Jack: the one video has a caption "Large pulley" and then the next "factory pulley". Did you actually try going to an under-drive pulley while you were testing this Voltage cycling? I had mused on this before, whether that might help the GPCM start-up issue (albeit lessening the output of the LN everywhere...).

Scott

 

Good videos again Jack. The first video is exactly what my truck does when air temperature is around or below 35F and cold soaked.

 

Large pulley, factory pulley, stock pulley are all the same, just my lax naming of the same pulley.

I'm playing with my motor but I'll take a minute for how I see things.

Vid 1, small pulley OD, stock wiring, warm temp. The typical tug of war between the alt and GPCM. Amps early on when GP and Batts suck maximum amps are up to 190-200 with this faster spinning setup.

Vid 2 same setup, older recording before understanding this. Same setup, older batts, colder temp. Due to the lower capacity older batts the volts just kicked up and stayed up. Life was good.



Vid 3 Stock pulley. The amps have a slower rise and are limited at this rpm to around 180-185. It takes longer to get to the voltage threshold but it's less reactive once it's there. Can still be, it will depends on Batts resistance/need to refill and starting draw down.

Vid 4a smaller OD pulley, alt to power junction connection at the drivers batt for less voltage drop across all the cabling. GPCM just kicks out to the higher voltage.

Vid 4b stock pulley with above noted cabling. Back to funky again, but a little less reactive. With the stock cabling the system voltage is tenths lower, but with less voltage drop of the additional cable, back to square one.

Vid 5a "It's your sense wire in the harness". Factory pulley, changing to sensing voltage directly off the drivers battery post, the voltage is even higher, 14.68-14.80. Good direction if you want to keep the GPCM off, not the best for AGM batteries. But it shows that the bolted connections voltage drop have an influence on the harness system voltage, the alternator is trying to push through the connections with higher voltage since it's sensing later in the system. Well at least in my weird world explanation.

Vid 5b Just a stock confirmation after the alternation.


Vid 6a "It must be your sense wire connection II". Going director alternator output (some applications do that), stock, large pulley. Same tug of war.

Vid 6b back to stock again for confirmation. The "tests" were done in the am, the confirmations done in the evening on the same same so I could let the motor cool back down and the batteries to settle down.

Laurel-Anne, one thing your will notice in all of these is the battery voltage never drops into the 9's, maybe a little with the old batteries, which is why they were changed, getting too low in the 10's. You don't have it but during these I have a starter that about 75% of a 6.4/6.7 starter, so my starting draw will be deeper then yours, and I'm still in the 10's. 15F butt cold would have been worse though.


With all of this, at the end of the day if the voltage regulator would stay 14.2v none of this would be happening.

 

I don't think I mentioned on this thread that in the screenshot I posted, the low in battery volts dipped into the 9's. It was 11.125 KOEO, then down to 9.062 . Was back up to 10.5 after 1.6 seconds, but still- that's low. Once the GP were off, the average reading was 14.18. I'll be testing capacity soon. These batteries were installed 20 months ago, but we haven't been particularly careful with them.
One of my tasks today is trying to find out if any of the parts places in town will test them for free, otherwise I'll be shopping for a tester.

 

Laurel-Anne (corrected above),

This is the one Randy showed me, he said it works well. I got the one above it in price although I never use those extra capabilities, but at the time it was closer in price.

 

O.K., so this morning @ 4?°f I turned on the key and of course had glowplug light. I realized my defroster was on so I turned it OFF. Glowplug light went out, started the truck, and it went up to 14.2 and never dropped. Even though I could hear and feel the load coming on every time the GPCM powered up the glowplugs, the voltage stayed solid 14.2v. In the morning I'll see if I can duplicate it.

 

Pete, at the alternator or off the monitor? All my reads are off the alternator or battery post. I was trying to not take a system reduced voltage.

 

(File picture above) Readings from this while plugged into the PowerPoint which is as close to battery voltage I've seen since the ScangaugeII as you know reads .5 volt or so lower. I can go right to battery or alternator if you want but last I remember this was pretty close if not the same.

 

My dash is closer then the SG2, but it’s still lower then off the alternator or pass batt. Somewhere ..... a have a ground or connector I need to clean. Also the two ports on my dash are a little different.

But in the course of trying to get this data to L-N I just wanted to get any questionable data path out of the equation, aka it’s your powerport.

 

I have a couple of follow ups - I emailed both ficmrepair and Prestolite, and Ed emailed back right away. He says they've been receiving more reports of this issue in the last month or so, and that they are waiting to hear from with L-N engineers.
And I got nothing from Prestolite.

And as for my batteries, I stopped by NAPA and they read 12.8 and 12.76

 

Voltage doesn’t matter, capacity does.

 

I had a feeling that wasn't all I needed to know. He said "they pass", and there were other readings on the screen, but I didn't catch what they were.

 

They may have checked the capacity then, but it is the important condition to keep track of. And it’s always good to have the value for the people who are active with the trucks.

 

Finally got a video of the fluctuations I have been seeing.

 

My question is,what does it say directly at the battery terminal with a good meter. You will know the real deal then. I get the same thing on my Torque pro in the Ex,but the meter at the batteries is steady