Warm up

[rmmaso]

2002 C4S

What's the general feeling about a 5 minute or so warm up of the engine before setting out? Good? Bad? Of no consequence? Everything seems smother with a short warm up but somewhere I recall hearing that just putting it in gear and just taking off is the best thing to do. I'd be interested in any thoughts on it. Thanks.

[1999Porsche911]

2002 C4S

What's the general feeling about a 5 minute or so warm up of the engine before setting out? Good? Bad? Of no consequence? Everything seems smother with a short warm up but somewhere I recall hearing that just putting it in gear and just taking off is the best thing to do. I'd be interested in any thoughts on it. Thanks.

Other than wasting fuel and going nowhere, it makes no difference.

[White987S]

I wait about 11 seconds for the convertible to lower, and then start driving. Keeping the RPM's below 4,000 until the temp gauge tells me the engine is up to operating temperature. I think this is the best and most efficient method.

I think this is best for the cats, MAF sensors, spark plugs, just to name a few. This is also consistent with Porsche's Owner's Manual.

[Lee Quave]

Just letting the “engine” idle doesn’t warm-up the “car” it needs to be driven to bring all the systems up to operating temp. I’ve also read, and it makes since to me, that at idle the RPMs are too low for good circulation of the motor oil.

So I start my car put on my seat belt and drive. To be safe I keep the RPMs below 4000 until my temp gauge reads normal after that it’s good to bring the RPMs to about 7300 at least once or twice a day. :drive:

[CosmosC4S]

Same here, I start the car, and by the time I get in and do what I need to do,

like putting away whatever I'm bringing with me, turn on the radar detector, and buckle up....it's time to go.

It's about a mile from my house thru' the sub-division (speed limit 25) out to the main road,

When I get out on the main road, I drive along normally, and would wait at least about 5-10 mins before I push it hard.

[fastboydave]

You are not supposed to just let your vehicle 'idle' this is not good for the motor. So, i agree with other guys, just get in and drive, keeping it below 4000rpm until up to temp. Remember though, your oil isnt up to temp until well after the water, so dont thrash it too hard for a while........

[demosan]

2002 C4S

What's the general feeling about a 5 minute or so warm up of the engine before setting out? Good? Bad? Of no consequence? Everything seems smother with a short warm up but somewhere I recall hearing that just putting it in gear and just taking off is the best thing to do. I'd be interested in any thoughts on it. Thanks.

I also have a 02 C4S and as others have described, I also start and drive away with no real "warm-up" . Keep RPM's below 3,500 until engine shows up to temp.

Never have had a seal leak or similar problem ( :) ) with my car using this method.

demosan

[KevinMac]

Actually, you should never sit warming up the engine at idle. The best way is to start it up allow the oil pressure to come up, then drive conservatively until warm. Allowing it to idle for long periods of time when cold actually causes oil to get diluted more, since it's running rich and there is more blow bye when cold.

Edited November 6, 2007 by KevinMac

[johnj.moran]

I agree that getting in and driving easy until both the water temp and oil pressure gauge get to a warmed up status is best. I find that the oil is near full operating temperature when the gauge reads about half way between 1 and 2 at idle. The closer to 1 the more fully warmed up the engine oil is.

[pomocanthus]

Why is warming at idle bad for the engine? I don't quite understand the arguments (aside from the wasting gas and going no where :lol: ) Please explain.

[Popolou]

Its not and there's no reason for it other than hype. The idea is that to maintain Porsche's green credentials they 'recommend' driving off asap when starting up and not letting the car idle.

Pop

[Lee Quave]

Why is warming at idle bad for the engine? I don't quite understand the arguments (aside from the wasting gas and going no where :lol: ) Please explain.

It’s not bad for the engine but what you really want to do is warm up the whole car; engine, transmission, tires and suspension and you can’t do that with just idling the engine.

[White987S]

Why is warming at idle bad for the engine? I don't quite understand the arguments (aside from the wasting gas and going no where :lol: ) Please explain.

It’s not bad for the engine but what you really want to do is warm up the whole car; engine, transmission, tires and suspension and you can’t do that with just idling the engine.

Lee Quave is "spot-on" here! Plus, the idling is not good for the cats and costly emission sensors.

[pomocanthus]

If idling is bad for cats and O2 sensors does that imply that while idling, there is incomplete combustion?

[White987S]

If idling is bad for cats and O2 sensors does that imply that while idling, there is incomplete combustion?

Sorry, Pomocanthus, I don't know enought about this to help you.

[fastboydave]

I suggest that as the car runs rich initially at startup from cold (you can smell excess 'fuel' at the exhaust for a while) then if you leave to idle it will take much longer for it to reach temp and hit normal parameters prolonging this 'rich' condition. If you drive away, then it gets 'warm' quicker. Every manufacturer will tell you NOT to let a car idle without a load applied. Think it maybe something to do with carbonising the valves too?

[KevinMac]

I suggest that as the car runs rich initially at startup from cold (you can smell excess 'fuel' at the exhaust for a while) then if you leave to idle it will take much longer for it to reach temp and hit normal parameters prolonging this 'rich' condition. If you drive away, then it gets 'warm' quicker. Every manufacturer will tell you NOT to let a car idle without a load applied. Think it maybe something to do with carbonising the valves too?

