounds of pressure??

put a guage on the fuel rail.

 

I repeat: there is absolutely nothing wrong with my engine or fuel system.

 

Carbs have their place on lawn engines. I never seen a carbed engine start faster then a EFI.

I wish my lawn mower that has a carb would start like your carb engines. That turns over about 4-5 revolutions before it fires off.

the few vehicles, boats I’ve owned that had carbs. I’d would worry they would start after setting a little while after running.

 

First world problems.....

 

Uhh... who cares if it takes a revolution or two to fire up??
My 04 stock Tahoe takes maybe a full 2 seconds to start.
Plugs and wires are good.
I don't expect a hit-the-key-and-fires-right-now type of response, nor is it realistic to do so.

 

I know what he's talking about as far as a quick starting carb engine compared to efi, I had many that you would swear the starter never even turned it over and it was running. Literally bump the key and it was running. EFI makes them start easy and fast but not instant like a warmed properly tuned carb engine can do "at times". It's definitely not something I would try to replicate because it's pointless, I can wait the extra half a second for the engine to start.

 

ECM has to figure out where is piston #1 top dead center before firing spark plugs. In order to do that, the cam sprocket has to rotate to get speed pattern lock. That's why the engine has to rotate first and doesn't try to start immediately.

Carburetor doesn't give you the fast start, it's the mechanical distributor that is always sync to engine.

 

I totally get what your asking. A correctly tuned 70’s vehicle will start after a half revolution when warm. The carb works with airflow being pulled through it (vacuum) from the engine vacuum, and it’s instant. Also the distributor didn’t have to wait on syncing from sensors, it just fired when switched voltage was applied and it was turning any at all. Together the fuel/firing duo worked well and was good when everything was tuned correctly and fresh. The carb was (is) designed to work best when up to temp. The fuel enrichment circuitry and air stop (otherwise known as the CHOKE) was (is) decent at cold starts, but not fool proof, especially at very cold temps. Your modern day ECM controlled engines won’t start quite as fast…takes a couple revolutions for the sensors to get the voltage to the ECM to tell it that everything is ok and to get injectors and coils to fire. There’s nothing you can do to eliminate this “delay”. I do know that GM has improved this “delay” about in half, in the last few years as their vehicles that have the engine shut off as the vehicle stops at traffic lights and in any stop and go instance. This has been applied to their full size trucks with V-8’s as well as their inline 4 vehicles and others also. My nephew recently bought a new GMC 1500 with a 5.3 LT engine that shuts off when stopped. It fires back up quicker than previous LS/LT engines, but it’s definitely not starting as quick as the old carbureted vehicles did.

 

This is rubbish.

LS and modern engines start quickly. Get a grip on reality

 

These guys have got it.

Those of us with carb experience, and who have owned properly tuned setups, are well aware that they can (and do) start faster than EFI under certain conditions. The Holley on my Nova is like this - literally a slight bump of the key when the engine is hot, probably half of the time or less than it takes a perfect stock LS1 to start, and the engine is running. Like said above, it's almost as though you didn't even hear the starter engage and barely have to touch the key. Even the Q-jet on my Cutlass, which frankly could use a rebuild at this point to be at its absolute best, will do the insta-start thing within a couple minutes of having been running when it's fully warmed up...and that setup is as "old tech" as it gets for that era, meaning it still has a points distributor and factory type coil. A carb'ed + distributor setup would have to be in a pretty poor state of tuning and/or condition to NOT be able to do this, probably with other serious driveability issues too.

This sort of reminds me of those folks who insist that their 2000-'02 "Ebony" F-body interior is BLACK. It's not, it's actually a very dark charcoal gray, but if you've never seen a car with a truly black interior then I guess you might be compelled to believe that ebony = black in this instance. I owned my '02 Z28 with an Ebony interior right along side my '71 with a true black interior. The difference was quite noticeable. But still, over the years I've seen many folks argue this point and insist that there is no difference (they are objectively incorrect).

Same is true here. Yes, stock LS engines start very quickly, but they don't have the ability to insta-start the same way as a carb'ed + distributor setup can (obviously only under certain conditions and state of tune) for the reasons explained by Che70velle above. I bought two of my LS1s brand new, one of them with literally 3 miles on it, neither one ever started as quickly as an old carb'ed setup under those very specific conditions discussed above.

But, ultimately, I very much agree with this statement:

This obviously matters to the OP otherwise he wouldn't have asked the question, which is fine, but it's not something that really matters to me personally. But I definitely understand what he's referring to.

 

Small engines like that need a few revolutions to prime the carb. They don't hold fuel after sitting for a while like a car carb will do.

My Chevelle and my 69 pickup will start at the mere touch of the key if they've been previously running recently. My GTOs start much slower but almost always start on the first try, I don't mind the small amount of cranking on the LS1 and LS2 as this allows oil pressure to build just a bit before the engine actually fires. My 2015 driver is the same way, cranks a bit before it starts. But it always starts.

If you've never owned or driven a properly tuned carbed engine you have no idea what we are talking about.

The biggest downside to carbed engines is if they sit for a period of time (weeks, months, etc.) they required a certain amount of cranking to refill the fuel bowls on the carb. You can avoid some of this by manually filling the bowls before trying to start or using just a small spray of starting fluid to help it along. Using a carbed car as a daily would never encounter such issues as long as it is kept in good tune.

 

Here is what we are talking about.

This is my Chevelle. I start it in the first few seconds of the video. It starts as soon as I turn the key. As soon as you hear the starter engage it is running.


This is my LS2 GTO starting. It is started in the first few seconds. It cranks just a bit before it fires.

 

tune your gto better, or better battery. it should start faster. but not a big deal