I guess you told me.

Let me say it again, ALL CARS, as far as I know, have some sort of choke function. Notice I didn't say they have a flapper over the venturi. It doesn't have to be a real choke in that sense. In my '93 Talon, it was a fast idle air valve, that allowed more air to pass once it was warmed up, leaning out the mixture a bit. It had MPFI. It also had a Mitsubishi 4G63. I datalogged a couple startups, and didn't see a huge injector pulsewidth that would indicate a "cold-cranking" mode.

Yes, I know the differences in the various fuel injection systems. I've also run and rebuilt plenty of carburetors.

And as for "Fuel injection mixtures are always tuned as perfect as possible", that is false. At anything approaching WOT, your ECU ignores the O2 sensor entirely and just goes off of airflow again. They don't always run in closed-loop mode.

And I did notice that now your story is that the ECU adjusts the mixture without the use of the O2 sensor, when you originally stated that it used the O2 sensor right away. Nice backpedal.

 

To say choke means to choke off airflow, usually to gain a rich mixture. Fuel injection does not choke the airflow to gain a rich mixture. As for your test for cold cranking fuel injection, it only happens DURING cranking. As soon as the engine starts it is done. Anything aproaching WOT? That's wrong, ONLY WOT has a predetermined amount of fuel. And it is predetermined to be as close to the perfect ratio as possible. As for the "fast idle air valve" I can't say I have ever heard of those. I have heard of an idle air control valve (IAC valve) and an AIS motor (automatic idle speed). They perform the same function, bypassing some air around the throttle at idle. On a cold idle, they bypass air to allow more air AND fuel into the engine, raising the idle speed. On low idle, turn on your A/C and you will see your RPM gauge twitch up a bit, that's the IAC adjusting. As for closed loop, the only time they are not in closed loop is when the O2 sensor is too cold or at WOT, I did make confusing posts earlier. Even still, fuel injection in open loop is more precise than any mechanical carburetor could be.
You have worked hands on with these things, but your knowledge ends at the mechanical aspects.

 

I usually let my car's idle smooth out and oil circulate for a minute or two before taking off, and then go extra easy on it until it's really warmed up. If I'm in a real hurry I'll skip the waiting a couple minutes, but I'll still at least wait for the idle to calm down and the oil to circulate a little bit.

As others have mentioned, my there's a huge difference in how my Ralliart drives and feels when it's cold and after it's warmed up. The shifter, clutch, and engine note all feel/sound very noticably rougher when my car is cold, especially the shifter and clutch.

 

It's kind of hard to go wrong following the service manual. If it says to warm it up til the engine oil is ~170F Then there's nothing wrong with that. Based on personal expereince, my EVO drives like crap when anything remotely cold... Then there's the whole "more wear and tear" argument. Either which way, remote start takes care of that for me and doubles as my turbo timer... Then again, idling before turning the car off is another argument in itself... Bottom line, to each is his (or her) own and whatever works for you or whatever your preferences are...

 

Wrong. I rarely went WOT on my GSX. Most of the time, I'd only go 60-75%, per the datalogger and my SAFC. It'd still go into open loop mode. The O2 signal would go from the sinewave form to a basically straight line. As I said before, anything approaching WOT was enough to take it out of closed-loop.
No argument there, although they're closer than you might think, when properly tuned. Tuning is easier on FI, at least.
Hardly. Some of my knowledge may be dated, but that doesn't mean I don't know what I'm talking about.

 

True enough, I don't know everything about FI either. Is it possible some cars DON'T go into open loop near WOT? I am almost positive not every car does what you are saying, but I can't be certain.

 

I suppose it could be possible, but I'm basing much of my knowledge off of tuning/datalogging a Mitsubishi 4G63. Who knows? Engine management may have advanced to the point where it could be in closed-loop at WOT, but I doubt it.

That would suck, anyway. At least in open-loop, you can fiddle with the airflow signal to adjust your mixture at WOT (with an SAFC or similar). If it's in closed-loop the whole time, it would rely on the O2 signal more than the airflow, and you couldn't adjust it manually.

 

Well AT WOT, every car is in open loop. But I was under the impression, that at least some cars are only in open loop right AT WOT, not 15% before it.

 

I really do try to warm mine up, but if I don't have time I drive very relaxed until warm.

 

Just in the morning, and maybe -but rarely- in the afternoon.

 

Remote start is the key. I just hit the button a couple minutes before I leave. It's a beautiful thing.

 

During the winter time in the morning, I let it run for about 10 minutes. Then when I go home for lunch break I let it run for a minute or two. At the end of the day when I leave work I let it run for a minute or two.

Even in warm weather I still get the fluids flowing by sitting for just a minute or two.

 

I let the car warmup for 15-30 seconds unless it is really cold, below 0 degrees F, then I will let it idle for maybe two minutes. Anymore than that and you are wasting gas.

 

Well I don't know about you guys but it is cold as hell when I leave work in the mornings. I warm my car up because if I try to drive it changing gears is really hard. I can tell it's not good for the car. But there is also the little problem of it being cold as $hit outside. I like having a nice warm car to get into when I drive home. Now when I leave for work it's a different story because my car sits in the garage. I'll usually run the car for about 30-60 seconds and them I'm out.

 

i'm **** about temp & driving...i'll let my car warm up until my rpm drops to norm..then i will drive like a grandma until my OIL temp reaches norm...then its full boost from there..hope this helps & screw everyone else this just shows YOU take care of your car