question about mileage during first several minutes of driving a direct injection engine

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Hello, I drive a 2020 F-150 with a 2.7l engine. It has both port and direct injection and if I understand correctly it starts and initially runs on the direct injections primarily/only during the first several minutes of driving. I make several 15 minute trips a week and I notice that for the first 5 minutes or so the 5-minute-mileage history and instantaneous mileage shows a very low number, maybe 12 mpg and then hops up to the mid-20s for the rest of the drive. My trip (tank) mileage will drop .1 mpg for the first several minutes then come back to where it was for the rest of the drive. Driving conditions are the same throughout the drive, only the engine/transmission temp is obviously colder initially, currently about 50F. Additionally, the engine seems to have a slightly uneven idle when I start it, perhaps like a slight misfire, occasionally. One little "putt" every few sections in an otherwise smooth sound.

I am wondering if the things I notice are related and if there is anything that can/should be done. My mileage would be quite a bit better, I think, if 1/3 of the time I was driving I wasn't getting less than 15 mpg, when all the driving is the same. Could my engine be running too rich for some reason? Interested in insights-

Thanks
 
I believe engines run rich when warming up to get up to operational temp quickly and to heat the catalytic converts up to operational temp quickly.
 
Engines run rich when warming up because the fuel doesn't remain vaporized as it travels through the cold intake system.
This condition goes away once warmed up.
I think many engines' management systems idle faster to heat up a cat. A bunch had air blowing into the cat to "fan the flame".
I seem to remember a few heated cats too.

Too bad the wizards who design this stuff (and the impatient public) couldn't have just gone a more sedate route (mellower engine designs) to limit emissions rather than wrangle the dirt of conventional engines.
 
Too bad the wizards who design this stuff (and the impatient public) couldn't have just gone a more sedate route (mellower engine designs) to limit emissions rather than wrangle the dirt of conventional engines.
Could you expand on this? Mellow vs conventional engines?
 
Im going to nerd out here really quick.
When the engine is cold, the direct injection is firing multiple times, particularly after TDC and into the exhaust stroke. This creates very high EGTs which help to bring the catalytic converters up to an efficient operating temperature as quickly as possible. Not fuel efficient, but better for emissions.
 
To Danno: Sure. Vehicle engines delivered ever-increasing power in an unregulated manner. Bigger, faster and more powerful was always OK. This is what I called "conventional".
The pollution these engines spewed out was addressed with control devices like carburetor spacers, air injection units, retarded timing and EGR systems.
Had the industry designed engines which polluted less to start with, the rate of emitting pollutants could've been slowed. This would've bought everybody more time.
I called this "mellow". And yes, such an approach possibly would've crimped the power outputs many crave. This is the "impatient pu0blic" part.
Sorry for the hippy speak but I'd guess you and others got my drift.

How are you with analogies? Dieselgate offers one which is just a subset of what I was grousing about above. Everyone knew diesels are slower to accelerate than gas engines. However, many didn't want to live with that truth. I suppose VW wanted to offer the fuel economy of diesel and the snappiness of a gas engine so they lied big about it.

If everyone involved (sellers and buyers of diesels) simply accepted the fact that diesel vehicles are "mellower" than gas vehicles, the designers could have worked on cleaning the emissions or designing a different engine rather than lying about it.
 
Agree, If the buying public was ok with buying lower powered vehicles, fuel economy could rise tremendously. My old 2001 Honda Civic gets high 30s mpg because it is small, light and has a tiny 1.7 116hp engine. But the markets have spoken. People want bigger, faster, and more gluttonous vehicles.
 
Agree, If the buying public was ok with buying lower powered vehicles, fuel economy could rise tremendously. My old 2001 Honda Civic gets high 30s mpg because it is small, light and has a tiny 1.7 116hp engine. But the markets have spoken. People want bigger, faster, and more gluttonous vehicles.
Just look at all the people driving full size trucks for no real reason.
 
Primary reason is to get the cats up to temp as quickly as possible.
When the engine is cold, the direct injection is firing multiple times, particularly after TDC and into the exhaust stroke. This creates very high EGTs which help to bring the catalytic converters up to an efficient operating temperature as quickly as possible. Not fuel efficient, but better for emissions.

