I know a while back TooManyToys. was talking about coming up with some information on where to add grounds and which ones to upgrade. I installed a new Bosch Alternator in my truck thinking that is why I had lower voltages and sure enough I have the same voltages as my stock alternator. Im using an overdrive pulley too..

Im going to venture to say that I need to upgrade the grounds now. I did add a cable from the alternator post to the battery and it didnt help much. I do have the ground under the passenger door ( body to frame ) and I have the ground strap from the head to the firewall. Should I go larger on them? I can get HD insulated wire and I can glue heatshrink and crimp the connections. I have No-Ox grease too already....

Any help on this would be appreciated.

Thanks.

 

What are the voltage readings.....
at the battery posts......
not running?
running afterm 2 minutes at idle?

at the alternator post.....
not running?
running afterm 2 minutes at idle?

This info may help.

 

No! Do NOT upgrade those or add a big cable between the alternator and the body work.

First do the checks 87crewdually just mentioned.

Make sure the battery grounds at the frame, engine and the little ground off the pass batt are clean first. I'm still deep into other things before I get that other Vid done, which turned out to be work then I realized.

 

Also, with what are you measuring voltage?

 

Following along to see if I can learn something.

 

I will do those check but we're getting pounded by rain and will be until sunday it seems, but I will report back... Im using my Edge CTS via OBD2 to get the voltages. I know it can be lower but it seems, well lower than it should be. Im at around 13.5-.6. Maybe 13.8, but IVe seen other 6.0's at 14v +... Maybe certain years outputs more voltage to the OBD2 devices than other years? I did check at the posts once and it was 14.0x v... I do remember that. Does anyone have locations for the battery grounds? And I have a cable from the alternator positive post to the battery. I did that to help with the glow plug draw.. Should I NOT do that?

 

No, that cable is fine.

A. Where are you located at?

B. Do you have access to a voltmeter? Rather then the Edge.

I can pull up the wire / body contacts to clean.

 

Just south of yiu in MD. And yes I used a DMM on the battery. It's just I have a pid up on the edge and it's what I use since well, it's right there lol

 

I understand it's an easy read. But it can cause you to go crazy because of its lower values compared to what's happening with the primary voltage supply. That's why a voltmeter is so important because with it each connection under the hood can be checked for drops.

I had started to do a vid on checking voltage drops on our trucks a year ago but figured no one is ever going to watch this. Let me see if I retained them in my Sandisc storage as I have to clear my iPad/iPhone storage as that gets filled up often.

We both have till Sunday before it clears, but this morning I was informed we'll be visiting Wheaton Village on Sunday.

 

I don't see your concern. Once the batteries are back up to charge there's no reason to have a constant over charge.
My 2011 Yukon and 2014 Tahoe along with other 6.0's I work on behave the same. I really believe manufacturers design it that way so you're not cooking off the water in the battery. As long as the gauge shows 13+ it's working fine.
I wouldn't beat my head trying to get 14.6v for no good reason. That's my take on it and opinion.

 

Oops, just read post 6.

The alternators output may be in the 14.2-14.4 during the initial 5 minutes of start, but as the alternator heats up the regulators have a temperature compensation circuit to protect the batteries and will drop that to ideally 13.6-13.8v. The numbers you have are typical and not an issue as they are told. The OBD port readings will be typically lower then that, and that voltage will depend on how nuts you want to get. I'm nuts.

This is a section out of a vid I have on alternators. This is a Bosch 140a, small pulley. The voltmeter reads off the pass battery, so it's one of the highest voltages with minimal drop. The ammeter on the left reads only the glow plug amps, and the ammeter on the right reads the alternator output. The OE harness has been modified so I can do this. This is an initial startup on a winter morning, and the stopwatch is there fr reference. The OBD port will be lower then this.

You can read the meters better by going to YouTube and select 480 quality.

 

The vid is from a modest harness change and cleaning all the harness grounds and the PCM pins to ensure minimal voltage drop. Plus it has the L-N 230a, which shouldn't matter over the 140a with the small pulley. I'm showing not that you need to achieve this high of a voltage off the OBD, and in fact this is only on my own truck and I can't say it would translate to any other vehicle.

But the purpose is to show that during initial cold start voltage will be high, but once the underhood gets hot the regulator will drop the voltage output to protect the batteries. Heat and high voltage is detrimental to batteries, and the reason that E Vans have a lower warranty percentage for batteries then the F Series. The E Vans have the batteries off the frame rail and not underhood. And northern F Series have better warranty then southern F Series.

 

Yeah true... I'll check with the meter soon. And yeah you're getting hit too, Sunday should be a 50/50 nice day but I'll have to catch up on some home stuff too.. I have to run to the recycle center and drop off all this oil and coolant.

Ahh I don't want an over charge. I was chasing the 14v as I see many say oh you should be in at 14v all the time. Any less you're batteries, alt etc are weak... Damn internet. Lol.


Nice thanks. That's the same alternator I have , recommended by you. I had to reclock it.. remember? It wasnt hard at all.. just the casr was tight so it took some tapping and constant watching as to not let it drop too far out, then there goes the brushes.

Appreciate the information. Can you tell me where the grounds are attached to the body etc?

 

Also I see you have one of those voltmeter cigarette plugs. Are they as accurate as going off of the battery? I don't smoke so I can substitute the cigarette lighter for that and I can get a more accurate reading vs the odb port, again if they are accurate or more accurate than the odb

 

I'd also like to know wheee body meets ground. I just replaced my cab and I have this sneaking suspicion that I forgot one but I can't find it. I know there's a bare braided type one under the passenger seat to frame, and the one from battery to engine block but where else?