Tuesday, April 28, 2015

Estes Park

The annual Estes Park, YMCA cabin trip with friends of ours was a blast and Troubled Child got to join in the fun.

My wife, daughter, and our friends met up at the YMCA of the Rockies on Thursday night a couple weeks ago. I was away on business travel, returning early Friday morning.

During that time, 14" of snow dumped on the YMCA. I decided to take Troubled Child instead of my Subaru. And, I thought I'd have to use my new snow chains to make it to the cabin.

Fortunately, the drive up was uneventful, the roads were simply wet, and there was no snow until I reached the driveway for our temporary home, the Isabella Bird Cabin.

We had a fun weekend of impromptu snowshoeing behind the cabin, wandering downtown Estes Park, eating well, playing games, roller skating, swimming, crafting, and watching the kids play.

The truck made it up and back with no problems other than vibration from a horribly neglected ujoint.

My EFI tuning continues and, unfortunately, I didn't see much power on the way up or back, but I may have solved some off-idle transition issues.

Thursday, April 23, 2015

Neglected U-Joint

On my drive up to Estes Park for the weekend, I noticed a drivetrain vibration getting worse. The mechanic who serviced the transmission a few months ago mentioned a bad ujoint. That's the understatement of the year.

I pulled the driveshaft and discovered the upper ujoint was flopping around loose. So I removed it and disassembled the end caps.

Instead of finding steel roller bearings and grease, the only thing in one of the caps was coal-black dust and rust. The roller bearings were long gone.

Which explains why the bearing surfaces were severely heat damaged, rusted, and pitted. And why there was a ton of play in the joint resulting in crazy vibration.

The seal had cracked wide open which probably let the grease out and let moisture in, destroying everything. The lower ujoint was ok, but the grease was obviously way too old.

Major shame on me for neglecting to lube the chassis over the last few years. Ugh.

I swapped in a spare driveshaft after installing brand new, heavy duty, greasable ujoints on both ends and lubing the shaft. The vibration is gone; I didn't realize how bad it had gotten.

Time to lube everything else, repack the front wheel bearings, replace axle and transfer case fluids, and perform a bunch of other preventative maintenance...

Tuesday, July 29, 2014

Back on the Trail

I stopped four wheeling about five years ago. Purely by coincidence, I assure you, my daughter just turned 5 years old... Well, after a brief stint as a robot, TC is back on the trail! Here's what I've been up to...

Tuesday, June 24, 2014

TC is a Robot!

TC is now a robot!

Every year Sparkfun Electronics hosts the Autonomous Vehicle Competition with robots that fly or drive themselves around courses.

The ground robots are usually 1:10 scale RC cars, sometimes larger like 1:5 scale we saw in 2012 or even a go cart that ran in 2013.

This year a few of us from my robotics club, SHARC, got together to enter the very first full size vehicle in the AVC. It was a dream team of some of the brightest tech people I've ever worked with.

I figured if you're going to enter a full size vehicle why not go all out so I volunteered my trail rig. The Jeep was a big hit with the crowd!

You can read more on my robotics blog to find out why we're not crazy or stupid, and see how the Jeep fared in this intense competition.

Read more here.

Wednesday, May 1, 2013

TBI Tuning: Spark

I've pretty well dialed in the VE (fuel) tables with average BLM numbers between 126 and 130 for most cells.

BLM is Block Learn Mode and basically indicates how much fuel the computer is adding or subtracting versus what's called for in the VE table. Low numbers suggest rich condition, high numbers suggest lean condition.

Earlier this week I worked on adjusting timing, starting with Bill USN-1's timing table on Binder Planet. After driving and minor tweaking, the part throttle timing appears to be pretty good, now.

Two issues remain. Sudden WOT from idle/stopped results in popping and stumble. I'm looking at a possible lean condition and/or timing issue.

Second, the vehicle has little power at 30mph (low rpm). Part of the problem is my transmission shift kit refusing to do part throttle downshift at this speed. Transmission linkage seems properly adjusted.

Using a '7747 ECM, $42 ASDU bin, there's the Main SA (Spark Advance) table, but it's modified by several things. There's a table for power enrichment spark advance which shouldn't be needed in my case and may be causing the first problem. There's also an accelerator enrichment (same function as a carburetor accelerator pump) which I've increased slightly to prevent lean out in hopes of preventing the first condition occurring anywhere else.

Finally, I've restored the Warm Bias setting. The Main SA table can be biased, that is, the zero point can be set to a positive number to allow negative SA numbers. The stock ASDU bin has this set to 9.84, in other words, that value is subtracted from any cell in the SA table to get the 'real' value. A value of 9.84 in the table is zero. A value of 19.84 is 10.00.

I had removed this bias and adjusted my timing table down by 9.84. Just in case this is causing problems elsewhere, I reversed this change, adding 9.84 to my SA table, and restoring the 9.84 warm bias value.

I haven't had a chance to test drive yet.

Due to personal reasons I need to take time off from the Jeep and the blog for several days.