Exactly. That causes a somewhat rough idle for the first minute or two, that's normal. The reasoning behind it is the latest emissions standard, not the DI/PI dual injection. ECU varies DI/PI based on engine temperature, engine speed and load. Giving an example for the complexity of dual-injection mapping (euro-spec Audi EA888 3G), and that's even without temperature:

EA888 3G dual injection mapping.jpg


Engine start and warm-up below 45°C/113°F coolant temp is DI only in this case according to Audi SSP606 (dealer network self-study programme).
.
 
Each ECU programing is different and must be talked about individually. There are no universal standards. In easy terms simplified So form one of my ECU OBDII vehicles during startup the ECU is you just started the engine program. The first thing that happens if the H02s get hot and telling the the ECU "we are hot" so it will this is about 1-2 minutes. The next BIG thing is the coolant temperature must reach the at least 130F (129.9 in my case) with most engine to go into the next set of ECU programing this can vary depending a lot on the ambient and the operating RPM so about lets say oh about 5-10 minutes. Now while all this time from start 1-10 minutes the engine is running at the lowest efficiency for MPG to control emissions which are federal mandated. Unfortunately short drive of less then 30-45 minutes you will be getting the lowest MPG.
My one car 2.5 NA production year 2018 for the first 5-10 minutes and keeping the engine under 2000rpm and hoping I catch every green light and maybe a couple roll through stop sign (no traffic) get 9-17mpg. After a good warm up same route I get 24-28MPG.

I do have a monitor that I constantly watch and can see many ECU monitors and what if technically going on. I have an Ultra Gauge mounted in all my ECU OBDII controlled engines. And there is a lot of PID movements during start up cycle to complete warm cycle going on. The biggest I noticed in all my engines various auto manufacture is the timing and F/I cycling values. I couldn't comment on EGT 's because only one of my monitor engines has a wide ban and EGT monitor sensor. So I am not sure how some are assuming CAT temperatures with out at least an EGT sensor or actually sensors both pre and post CAT?

My various OBDII ECU controlled engines will run a little rough sometimes and other day perfectly smooth during the start up and warm up cycling? My guess is this has to do with the the ignition part called the SPARK PLUGS. HA! My guess is depending on all aspects of the engine operation a few minutes before shut down effects how the next engine cycle and specifically start up cycle will be regarding how smooth the engine will run while the spark plugs are desperately cleaning off the last idling low engine speeds from a full running cycle? And naturally I have seen this on an oscilloscope if only to satisfy my curiosity.
 
To Danno: Sure. Vehicle engines delivered ever-increasing power in an unregulated manner. Bigger, faster and more powerful was always OK. This is what I called "conventional".
The pollution these engines spewed out was addressed with control devices like carburetor spacers, air injection units, retarded timing and EGR systems.
Had the industry designed engines which polluted less to start with, the rate of emitting pollutants could've been slowed. This would've bought everybody more time.
I called this "mellow". And yes, such an approach possibly would've crimped the power outputs many crave. This is the "impatient pu0blic" part.
Sorry for the hippy speak but I'd guess you and others got my drift.

How are you with analogies? Dieselgate offers one which is just a subset of what I was grousing about above. Everyone knew diesels are slower to accelerate than gas engines. However, many didn't want to live with that truth. I suppose VW wanted to offer the fuel economy of diesel and the snappiness of a gas engine so they lied big about it.

If everyone involved (sellers and buyers of diesels) simply accepted the fact that diesel vehicles are "mellower" than gas vehicles, the designers could have worked on cleaning the emissions or designing a different engine rather than lying about it.
I tend to look at this as a regulation issue and a one-upmanship issue.
Class 8 tractor engines 1992 to 2011 had numerous emissions regulations thrown at them to reduce NOx and soot mainly. The manufacturers never had a chance to stabilize technologies before they had to design the next step. I lived through this running a fleet of 100 Tractors.
Same history on cars - early 70s through the early 90s.
The one-upmanship was manufacturers upping the power as part of their advertising.
A quote from Road and Track was that the 0 - 60 mph time got boring in a hurry. Paraphrased of course.
We still see everyone gaga over Tesla 0-60 mph times, but in everyday driving, so over rated IMO.
But public perception, aided by manufacturers is everything, I guess.
 
