Tech Note: Buried...

It were the bitch bolt from the fornicating front gates of hell it was. Buried beneath everything, barely visible, about the last thing I pulled loose when I pulled the engine out to overhaul it, the first thing to go back when the engine was back on the mounts.  And of course pursuant to Murphy's law, chapter five, section thirteen, that was the one bolt that had to come loose.  Go figure.  I had the victory though,  at the cost of multiple minor wounds to me knuckles and a new set of fancy flex head ratcheting box end wrenches and eight hours of most deliberate patience it did, finally, come off.  Nike!

Why the effort?   Me pickup truck has been being a royal pain in the ass for a couple of years, refusing to run reliably if he'd run at all.  At first I just wrote it off as twenty years of wear, I'd overhauled the hardware but not the electrical side of things, I figured it was just old age taking it's toll on the components.  But when I'd run out of parts to swap and the problem persisted it became more than a bit of a mystery: what in the hell is causing the problem?  

I eventually decided at least one of the components I'd changed had to have been defective out of the box, so back down to O'Riellys I went (I will plug their business, they've been GREAT about the whole affair) to check on warranties. Counterman pulled up the history, and as I'd thought, I'd bought lifetime warranties on all the critical pieces.  He said "ah, hell, just pull the whole damn system off and bring it down, we'll test what we can, trade what we can't."  You can't ask for better than that.  That statement caught the attention of another guy who worked there, he drifted over to find out what was going on.  Fifteen seconds later, brought up to speed on the situation, he volunteered the critical piece of information. 

Seems he'd worked with similar systems used in the boating industry, the big speedboats that often run large automotive style engines adapted for marine use.  He  asked me if I’d checked the resistance on the main ground cable between the battery and the engine.  That’s a huge wire, cable really, if the terminal ends are clean you normally don’t have to worry about them.  Normally they don’t have any resistance to check. But he said they’d worked on more than a few however where they’d found the copper wire in the middle of such a cable all but burned through with corrosion beneath perfect insulation.  Said they’d still spin the starter just fine, but would drive sensor grids and computers insane to the point of self destructing with the microvolt differential in the ground planes between engine block and chassis.  Now that was something I'd never seen before (learn something  new every day), but what the hell.  Nothing else had worked.  Back to the shade tree to clip one end of the volt-ohm meter to the negative post of the battery, one to the block.  Zero ohms, as expected.  But then, a flicker… .01 ohms.  Back to zero.  Wait a minute.  The little VOM is only throwing nine volts, not twelve, no appreciable amperage, and it saw a flicker?  What gives here?

Okadedokity Brutus (that’s the trucks name), you need a ground?  One end of the jumper cable to the block, one to the battery terminal, hit the key.  He started, didn’t sound happy, but started.  I idled him up to full temp, shut him off and waited thirty minutes to full heat soak, and checked again. Half an ohm give or take, and floating. Damn.  THAT… is not supposed to happen, which is what precipitated the battle with the bitch bolt, the one that holds the ground cable to the block at the very bottom of the pile of things bolted to the front of the engine.

Long story short?  Having changed the cable I put the original cable that Ford put on there twenty some years ago on the bench, cut the perfectly intact insulation off it, and lo!  About two foot up a forty inch cable the corrosion was so bad  it dumped a pile of powder on the bench!  There it is,  bigger than Dallas and ugly as homemade sin, that’s been the problem all along, and I was the one bolted it back on back in the day deceived by the insulation.  Double damn and drat.

So, the point of this story?  A new rule to sit beside the First Rule of Warehouse (See the floor?  Sweep the floor, you never know how long it might be before you see it again)... those damn cables are part of the system, they’re cheap, so change them anytime you’re dug down deep enough to make it convenient!  A fifteen dollar cable is cheap insurance compared to five hundred some dollars worth of electronics and a whole bunch of headache.  

Oh, and if some grizzled veteran starts out his story with “you know, back when I worked at … ()… we used to see…” it’s wise to listen to him and check it out, he might just know exactly what he’s talking about.  All I can say is Kudos dude, you called it blind.