Times Have Changed: Cold Starting

Nope

Nope

Nope

Nope

Its ALL because of multi-port high-pressure electronic fuel injection that can keep the mixture spot-on where it needs to be for any engine temperature, and doesn't depend on fully vaporizing the fuel upstream in the intake manifold. A carburetor has a REALLY hard time keeping the mixture anywhere near optimized in sub-zero temperatures, especially through the starting process where the air flow varies from almost none (cranking) to fairly high (fast idle) in a big hurry. In fact, a carb works by pumping a small puddle of fuel into the manifold before cranking (remember "depress accelerator fully twice and release"?) to aid start up, since it can't possibly add enough fuel during cranking. And once the engine fires, that slug of fuel immediately makes the mixture too rich for a few seconds until it burns out... at which time it *may* go too lean again for a few seconds and the engine may stall if you're not quick enough at fluttering the accelerator pedal to pump more fuel in.

Frankly, I kinda miss that spluttering, snorting, shaking process for the first 30 seconds or so after start-up. Sounds really neat on a big-block v8 :-)

Actually, Steve, yeah, that is one of the factors in the much greater ease of super-cold starts. You live in Texas. I live in Toronto. That alone makes me more qualified to comment on it than you (which is hardly a fair exchange: You get to have barbecues and mow your lawn in the middle of January, I get to prattle-on about cold starts. No fair.) What's more, I've got direct and recent (last month) experience with the difference oil weight makes in ability and ease of starting an engine from cold. So, shutchyer mouth, you!

Naw, it isn't. That's a major factor, but certainly not the only one. EFI makes newer vehicles much less tricky to start in the very cold, but other factors apply to new and old cars alike. Oils with lower pour points and better cold pumpability, gasolines that burn cleaner (leaving the spark plugs cleaner so they require less arcover voltage), etc.

DS

While I'm sure that the better oils increase cranking speed and allow the engine to start quicker and idle with less effort, I don't think it has anything to do with the sputter/die/restart that everyone used to know about with carbureted cars.

I live in Toronto. That alone

You can come mow my lawn in January ANYTIME, if you miss mowing lawns so much :-p And maybe you can snort some cedar pollen while you're at it so I don't have to breathe it:-)

Again, I don't really disagree, but I don't think any of that has so much to do with start/sputter/die/restart as EFI does. EFI can meter, vaporize, and evenly distribute fuel FAR better at low temperatures than a carburetor can, while at higher temperatures the difference is far less noticeable. Oil thickness, plug condition, and battery power all matter, but those are second or third-order effects compared to the better fuel control from MPEFI. And there's even a noticeable difference beetween low-pressure throttle-body injected cars and moder high-pressure EFI cars in the "cold" weather we get here in Texas, too. TBI cars often gripe and grumble a lot like carbureted cars because the intake manifolds are "wet" and fuel distribution is very poor in cold temps, whereas MPI cars almost never do.

And I'm telling you, from firsthand experience, that you're wrong on this exact point. With 15w50 Mobil-1 at 20 below (C), it took two or three starts for the engine to stay running. With 5w30 Mobil-1 at 20 below (C) and no other changes, the engine stays running after the first start.

Cranking speed is pretty irrelevant unless an engine is so whipped that the compression pressure leaks past the rings so fast that a high cranking speed is needed. GM proved in the early 1960s that a typical passenger car engine (of the day!) would start at cranking speeds as low as 6rpm.

Fine. I'll accept payment in trips to Kreuz'.

Steve,

I hate to agree with Dan but "always", "all", "none", and "never" are almost always the wrong answer. :>

Art

The problem that I usually had on older cars was the choke. A light tap on the accelerator was needed to set it. Too much would flood it. Then there was the problem of the choke not disengaging when it should, causing a rich air/fuel mix. EFI and AIS stepper motors pretty much eliminated these problems.

One of the most troublesome setups that I had, was a Dodge Caravan with the 2.6 and the Minuki carb. The choke never worked right from day one.

-Kirk Matheson

I think computer controlled fuel injection vs. carburetion is the main reason, but I don't disagree with anything you list above.

Matt

Hell, my old, but reasonably healthy, '82 Mazda 626 will push-start in third gear with somewhere between three and five feet of roll - not a "fast" roll, either, although it does fire even quicker if I can get up some serious speed before popping the clutch - just "moving" - *MAYBE* 1 or 2 MPH, if that. In reverse, a foot or so of roll, at *WAY* below typical walking speed, and a quick clutch-bump is all it takes to fire it up every time. Dunno what the effective RPM is in either case (too lazy to do the math) but whatever the number, it's obviously sufficient for this beast :)

Guess that means it ain't quite whipped yet... :)

This saved my bacon one night at about 3 in the AM... Stopped out in the middle of nowhere to watch the Perseid meteor shower dropping something like 80 streaks per minute before continuing on my newspaper route, and when I decided it was time to go, the starter said "Nah, I wanna stay here and watch the sky-show" (Turned out later to be the starter literally falling apart - One of the two long screws that held the end-caps on it had vibrated loose, allowing some flex, which bound the bearings - minor miracle: The screw that fell out dropped into a groove in the engine cradle, where it rode safely until I found it later that day while I was doing the wrenching to change out the starter.)