I'm with you. Don't you think people should've matured a little bit vis' their purchases by now?

That it's "all consumerism" is distressing. Advertising (our biggest industry) appeals to people who seem not to care about what pollutes the Earth.

"Always More" makes us fat and unsatisfied.
 
Hello, I drive a 2020 F-150 with a 2.7l engine. It has both port and direct injection and if I understand correctly it starts and initially runs on the direct injections primarily/only during the first several minutes of driving. I make several 15 minute trips a week and I notice that for the first 5 minutes or so the 5-minute-mileage history and instantaneous mileage shows a very low number, maybe 12 mpg and then hops up to the mid-20s for the rest of the drive. My trip (tank) mileage will drop .1 mpg for the first several minutes then come back to where it was for the rest of the drive. Driving conditions are the same throughout the drive, only the engine/transmission temp is obviously colder initially, currently about 50F. Additionally, the engine seems to have a slightly uneven idle when I start it, perhaps like a slight misfire, occasionally. One little "putt" every few sections in an otherwise smooth sound.

I am wondering if the things I notice are related and if there is anything that can/should be done. My mileage would be quite a bit better, I think, if 1/3 of the time I was driving I wasn't getting less than 15 mpg, when all the driving is the same. Could my engine be running too rich for some reason? Interested in insights-

Thanks
Curious as to what brand and oil spec you are you running?
 
I'm with you. Don't you think people should've matured a little bit vis' their purchases by now?

That it's "all consumerism" is distressing. Advertising (our biggest industry) appeals to people who seem not to care about what pollutes the Earth.

"Always More" makes us fat and unsatisfied
What Earthies are generally missing (a lot like the ethanol and EV arguments) is in the inconvenient details. Untold millions of otherwise good vehicles were TRASHED by those feel good emissions controls mandated before proper engineering and production controls could produce a reliable product. All the Borg Implant emissions kraap added on to ICE sent the vehicles to the scrap heap very prematurely. so all the resources, energy and emissions needed to replace them was MORE than if they had none of that and vehicles lasted 120k miles.

For the older cars the 2D Earthies saw 100 smoking cars and I saw 10 smoking cars and 90 that the engines burned up before before 60k go to scrapyard. Today 2D earthies see an electric car with no smoke and I see 800 lbs of battery waste leaching into my water supply in near future

I suggest that if the engineering and production guys had a fraction of the $$$$$$$$$ wasted on feelgood agendas that we would have arrived environmentally where we are now ...Much SOONER. But this is what the Woodstock hippies swimming in the mud have given us.

The fact you can buy a production car now that makes 700+ horsepower and meets all regs would have happened in any case.
 
What Earthies are generally missing (a lot like the ethanol and EV arguments) is in the inconvenient details. Untold millions of otherwise good vehicles were TRASHED by those feel good emissions controls mandated before proper engineering and production controls could produce a reliable product. All the Borg Implant emissions kraap added on to ICE sent the vehicles to the scrap heap very prematurely. so all the resources, energy and emissions needed to replace them was MORE than if they had none of that and vehicles lasted 120k miles.

For the older cars the 2D Earthies saw 100 smoking cars and I saw 10 smoking cars and 90 that the engines burned up before before 60k go to scrapyard. Today 2D earthies see an electric car with no smoke and I see 800 lbs of battery waste leaching into my water supply in near future

I suggest that if the engineering and production guys had a fraction of the $$$$$$$$$ wasted on feelgood agendas that we would have arrived environmentally where we are now ...Much SOONER. But this is what the Woodstock hippies swimming in the mud have given us.

The fact you can buy a production car now that makes 700+ horsepower and meets all regs would have happened in
How do I delete my post? Sorry for the screwup.
 
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people that are smart with their money buy full size trucks because they hold their value better than anything else. go priced a used truck vs a used car and get back to me.
People that are smart with their money don't buy a $75k+ depreciating asset. They buy a $30k depreciating asset and invest the difference.

No matter what, a vehicle loses value over time, collectors excluded.
VTI, not so much.....
 
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