I agree the car does run rich on cold statup, it's in open loop mode meaning using a predetermined fuel and spark map. It's not until certain paramaters are met that allows it to go into closed loop mode with dependance on sensor input to actually try and achieve the proper ratios. The more rich blow by produces more contaminates in the oil, not to mention washing the cylinders walls more. The faster you warm the engine up, the quicker the condensation internally boils off. Not to mention a too rich a mixture for a prolonged period of time cause carbon. No myth!

[fastboydave]

I suggest that as the car runs rich initially at startup from cold (you can smell excess 'fuel' at the exhaust for a while) then if you leave to idle it will take much longer for it to reach temp and hit normal parameters prolonging this 'rich' condition. If you drive away, then it gets 'warm' quicker. Every manufacturer will tell you NOT to let a car idle without a load applied. Think it maybe something to do with carbonising the valves too?

I agree the car does run rich on cold statup, it's in open loop mode meaning using a predetermined fuel and spark map. It's not until certain paramaters are met that allows it to go into closed loop mode with dependance on sensor input to actually try and achieve the proper ratios. The more rich blow by produces more contaminates in the oil, not to mention washing the cylinders walls more. The faster you warm the engine up, the quicker the condensation internally boils off. Not to mention a too rich a mixture for a prolonged period of time cause carbon. No myth!

Exactly KevinMac, couldnt have said it better myself! Job done, here endeth the lesson........... But if none of the above believe........ then continue to do what you do and see what happens? Maybe they know better than the automotive manufacturers hey?? ;)

[pomocanthus]

It's not a matter of believing or not; just trying to better understand why.

[1999Porsche911]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

[White987S]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

Hi 1999Porsche911, does the Boxster have a secondary air pump, specifically the 987 Boxster? Thanks.

[1999Porsche911]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

Hi 1999Porsche911, does the Boxster have a secondary air pump, specifically the 987 Boxster? Thanks.

Yup. There have been air pumps in one form or another on cars since the 70's.

[KevinMac]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

Oh really, so what determines exhaust temp. Based on your comment all you have to do is wait for exhaust temps temps to rise. Hate to tell U, exhaust temps will run cooler when rich. You are partially correct, but the coolant temperature sensor controls almost exclusively the amount of fuel enrichment during times of cold running. More rich lower exhaust temps. O2 sensor does not come up to temp, open loop mode. Drive the car under laod, coolant temp comes up faster, sarts running more lean, exhaust temps come up quicker, O2 sensor goes into sending based on temp, and it now is in closed loop mode.

[1999Porsche911]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

Oh really, so what determines exhaust temp. Based on your comment all you have to do is wait for exhaust temps temps to rise. Hate to tell U, exhaust temps will run cooler when rich. You are partially correct, but the coolant temperature sensor controls almost exclusively the amount of fuel enrichment during times of cold running. More rich lower exhaust temps. O2 sensor does not come up to temp, open loop mode. Drive the car under laod, coolant temp comes up faster, sarts running more lean, exhaust temps come up quicker, O2 sensor goes into sending based on temp, and it now is in closed loop mode.

The air injection system pumps air into the exhaust system, bypassing the engine entirely. Your O2 esnors are also electrically heated. Educate yourself on the system and you'll learn how it works. Better yet, hook up your scanner and measure the time it takes the car to go closed loop, both ways.

Once in closed loop, the O2 sensors will override any fuel setting being set because of coolant temperature.

Edited January 17, 2008 by 1999Porsche911

[KevinMac]

As long as your secondary air pump is working properly, the difference in the amount of time it takes to go closed loop with your engine at idle versus driving away is immeasurable. The system will go closed loop in approximately the same amount of time, therefore, eliminating any addition time spent running rich. Therefore, the "running rich" argument is untrue. Open or closed loop is not dependent on engine temperature but on exhaust temperature.

Oh really, so what determines exhaust temp. Based on your comment all you have to do is wait for exhaust temps temps to rise. Hate to tell U, exhaust temps will run cooler when rich. You are partially correct, but the coolant temperature sensor controls almost exclusively the amount of fuel enrichment during times of cold running. More rich lower exhaust temps. O2 sensor does not come up to temp, open loop mode. Drive the car under laod, coolant temp comes up faster, sarts running more lean, exhaust temps come up quicker, O2 sensor goes into sending based on temp, and it now is in closed loop mode.

The air injection system pumps air into the exhaust system, bypassing the engine entirely. Your O2 esnors are also electrically heated. Educate yourself on the system and you'll learn how it works. Better yet, hook up your scanner and measure the time it takes the car to go closed loop, both ways.

I agree the pump bypasses the entire combustion process, so now tell me if the entire combusted mixture is not lean how the exhaust temps go up! Air pump simply dilutes the rich exhaust gasses with more air diluting the hydro carbons in an already burned fuel mixture. Combustion already took place. BTW since the coolant temp has not come up the ECU will not have enough input based on the table to actually make the car run at the proper 14.7 ratio, until the temp has come up. True closed loop mode is when the ECU can make very minor adjustments to the mixture. Otherwords a fully warmed engine, based on the coolant temp, O2 input, air temp, air flow etc. will it be in true closed lop mode where minor adjustments can be made. No one is debating if the O2 sensor is heated or not! But when in true closed loop mode the O2 sensor will have more fuel ratio input then when the engine is cold.

The secondary air pump is strictly an emission device to ward off the rich fuel pollutants. when the engine is cold!

As far as a scan tool your tool measures exhaust temps and exahust emissions? I bet the tool you are talking about only shows the O2 sensor coming up to temps and sending input to the ECU!

So no education needed!