We had a great day today at the Grand Canyon, however, we were unable to secure a campsite within the park. We are now on our way south, but we've only made it a bit past Tusayan. We are in the Kaibab national forest, parked just off the graded road a bit over the 1/4 mile minimum distance from the highway (map).

Most forest roads are poorly marked to begin with, and figuring out where it is legal to camp is an exercise usually left to the camper. This close to the Grand Canyon, however, the forest is quite heavily used, and there was a giant sign 1/4 mile from route 64 stating that camping was permitted "past this point." We turned in to the first reasonable pull-out after the sign. At this time of year, it's empty here, and we have the forest to ourselves. With the roads so muddy, we did not want to chance going farther and possibly getting stuck.

We had hoped to make it a bit further south, having gotten ourselves ready to leave the park around 5-ish. However, the accelerator-position surging problem is still with us, and getting worse, and we ended up having to pre-heat the engine with our hydronic system for nearly an hour before we could get the engine started without problems.

The same thing happened this morning when we left Tusayan, and I was able to improve things by using my heat gun to warm up the ECM and the harness going into it. Unfortunately, it was a cheap heat gun, and it gave up its ghost during the process. At any rate, I am now relatively convinced that the throttle position problem is either in the ECM itself, or the harness connector going into it. One of our blog readers suggested I remove this connector and put some dielectric grease in there, which is a great suggestion. We will have Detroit do this when we get to Phoenix -- our experience with removing the extremely-difficult-to-access ECM connectors is that one or more pins will sometimes break during the removal or replacement sequence, and we want to be someplace where they can replace a pin if this happens. Breaking off the wrong pin can completely disable the engine.

We need to stop at the Detroit dealer in Phoenix anyway, since we need to change the oil and filters and pull a sample ASAP due to the dirt ingestion issue. We will also have them check the compression and advise us if we can even run the engine for another 2,000 miles to get it back to Sumner. Subjectively, the engine power has dropped off tremendously, and we are blowing copious amounts of black smoke virtually all the time now. We also now drool about a cup of oil out the airbox drains every time we start the motor after it sits for a night, and it seems like our fuel mileage is dropping. To top it all off, I had conversations with a couple of engine-savvy folks while at the Bus Conversion Gathering, and all seem to think we have "dusted" the engine by running it for so many miles with the air filter bypassed. Consensus is that we need new liners, new rings, and a new turbocharger, all of which require pulling the engine from the frame. I'm nervously awaiting a diagnosis when we get to Phoenix, and dreading the conversation I will have to have with the Infinity Coach people about it if the air intake is to blame.

With any luck it will stay dry tonight, so we can back out of here tomorrow without too much drama. We'll run the preheater on the engine for a good couple hours before we even try to start it this time. We are then heading toward Phoenix by the most direct route, which is via 180 to Flagstaff and then I-17 south to Phoenix. Our flight to Cancun is Friday morning, and we have to be in our "parking spot" by close of business Thursday. A straight run will give us some margin for error in the event the engine problems worsen, and will also give us the time we need to get the dog her shots and all three pets to the kennel.

Louise has posted a nice picture of our lovely digs here in the Kaibab forest, below.