Hi everyone, I'm trying to find ways to maximize mileage on my '03 PSD.
Currently getting 16.2 MPG with bone stock unit with a canopy. I would
be OK with losing some power for the everyday commutes and increases
for trailer hauling.Any ideas?

 

You should be happy with 16. My turd 300 gets 12 and don't have nearly the power you have to show for it.

 

ive never seen anything (programmers and such) derating the engine...........usually if u upgrade the tuning u actually get better MPG as long as u stay off the throttle....... but at 16.2 MPG? id just keep the line moving and be happy. That, from what ive read, is on the high of the average side from across the FTE site.......so pat urself on the back.

 

Tire pressure and over all maintenance. I use the cruise control for most of my driving.

 

I average 16 pulling an 18' open car trailer with a new Mustang on it.I think it is all about how the vehicle is set up and maintained and driving habits.Keep the tires inflated,easy starts and stops and keep the RPM's down.My truck w/ the factory 20" wheels only turn's 1725 @65 mph.JFWIW.

 

Two keys to mileage already mentioned but I'll say them again.

Correct tire pressures.

Driving habbits:

• Keep RPM's below 2,000
• Cruise control is not efficient for fuel economy
• Keep boost levels below 6psi when cruising
• Keep pre-turbo EGT's 600-800 when cruising
• Set locking front hubs to Automatic
• Pre-warm enging at least to minimum operating temperature, but avoid excessive idling
• Proper engine maintenance, -clean fuel/air filters -synthetic lubricants
• Don't ride the brakes

One thing that I know helps me is coasting to the next stop. With the ZF6 I just pop it in neutral as I'm coming to the next stop light. My truck will easily coast a 1/4 mile (or more), if I'm coming to a stop or light on a 50mph rural road. I wouldn't expect you automatic folks to do that, but it works nicely with a manual transmission.

A free'er flowing exhaust system helps fuel economy a bit too. Along with some added power.

-Steve

 

I have an 03 also that's been through all of the flashes on the PCM. I currently get 15 in the city and between 18 and 19 on the highway. Speed, boost, RPMs, and EGT's do make a difference. There are also some threads on this site about purchasing fuel from different stations and different cetane levels. I was running Wally World fuel for a while because of the price and recently switched back to the name brand stations (Citgo, Shell, etc.) to see if I get any additional mileage, even 1 extra mile per gallon is a good increase.

 

Forgot one thing, the only exhaust work I've done on mine cutting off the stock muffler and welding up a Magnaflow. Everything is still the stock 3.5 inch tubing, but it sounds just like a 4 inch system and I am definitely flowing some exhaust out of the tail pipe now. I'm also not running any programmer because I want keep my warranty.

 

Is this a typo or are you better off for fuel economy to not use cruise? How come?

 

If you're running fat dumb and happy, (yes, that's a technical term), on a level roadway with no wind, nothing to make your vehicle vary in speed requiring less or more power, then Cruise Control can be better than your right foot.

Also, some people aren't capable of keeping their foot in one position for extended periods. -Again, CC can be advantagous if you're the type to speed up and slow down.

But, CC is a reactive system. As the vehicle decelerates for grade change, (uphill), or wind resistance, (gusts or steady wind), it's already behind time in when as a human you would have seen the hill coming and accelerated to maintain speed or even increase speed on a more level roadway instead of the CC increasing fuel flow well into a hill where it takes more fuel/engine power to accelerate or maintain speed.

Tests have been conducted by Consumer Reports and other independent agencies where using CC in the same vehicle over the same route with the same conditions, can actually make fuel consumption increase by 25%. Most people will see about a 10% increase in fuel use. Some less, some more, given conditions.

Also, CC on extended trips has been proven to have been a factor in drivers falling asleep. (factor, not cause) One less thing they're not doing to keep their mind awake.

I don't have scientific data on this. And I can't quote publications. Just some things I've read over the years. But, I've also conducted some unscientific tests on my own. CC, in my environment, used in the last six vehicles I've owned, is not something I use for better fuel economy. In fact, using it has proven everything I said above. I won't say that I don't use it, but not as often as a lot of other drivers.

-Steve

 

I could believe this...

In addition, I've noticed that the cruise on a diesel seems to be even slower to react then on a gasser. (turbo lag?)

I've also noticed during a long steep downhill sometimes it seems like you get engine brake when the cruise lets off totally and I can see where its best to let the truck 'run' and build up some speed for the ensuing uphill

 

That's the one thing that chaps my *** about my '05, with the cruise set, it might vary 8-9 mph in any kind of hills. It lags 3-4 before it gets downshifted and wound up, then over shoots 4-5 before it gets backed off. My '99 had a chip in it and it was rock steady, very seldom came out of overdrive even towing. Guess what the '05's gonna get!?!

 

My 04 doesn't vary 1 mph with the cruise set. 21.65 mpg hand calculated on a 500 mile run using powerservice maximum mixture. Stock air filter, 3.5x4.0" magnaflow exhaust, EGR unplugged. The only aggravating thing is the torque convertor locking/unlocking at times, but that seems to be at the start of a trip when it's been city driven for quite a while--after 200 or so miles it quits.

 

that speed variance sounds like you need lower gears.

npcc @ what avg speed did you obtain 21.65mpg?

 

That's where thinkin' gets you in trouble, since I run empty more than loaded I thought the 3.73 might be better mileage wise. I get between 15 and 16.5, half highway half city