Well im hearing my bad gas mileage could be because i drive like 10 mile short trips. Somebody reccomended letting the car warm up before driving. How long should i let the car run before i drive it so i wont be driving in open loop?

 

You might be wasting more gas by letting it warm up. Cars usually warm up faster when under a load, so I don't think it would be worth it, unless you wanted the heater warmed up faster.

 

I dont know about your bad gas mileage, but letting your car warm up on short trips like that is a must. In the summer 5 min is plenty but in the winter the car really needs a good 10min. This will keep you from having alot of problems like dirty injectors, engine stuttering, hard starting, bad idling, etc. I woek in a shop and am taking a mechanic course in a Vo-tech and my boss and teacher would cringe hearing that someone dosent let their car warm up. Probably you wont get real good gas mileage because the car is sitting there running but it is well worth it later.

 

I disagree..
Just let oil pressure build, plus a bit, and then drive easy til it's 'warmed up'
Cold weather maybe give it a couple minutes, but 10 minutes is a bit extreme I think..

 

You will need no more than 5 minutes to reach the conditions required for "closed loop".... the key one being coolant temp in the range of 120-140degF (variable). You should hit that within 5 minutes of driving. My approach was to let the car idle for no more than 30-60 seconds, then to drive without lugging the engine or exceding 2,000rpm for the first few minutes.

If all your trips are around 10 miles, be sure to take an extended drive periodically. By using an oil temp guage, it became obvious that it took the oil about twice as long to reach normal operating temperature as it did for the coolant to reach normal temp. A periodic "long" drive, insuring the oil heats fully will help drive off condensates that otherwise would stay in the oil and promote the formation of harmful acids.

 

hmm...well that really sucks for me then. there's no way in hell anyone would be caught warming up their car on this island. I drive 10 miles to and from the university, then a mile to safeway, a mile to work...a LONG trip for me is 30 miles to the track. I get about 16mpg on 92 octane, and that's at $2.20/gal!

 

Somehow, I don't think you have the same cold weather issues in Hawaii that gritter has in Michigan.

 

should I warm my car up for a couple minutes, even though it's 90F outside? not trying to be a dick, just a n00b wondering, hehe.

 

Yes warming up your car is a necessity and your car will love you for it. Trust me when i say that it will help. The warmer it is the less time needed but always give it at least a min. before driving.