# Strange Electrical Issue After Installing High Output Alternator and Dual Battery



## The Snow Punishers (Sep 30, 2018)

So first I'll say I had my dad help me who's a great electrician but not the best mechanic. So I'm confident it is wired correctly especially since I'm getting 12.5v on each battery with the car off and little or no voltage drop with car on the 2 batteries and Alternator are running at around 14.2v but it is an erratic reading unlike with car off.
I have a 2001 Silverado 2500hd 6.0 with 130k miles and it hasn't even seen snow yet!
Basically ever since I installed the setup, only when idling (which seems low to me @ 550rpm) the "interior" lights not headlights flicker or pulse I should say. The voltmeter on the dash is erratic as well where it used to be steady. If the rpm climbs to even 650 with gas there's no problem. Only idling.

Now I've read that it's possible during installs the intake tube can dislodge a bit from throttle body causing low rpm. I will be checking this now.
I reached out to the alternator company nations starter and alternator who I found make high quality products last year and rebought this year and they say it may be the instrument cluster which has been going in and out prior to the install but would that make my dome light pulse?

Also, all wiring has been upgraded appropriately.

I also had to get a different size belt (it's not slipping like squealing but if you listen carefully does make slight squeaks but ever so slightly almost inaudible) because the pulley was sized for the 130amp alternator option and it had the stock 105amp prior.

So I got the continental brand not oem and am also wondering if that matters because the specs do have a .1" difference. That could mean everything for all I know.

Please post any info relevant I greatly appreciate it


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## The Snow Punishers (Sep 30, 2018)

I've also read a dirty throttle body can cause low rpm so I'm wondering if spraying seafoam in there would help


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## lefuchs'd (Oct 22, 2018)

Try checking the fuse for interior lights for corrosion. I had mine do that, and I pulled it, cleaned it, and it stop. I had not replaced an alternator, but it was getting low light in the truck at idle.
I am not sure if interior is connected to any type of relay, but might want to check there too.
B


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## The Snow Punishers (Sep 30, 2018)

lefuchs'd said:


> Try checking the fuse for interior lights for corrosion. I had mine do that, and I pulled it, cleaned it, and it stop. I had not replaced an alternator, but it was getting low light in the truck at idle.
> I am not sure if interior is connected to any type of relay, but might want to check there too.
> B


I will do that I bought some seafoam spray too clean throttle body


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## leolkfrm (Mar 11, 2010)

look at the idler pulleys and tensioner, might be seizing up and drawing the idle down


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## The Snow Punishers (Sep 30, 2018)

leolkfrm said:


> look at the idler pulleys and tensioner, might be seizing up and drawing the idle down


Do you think the .1" shorter belt could be adding to that too?


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## leolkfrm (Mar 11, 2010)

is it 1 inch or 1 tenth of an inch, one inch could if idlers are seizing


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## The Snow Punishers (Sep 30, 2018)

leolkfrm said:


> is it 1 inch or 1 tenth of an inch, one inch could if idlers are seizing


One tenth of an inch


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## Mebes (Feb 7, 2004)

The drop in RPM's may be a result of the increased load added by the high output alternator.
Fully warm up the engine then shut it down and pop the belt off and start it back up and see if your RPM's are a back to normal.
(Should be safe to run for a minute or so but don't run it too long without the belt)

Your fuel injection system should compensate for this added load automatically by increasing the air flow and fuel, but maybe there is some carbon blocking the passage or maybe the control itself is acting up.
Google "idle air control" for your make model and engine to see if this is a common issue


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## Cowboybill (Nov 14, 2018)

Can someone help with a celinoid problem,power to celinoid no power to pump


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## Cowboybill (Nov 14, 2018)

Cowboybill said:


> Can someone help with a celinoid problem,power to celinoid no power to pump


This stared after changing battery in jeep, I can by pass and run power to the switches directly and pump works but blade seems to be going back to left...im stumped


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## leolkfrm (Mar 11, 2010)

when i changed from 105 to 130 all i did was add a heavier charge line and some more grounds


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## leolkfrm (Mar 11, 2010)

Cowboybill said:


> Can someone help with a celinoid problem,power to celinoid no power to pump


start your own thread, this one is for alt issue and you may not get answers because of title


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## The Snow Punishers (Sep 30, 2018)

leolkfrm said:


> when i changed from 105 to 130 all i did was add a heavier charge line and some more grounds


Yea it was a different size pulley on 03 silverado 130 amp than 2001 105


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## Sawboy (Dec 18, 2005)

My truck was doing that same thing. 07 F350. Replace the Alternator. It’s defective.


