Symptom One:
Funny thing. My wife drives the blue bomber, comes back 5 minutes later because forgot something. Back in truck and it won’t start…
What the heck? What did she do? She broke it!!
Symptom is that voltage drops to nothing when ignition is turned.
I fiddle and play around, determine that something is amiss with the glow plug relay. I buy a ford diesel glow relay and wire it up. Works great, problem solved…
See that grey plastic cylinder with the 4 bolts on top? That is the glow plug relay. Small amount of current goes from batter to glow button under dash. When button is pressed that small amount of current goes to the glow relay, causes it to open which causes a large amount of current to go from the battery to the glow plugs in the engine. Reason for this is you don’t want lots of current going through a little button…
Symptom Two:
And then about a month later a very similar symptom occurs, voltage drops to zero when you try to ‘glow’ or start the motor.
Now I’m spending hours with the multimeter, and searching the internets for advice. The best thread I can find on ih8mud is:
IH8Mud Thread On Problem Starting 3B
Previous owner was impetuous and seemed to have extra speaker wire. Lots of spare wires zip-tied together. Lots of unplugged things (mostly from auto-glow system.)
Truck developed problem after sitting undriven for a few weeks. For in-car readings I used a cigarette lighter volt meter. Symptoms were all over the map but primary problem was:
– turn key one click, inside voltage is 10.4, yet batteries show 12.5 volts.
– turn key another click, voltage drops to 6-7 or below, yet batteries show 12.5 volts. The inside voltmeter barely displays at such low voltage.
Other times (seemingly randomly over 2 hours of exploring.)
– turn key one click, 10.4 volts
– turn key another click it stays at 10.4… woo!
o Hit glow switch and voltage dives to zero. Battery voltage never changed.
o Hit brake pedal and voltage dives to zero.
o Try and crank and voltage dives to zero.
After diving to zero the truck is dead for 30 seconds or so, then voltage recovers. The entire time the battery voltage is stable at 12.5.
I measure voltage and resistance across many places in engine bay. All seems fine. 0.3 ohms from starter to battery, from starter solenoid to battery. Cleaned battery posts and all cable ends. No difference.
Used jumper cables to ground all sorts of stuff (starter, block, frame) back to the – battery terminal. Made no difference. Jumped right battery to my… other… bj60… inside voltage shows 12.4. Try to glow and voltage goes to 6-7. Try to start, it cranks! A few seconds. Almost starts. When I stop cranking the inside voltage goes to 6-7 again.
Hmm. If jumping sort of works? Took batteries in for load test, supremely uninformative test machine gave them ‘pass’ light when set to 700cca.
Figured based on this thread to just build new ground cables because the old ones were so ugly. Worst case I have nice new cables.
Nasty old cable end
More nasty cable end.
What a pair they make, more nasty old ground cables.
Built new ground cable from 0/1 cable I got from Napa ($7.5/foot), and some other 0/1 cable from Lowes (napa ran out). The napa stuff was flexible, lowes was THWN-2 and is much harder to bend. Expensive fittings were $2 each at Napa. I crimped the ends on using a big vice. For kicks I also replaced the ends on the hot wire from ‘+’ of right battery to alternator.
Cables replaced:
– left negative to left battery tray bolt
– left battery tray bolt to left engine block
– right negative to right battery tray bolt
– right battery tray bolt to right engine block
– ends on that alternator cable
Passenger side engine ground attachment.
New ground wire from driver side battery to body.
After bolting the cables on… success. Everything is perfect and back to normal.
Woo! 12.73 volts!
In all of this the only thing I found wrong: I noticed that the – battery terminal clamp for the right battery was quite loose. Resistance of old cables seems fine so must have been that slightly loose clamp on the right side? When playing with jumpers I only grounded to left battery (battery + are connected with cable but negative are each independently grounded to body and block.) In hindsight I’m guessing the truck would have started working if I’d just jumpered the left and right – terminals (because I believe the left ground was good.)
Advice for building your own ground cables: After building and installing the new cables I did some research. The cheap cable from lowes is made of fewer thick sold copper wires. It is too stiff and will not age well given the motion of the diesel motor relative to the body. Marine cable is zinc coated, is the most flexible and has the best temperature and chemical resistance, and 0/1 is sold locally for between $4.50 and $7/foot. If I ever do this again I’m using that stuff. Also I’m going to get some good copper battery terminals.
Building Cables:
Well, that success lasted all of a day before I realized I couldn’t live with that hard conduit cable in the truck. No way would it last, its too stiff and will break.
I head to west marine and buy 6 feet of their ANCOR 0/1 marine cable, in black. It is very flexible and has terrific fuel safe, self extinguishing insulation. Also it is tinned so corrosion resistant. I also head back to Napa for 4 more of them $2 fittings.
Lastly I go to amazon and look to see what is available in a cable crimper!
Looking at all the crimpers on amazon, and on the internet in general I realize that a simple “Hammer Crimp” is all I need. That’s what folks used for 80 years, what old service stations used forever and ever. It ought to be fine for me, and make a better fitting that what I could achieve by squishing the ends in a vice. Further benefit is that they are ~$25.
On amazon I look at all the crimpers, all look similar, can’t tell them apart. Luckily one of the crimpers is made by Temco! Temco is BAD-ASS company that builds large industrial transformers, inverters, BIG electrical stuff, stuff that architects take into account when designing buildings. Stuff that costs $50k to $500k. They make a range of crimpers from the simple hammer crimp up to $1k pneumatic/electric crimpers. These guys make crimpers because they know what they’re doing and need good crimps. Nice that they think of the little guy, take the trouble to build a cheap reliable crimper.
They even have a photo on their site of what a proper hammer crimp looks like. The crimp with hammer hits so hard that the copper strands are welded into a solid under the crimp. BAD-ASS!
Link to Temco Hammer Crimp on Amazon
I cut new lengths, put on the shrink wrap, crimp the ends on. Wow this stuff is flexible. Never thought much about ground cables before. These are sweet!
CanadianBJ 