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Originally Posted by aah78 MPFI cars do not require to be idled for long periods during cold start to reach operating temperature - however.....
if you notice, when you first start your MPFI car after leaving it off over night or a couple of hours, the engine always revs at a higher speed for a short while. during this time, your engine management system pumps in extra fuel into the engine to help it reach optimum operating specifications. after a minute or less, the revs drop down to regular idling speed.
a good time to start driving is when the high revs have dropped to regular idling revs. ofcourse, allow the engine fluids to begin flowing before you start revving hard or you're bound to damage the moving parts.
you can begin driving before the revs settle down but the motion will be jerky as the engine management system conflicts with inputs from the accelerator.
waiting for the revs to settle down also provides enough time for the oil to do its work in lubricating the movie parts.
in very cold temperatures (around and below freezing) its always recommended to let the car warm up for a short period before moving off. this is because as the external temperature drops the engine fluids become more viscous and hence, do not do their lubricating job effectively. driving off immediately in very cold climates will automatically cause your car to jerk & stall - this Very Bad for your car!!!! lots of friction between moving parts... |
very very welll said...in fact i clicked on this thread to give the EXACT SAME ADVICE that u did due to my experience with my mpfi esteem......very well put!!!!!!!
the car when started stays at 1500 rpm and takes about a min to get to 800-900 rpm.....thats when i start driving off...
if i dont wait(sometimes wen im in a hurry) the car stays slotted at 1700 rom even after driving it for a hour.....not exaggerating.....this has got to do something with a hitch in the ecu software that gets confused if we drive off without running in the engine in the morning
one of the ppl has made a very valuable point by talking about the gear change......one minute MAKES A HELL OF A DIFFERENCE in the smoothness and ease of gear shift(esp in slotting it into reverse)