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## The Snow Punishers (Sep 30, 2018)

Sawboy said:


> My truck was doing that same thing. 07 F350. Replace the Alternator. It's defective.


I just found out what the problem is... 
So it was idling low and I drove it a bit and it sat overnight went to do more diagnostics this morning and boom started up at 750rpm problem gone... apparently I read on some Silverados the idle speed needs to be relearned after resetting battery thank god


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## Mitragorz (Oct 11, 2013)

Relearned.

Computers...


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## Randall Ave (Oct 29, 2014)

The Snow Punishers said:


> I just found out what the problem is...
> So it was idling low and I drove it a bit and it sat overnight went to do more diagnostics this morning and boom started up at 750rpm problem gone... apparently I read on some Silverados the idle speed needs to be relearned after resetting battery thank god


Yup, If I have to disconnect batteries, if possible I set up a power source to keep the keep alive memory current.


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> Yup, If I have to disconnect batteries, if possible I set up a power source to keep the keep alive memory current.


Turns out it only works when cold then the problem happens again at 500rpm when warm any thoughts


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## Randall Ave (Oct 29, 2014)

Remove the belt and see what the idle is.


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> Remove the belt and see what the idle is.


Really? That actually sounds like a great idea thanks man! So if I understand correctly, with the belt off I can prove if the belt is too tight if I gain rpm on idle?


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## Randall Ave (Oct 29, 2014)

I re read this, Mebes had said this already, did you try it. And did you connect a good scanner and run codes and tests?


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## The Snow Punishers (Sep 30, 2018)

Mebes said:


> The drop in RPM's may be a result of the increased load added by the high output alternator.
> Fully warm up the engine then shut it down and pop the belt off and start it back up and see if your RPM's are a back to normal.
> (Should be safe to run for a minute or so but don't run it too long without the belt)
> 
> ...


Thank you I just saw this I will try this tomorrow


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> I re read this, Mebes had said this already, did you try it. And did you connect a good scanner and run codes and tests?


Sorry still getting used to site and notifications didnt see this


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## The Snow Punishers (Sep 30, 2018)

Ok so I finally got the belt off but i don't think i timed it right or did something wrong. I got an erratic reading.... unfortunately due to need of it being fixed I'm taking it to my mechanic Monday was the soonest I am gonna try a few things before then but I tried cleaning the Idle Air Control but the second bolt was pretty hard to get to with the alternator I have there... I really appreciate the help guys. I'm trying to be a long term member of the community and learn a lot and hopefully help others when I can


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## Randall Ave (Oct 29, 2014)

Just something to think about, I had a 98 with a 305, idled and stumbled like crazy. Dirty mass air flow sensor. Carefully cleaned it, ran great, like a different truck.


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> Just something to think about, I had a 98 with a 305, idled and stumbled like crazy. Dirty mass air flow sensor. Carefully cleaned it, ran great, like a different truck.


Funny you should say that that is my next task I bought the special MA Sensor cleaner yesterday I'll let you know how it goes


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> Just something to think about, I had a 98 with a 305, idled and stumbled like crazy. Dirty mass air flow sensor. Carefully cleaned it, ran great, like a different truck.


Were there any tricks to cleaning it it seems pretty straightforward


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## The Snow Punishers (Sep 30, 2018)

Ok I cleaned the MAF Sensor and it seems like it gained 500 rpm which helped a little when warm it's now like 600rpm cold idle is now 950rpm. I'm thinking this weekend I gotta get that throttle body off and clean that.


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## The Snow Punishers (Sep 30, 2018)

Randall Ave said:


> I re read this, Mebes had said this already, did you try it. And did you connect a good scanner and run codes and tests?


It threw a knock sensor code a few weeks ago but it went off on it's own. Also had misfire last month plugs should be relatively new


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## w3stern [email protected] (Oct 21, 2018)

Never a bad idea to upgrade the "big 3" either.


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## TJS (Oct 22, 2003)

The Snow Punishers said:


> It threw a knock sensor code a few weeks ago but it went off on it's own. Also had misfire last month plugs should be relatively new


Misfire is not just the plugs. The coil packs and coil wires can also do this. There are couple grounds on the coil pack harness make sure they are good. Also the pink wires firing the coils have been known to rub/chafe on the coil brackets. Make sure all is good. Find someone with a good snap on scanner and it will help you figure this all out. Also, check your exhaust manifold bolts for heads that broke off. Usually the ones way in the back. This can cause slight exh leak and create issues. If you have a mass air code replace the mass air meter, cleaning it is not going to do squat. I just went through this with my Wife's 6.0 escalade. MAF code and it was running rough. Replaced it and all fixed.


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