Damn fool me had decided to stop at the bottom of a little valley, or maybe gulley would be the better word, in order to screen out the lights on the horizon that were interfering with viewing the meteors - Great view, but both directions were uphill - Figured I was screwed royally. Grunted and heaved and cussed and sweated, and probably strained something, but finally managed to get the front wheels about 2-3 feet up the forward incline before gravity took over and started pushing me back down the slope. Reached in and set the P-brake, sat down and caught my breath, then turned it on, put it in reverse, mashed the clutch, and released the brake. It started rolling back, exactly as expected. It might have managed to hit the dizzying speed of half a mile an hour by the time I bumped the clutch. The front end was still on the slope when the engine fired up.

My '91 Spirit R/T would reliably start by just turning the ignition "on", putting the trans in "Reverse", releasing the parking brake, rolling a few feet down the driveway, then releasing the clutch. Two compressions was all it took.

Yep, that's about what it takes with this beast of mine. As soon as one cylinder even half-assed fires, the engine is running, and keeps on running until I turn off the key. I *LIKE* that in a vehicle. :)

my OLD DATSUN 66 or so had a HAND CRANK that went through a hole in the bumber to the fly wheel...hard starting, tired battery, NP

even had a "dog" to kick it out after it started.......... opened up some of the "oldtimers" eyes in town, when for chuckles, I crank started it...... it was a bullet proof OLD PICKUP......no comfort, no pep, but was reliable for many miles!

even like going mudding.....and easy to find mud here!

I would suggest that the biggest improvement is the elimination of distributors and hence the much improved insulation of the HT path from the coil to the spark plugs.

Wrong, unless you were dumb enough to try to start English or Italian cars somewhere other than Tucson, AZ.

Nope. The insulation of the HT path hasn't changed in over 30 years and many modern engines still use distributors and cold start just fine, as the OP opined.

Steve Lacker hit the nail on the head, it's the advantages of having a fuel injector right above the intake valve that makes the biggest difference.

I've been to Tucson, it gets dark there at night. That rules out the English cars, no?

Maybe the insulation has not changed, but removing the distributor is a major change to the HT path. Removing an air gap and a number of connectors (all of which are affected by dirt and damp) is clearly a significant change.

Many old cars also start just fine, even in cold and wet conditions. They all (well, mostly) started just fine when new. It was always the cars that were marginal in some way that did not start properly.

My point is that your premise that (some) new cars with distributors start fine does not negate the point that the distributor is a significant cause of reduction of HT voltage at the plug, especially in wet conditions and especially with older cars that may have dirty distributor caps.

The rotor air gap increases firing voltage. Comparing spark patterns on an ignition scope, the DIS voltages (all else being equal) are lower, lower ionization voltage and lower voltage across the plug gap compared to a distributor type ignition system. An old tow truck drivers trick when trying to start a stubborn engine in the winter is to pull the coil wire slightly loose from the distributor cap, this increases the voltage output from the coil secondary (greatest gap theory).

Marginal because of neglect, or marginal because of design? Any properly operating ignition system will put out 24 KV from the ignition coil (even breaker points) , that's more than enough spark energy to start an engine no matter how cold it is. It's the intake and fuel system that varied so much that made the difference.

Now you're talking about vehicles that aren't properly maintained. A DIS system is just as subject to not working properly due to damp conditions as a conventional system was, maybe more so if the design of the DIS is such that the ignition coil placement necessitates extremely long spark plug wires such as would be found on the early Chevrolet built 60* V-6 engines (2.8 and 3.1) and dirty distributor caps can be directly compared to dirty DIS coils, hell, I see more problems now with carbon tracking on DIS coils than what used to be 30 years ago on distributor caps. You're not making an 'all things equal' comparison. The first PFI GM engines used the exact same ignition system as the previous years carbed versions (Chevy Camaro for example), the cold start characteristics were night and day, the cold start drivability was night and day, the hot drivability characteristics were night and day, it all had to do with how the fuel was handled. In the winter of 81, we were stacking flooded Chevy Citations and Cavaliers up like firewood, in 82 when both vehicles went TBI injection, the problems for a large part went away as long as people followed the proper cold start procedure, the ignition systems were exactly the same.

Well, it rules out *driving* them. They sometimes don't fail to start after dark there, though.

Have to go with Daniel on this one.. I can remember some research in the

70's having to do with pour points and cold start/running.. and they found at certain temperatures.. they could crank an engine @ 600rpm and it just wouldn't produce enough power to keep itself running with the heavier oils.. darned if I can find a reference to it on the web though.. don't remember who did it either.. but think it was one of the oil companies.