Our rolling, unscientific biofuel experiment has crossed into the great state of Mississippi – rocketing (joke) toward Oxford and the University of Mississippi.

New Orleans on Thursday.

Behind us, New Orleans, where we filled up on B5 biofuel at a station in an industrial district.

We’re still getting around 23 miles per gallon and we’ve traveled about 3,500 miles since this two-week adventure began on July 28.

The engine inside our 30-year-old Scout is running great. Mostly because we haven’t been running higher concentrations of biodiesel fuel.

So… how are we holding up during this grueling marathon of driving, reporting, sleeping, waking up and repeating? We’re making it.

Last night’s camping experience at the KOA West in New Orleans wasn’t very restful. We didn’t realize that the campground is near a railroad track. Three-minute-long whistles from passing trains kept us up. Cody probably got an hour-and-a-half of sleep and I got four or five.

We apologize if our lack of sleep affected our interview this morning with Tulane’s Prof. Douglas Meffert, who talked about a project to build river turbines to power the city’s Lower Ninth Ward.

Weather: Muggy. Sadly, as many of you know, this truck has no working air conditioning.

For breakfast we stopped at Starbucks for pastry and a coffee. That’s the only thing we really had to speak of today.

But we’re meeting my parents for lunch in Jackson this afternoon and we’re looking forward to joining in the Hotty Toddy in Oxford with Ole Miss fans later tonight and Friday. If you’re on campus tomorrow at about 8:30 a.m. CT, come and say hi. We’ll be set up at The Lyceum.

Are you ready????

– Brian

It’s Day Ten of our California-to-Georgia road trip in our biofueled International Harvester Scout.
We’ve paused in Fort Worth, Texas, providing me with an opportunity to review a couple of loaner GPS navigation units that we’ve been testing out.

The Garmin, left, and the Tom Tom GPS units have pleasantries and annoyances.

We have a Garmin nüvi 880 and a TomTom Go 730. While these two aren’t necessarily in the same price range, they both have their strong and weak points.

Let’s take a look at a few of them.

Certainly the more expensive of the pair, the Garmin nüvi 880 comes equipped with a feature set to match its price. One of the nicer features, in theory, is the draggable map view that can be easily accessed by tapping on the map while in driving mode.

It allows you to view your current position from a “top down” perspective, and you can drag the map around to locate a new or alternate destination by tapping.

Unfortunately, this view quickly proved useless for most purposes, largely because of a lack of detail in the map and its difficulty in appropriately labeling what was shown (it refused to label Las Vegas at any zoom level, labeling all the suburbs instead).

We often found ourselves using the iPhone’s Google Maps application to cross-reference; clearly not something you expect to need to do with a high-end GPS at your disposal.

Otherwise, the Garmin interface is fairly well executed, if a bit slow to respond. It’s easy to set your destination and add via points, and there are menu options allowing you to re-order the points either manually or optimally, based on the route.

Automatic day/night color mode selection is handy, and the high resolution display can show a good bit of information alongside the map, although we wished we could add more.

Another driving mode screen shows various data about your trip, such as distance traveled and average speeds (moving and overall).

It also shows your current speed in a large circle, which was handy for us at night because the Scout’s dash lights are broken. This feature would also be nice for use while bicycling, if you’re brave enough to mount such a nice piece of gear on your bike.

Speaking of mounts, the mounting bracket and suction cup for this device are very well designed, and it hasn’t lost its hold on the windshield yet, even through some very bumpy terrain.

We did experience a few misdirections and bad routing choices, one of which caused us to miss the check-in window for our campsite in Roswell, New Mexico, but overall the Garmin has seen more use on the trip.

The TomTom Go 730probably has the more user-friendly interface, but its screen is lower resolution than the Garmin, and the maps don’t look quite as nice in navigation mode. It does a better job of displaying point of interest (POI) information on the map as you move along, however, which can be handy. Also we liked the ability to see the entire route displayed on a map, but there didn’t seem to be a way to zoom in or out in that view.

Our speed and the current speed limit were always displayed on the main screen along with the map, and this information was also customizable, allowing you to choose what info to display. We never noticed any sluggishness with the interface from tap to tap, and the method of searching for your destination by typing was more intuitive than the Garmin’s, requiring fewer taps.

The mounting hardware for the TomTom leaves something to be desired, as the suction cup has fallen off a few times and the power cable plugs into the bottom of the unit, which can interfere with the dashboard if you don’t place it high enough. Occasionally we had difficulty reading the next turn information on the display, as it is somewhat small and unobtrusive. The speaker, however, was loud enough to overcome this problem most of the time, even with our windows down.

