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I suppose it is possible that both your green and black connectors are shorted out such that every glow plug circuit is shorted out at that connector. Hard for me to imagine, but I am sure stranger things have happened.
With what you have posted, I'd be taking one of those connectors apart (remove the face plate) to look inside at the actual wire, assuming you haven't already done so. If it all looked good (no burnt wires), I would then repeat the resistance testing - you have better access to the contacts/wires.
yes ive done that already, everything looked good,, i did see another test with the GPCM pluged in and a guy used a paperclip in the back of each plug to see if power was being sent to that cylinder,, should be 10.5 volts or so,, but i cant get a pin in on the back of mine and dont want to open any wires up to check,, so yep still stumped, i have done alot of research on it and it may look like i need to remove glow plugs and test each, remove harness and test, and find a way to test the GPCM , with the battery voltage problem i have, a freind did look it up and apparently 12.3 is normal, which is odd since the numbers dont match with what a charging system should do, much like coolant level being normal at 1/2 inch below full line
If the glow plugs were shorted (0ohms) wouldn’t the harness be smoking after a few seconds of power applied? It’s been my experience they fail open (no continuity).
one would think so yes, but i have no smoke,, lol thats a good thing,, i wanna tes my meters i think and see why im not getting a ohm reading,, it could be the meter its self, now to find something to test it on
12.3V after the glow plugs have turned off is not normal if the alternator is working, it is good for when the glow plugs are on.....unless you have a 300+ amp alternator. And IMO, paper clips have no place in an electrical testing process.
That write-up on powerstrokehub states that the even cylinder glow plug circuits are on the green connector and the odd ones are on the black. I guess you noticed that DieselTechRon presented it the opposite way ....... wonder which one you will follow ................... (edit, for "facts", - the Work Shop Manual agrees with DieselTechRon, and not what you posted!).
If I could just throw this in. My truck lives in the South and has a pretty easy life, seldom below freezing, but I have cranked it a few times not plugged in, in single digit temps (f) in Ohio. Commonly, a 30 second crank sounds like it want to start and smokes some. A couple minutes rest and a second crank, maybe a little longer than the first, more smoke, it finally runs on its own. A minute or two and the shaking settles down and when the temps start to rise it’s good for the rest of the day. Point is, frozen oil and batteries and it cranks for more than a minute total without slowing down. If you only get 20sec or less in “warmer” temps before the battery is flat I would think there is a problem with batteries/cable/starter. Battery problem could be charging system of course but it would take a huge draw from the glow plugs to kill the batteries that quick. I’m not saying the GP’s are ok but something else is going on.
wow,, a 30 second crank would leave me with dead batteries,, im in canada,, alberta,, its above zero here, celcius, been hitting 20 a few days, but i have noticed starting is easier as it is warming up, which leads me to glow plugs, but does not solve my battery charge issue,, yes something is going on, especially when hardware passes the tests
Right or wrong, if something is found to be wrong with the glow plug system (which 0 resistance is an issue if that is an accurate test), then I would address it and then move on to the other issues (whatever they may be). That assumes that the suggestions in post #2 were already completed (which includes inspection of battery cables and connections, AND starter cable connections). Bad grounds (especially the block ground) could easily cause issues with battery charging, but again - that was suggested already. No indication of being done yet though!
Several other possibilities fairly easily investigated:
1. Belt-driven accessory "freezing up" causing issues with reduced alternator output due to low rpm.
2. Starter or starter wiring issues (one engine I recall had a starter wire short to a block drain fumoto valve). I wonder how hot the starter is getting ......
Only as an fyi, a GPCM (control module) issue can have a significant electrical draw - but that usually shows up fairly quickly as heat.
You should have more battery reserve than what your situation indicates. If you had the batteries load tested, how about showing what the CCA capability they have is and the CCA rating of the batteries. You might have the normal capacity, but it gets drained down. Battery voltage at the time of the overnight shutdown and then again before the key goes in might show some indications.
Something is wrong with your ohm readings, and you need to study up on how this glow plug system works rather than barking at Mark.
This would be a normal voltage response from key-on through the glow plug cycle. Showing both the stock 110a alternator (most like have) and the optional 140a.
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