Workhorse ABS code, revisited

    Hello, all. This is an update of a blog I wrote this past February on a recurring ABS code in a customer Workhorse chassis.
    If you look back you will see that this vehicle has been a problem child and that at last post it looked like it had been fixed. Well, it came back again with the same issue! I don't know how long it was driven before the light set (I don't get to talk to the driver), but this is what we have been dealing with. We will fix a code issue, the repair will survive a test drive, then it will be back with the same code set.
    I had addressed the issue last by switching two wires in the rear harness. These conductors run from one of the rear wheelspeed sensors to the controller at the front of the truck. It always bothered me that this fix solved the problem. The speed sensors generate an AC current which varies in frequency with the RPM of the wheel. I didn't think it would matter which way they are hooked up, since AC current is bi-directional, but when switching the wires seemed to solve the problem, I assumed it had to do with the controller's internal circuit path.
    Anyway, it survived more than one test drive, so I didn't worry about it. After years of repairs, some of these questions of "why" not longer keep you up at night. If it works, it works. Anyway, the vehicle came back a couple of weeks later, same problem, same code. On one of the vehicle's previous visits one of the other guys ran a new twisted pair of wires from the other rear sensor to the controller bypassing the midships plug, and that took care of the intermittent code for that wheel, so I did the same for the other wheel this time. It looks like either the midship connector pins are causing an open, or the harness was handled roughly during factory installation. Since the problem came and went and the plug in question was often manipulated during our diagnosis, it would get my vote.
    Anyway, the truck was in for a PM about a month after this last fix and the ABS light was out, so is looks like we finally have it nailed.
    If anybody else has run into this problem and has any feedback, leave a comment or send an Email and I will post it.
    Thanks.

Here are some assembly hints for the IHC 466 engine.

Here are some assembly hints for the IHC 466 engine. Most are per manufacturer information. They ensure trouble-free, efficient assembly.

• To unhook the injector harness from the valve cover/intake manifold, don't use tools to pry on it. Just squeeze the sides and pull.
• To release the injector harness pass-through from the valve cover, use a 1 3/16, 12 pt socket. Just unhook the harness, put the socket over the pass-through and push.
• If the plastic sediment bowl behind the fuel filter is too tight to remove by hand, use a 1 1/4, 12 pt box wrench.
• Don't install the vibration dampener by pulling it on with bolts. Just warm up the center of the hub to about 250 degrees F and it will slide right on the crank nose.
• After an in-frame, injector change, or anything else that drains the high pressure oil system, leave the injector harness unplugged. Crank the engine until you get oil pressure, wait a minute, then crank twice more and connect the harness. This will get oil back into the rail, make fuel pressure, and the engine will start right up. Injectors can be damaged if they fire dry.
• Try a Lisle wrinkle-band piston ring compressor. I haven't found anything that works quite as well. It is very easy to use and inexpensive.           

Below is an assembly cheatsheet you can save as a jpeg and fill out for any engine. Better yet, Email me and I will send a copy in Word format. Then you can fill out the form and the headbolt torque pattern and delete the pattern's grid.

     

Inframe rebuild information cheatsheet you can copy and fill out for your own use.