Ultimately, both of the units have pleasantries and annoyances.

Certainly our usage hasn’t covered all of the features of either unit, especially those related to managing and updating them with your computer. Hopefully, however, our experiences can help guide you to a better understanding of what you might be getting into.

See you on the road!

– Brian

We’re mobile again and pausing in Winslow, Arizona, after fixing our fuel filter problems.

Cody takes a break from road-side repairs.

Here’s how we spent Sunday in the fine Arizona community of Kingman working to get our 1978 International Harvester back on track to finish our California-Georgia road trip fueled by biodiesel:

After a late night getting the Scout freed from its confines on the road out of Grand Canyon West, we slept in a little and had a nice big breakfast at Denny’s. We then set out on our daily errands and attempted to get the Scout back up to road-trip condition.

Our main task was to get the fuel tank pumped clear of all of the various substances and residues we’d put in it over the past 1,200 miles. We first tried calling various repair shops and truck stops, to no avail. Then we were directed to Great West Truck Center, a large semi truck service shop that was right there in town.

Thanks to the help of Steve and Debbie at Great West, we were able to get the tank pumped with a minimum of hassle. Apparently what was in there smelled a lot like acetone and had a very strange consistency — prime for clogging things!

With that taken care of, we headed across the way to the Flying J to fill up some good old harmless No. 2 diesel, and used their parking lot as a makeshift shop to switch out our tank. After a quick priming of the system, we were up and running comfortably. Success!

Then it was time to clean the two-and-a-half days of desert dust out of the Scout’s interior. We also took the opportunity to change the air filter and the oil, which, from the look of its filter, was something we should have done already. Everything went fairly smoothly here, and the Scout seems much happier for it.

We then had some very delicious Mexican food at Alphonso’s as a last stop before leaving Kingman and heading to Winslow.

Our original plans were to go to Taos, New Mexico, over the weekend, but due to our unexpected troubles we had to cancel those plans and push it straight to Roswell — voted on by CNN.com users among three other choices (ironically including Winslow). Our stop in Winslow is basically aimed at cutting our drive time into more manageable chunks.

We’ll see you Monday at 9:40 a.m. on CNN.com Live, when we’ll show you the odd way we rigged the fuel line to get us out of the Grand Canyon.

- Brian

The old Nissan diesel engine in the Scout had, as of Friday morning,  taken us about 1,200 miles without incident. Unfortunately, the incident we were already wary of happened just as we were attempting to leave the ranch at Grand Canyon West: Our fuel system clogged up.

Our broken down Scout in Grand Canyon West, Arizona.

One of the issues with using biodiesel in high concentrations is its tendency to act as a powerful solvent on the various engine components it touches. This leads to premature breakdown of anything made of rubber, and on top of that, it cleans out your engine and fuel tank of any gunk that might have built up over its life as a diesel.

In our case, we seem to be suffering more from the fact that the previous person to install fuel lines on the Scout decided to use that stretchy surgical plastic tubing, which our biodiesel made short work of. It turned into goo from the inside out, and the goo went straight into our fuel filter.

We thought we were prepared for this. We had enough fuel line of decent quality to replace the surgical tubing. The four spare filters we have with us should have provided an easy way to fix the rest, but we soon found out that they were all the wrong size — much to our chagrin.

Thanks to the extremely helpful staff and maintenance crew (especially Dave), we were able to change the deteriorating fuel lines and do as thorough a cleaning of the fuel filter as we could. Things seemed to be working great. It was time for a big ranch lunch.

After lunch, we set out again to leave, only to make it a few hundred feet before running smack into the same problem. Dave from maintenance towed us to their shop, and we spent another hour or so cleaning the fuel filter and cracking injector lines and wishing and hoping. We left there, fingers crossed, and made it halfway down the road out before the great clog returned again, with a vengeance.

We then rather frantically researched ways to resolve this situation. Our first thought was to join AAA, and we did. As it turns out, they refuse to tow from where we are. A nice waste of time, effort and money that was. The only local wrecker service we could get in touch with demanded $800 in cash. So instead we got a ride with our new buddy Dave, who was going home by way of the nearest city.

Which brings us, eventually, to our current locale: a motel in Kingman, Arizona. We have a new mission now, which is to get the Scout running again ASAP. We desperately need to find a new fuel filter, and we’ll probably have to rent a car to do it.

Though this turn of events is unfortunate, I suppose it’s a good thing that it didn’t happen in the middle of the desert. The road trip must continue!

– Brian