Volt problem helppppp about to set it on fire!

[gn_steve]

Hi guys and gals here is my problem my volts on my scan master are every where from 11.9 to 13.8 and when fan comes on never over 13.3 and when i am driving 12.4-13 volts my fuel pump is starving my car when i floor it cause its missing voltage!
When i am driving the voltage goes down to about 12.4-12.7 isn't it suposed to go up???
Here is what i did up to know

Changed alternator to a lt1 140 amp
Checked grounds all ok
Instaled 8 gauge ground from battery to fender
Checked all connections of scan master
Changed battery

Here is what it does at idle

What else am i missing do i buy a volt booster?? Will that solve the problem?
Please help ?????


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[NY_GN]

2 quick ideas;
-Hotwire kit for fuel pump
-Caspers alternator field fix

 

[gn_steve]

But what is causing this problem???


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[TurboTGuy]

Check the connections at the starter. Ensure nothing is grounding out when the motor torques.

If that isn't the problem, check all grounds again, including the one on the left wheel well in the trunk.

 

[gn_steve]

Check the connections at the starter. Ensure nothing is grounding out when the motor torques.

If that isn't the problem, check all grounds again, including the one on the left wheel well in the trunk.

The left wheel well where exacly does the ground plug from where to where???


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[DeltaBravo]

The left wheel well where exacly does the ground plug from where to where???


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^^^what he asked...

 

[Antbankstwo3]

I had a similar problem. It ended up being a bad connection from my speedo dash console to the connector behind it. I took the out & cleaned all the connections with clean tip eraser. Then I slightly & carefully bent back all the ends to unsure they touch & got a good connection before reassembling. I also went ahead & changed the volt bulb & cleaned around that area too since that completes the charging connection. My car has been good ever since. Im not sure if that all makes since, but maybe that will help.

 

[Chuck Leeper]

The left wheel well where exacly does the ground plug from where to where???


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From the rear harness, to the tab @ the floor, just below the tail lite mounts. It's a screw.

 

[TurboTGuy]

From the rear harness, to the tab @ the floor, just below the tail lite mounts. It's a screw.

^^^ what he said.

 

[salvageV6]

Put a volt meter on the alternator or battery, viewable while driving, forget the scammaster reading for now.

 

[pacecarta]

check output at the alternator bat post (test with ground of meter at battery neg post) and see if the voltage is jumping .. if its steady the problem is in the wiring to the dash
check the orange wire by battery positive terminal for weak or broken fusible link , check fusible link connections at starter terminal , bad ignition switch , bad grounds at back of head or at dash ..

if voltage is jumping around when tested at alternator .. retest with meter ground at motor clean metal spot on motor , then with ground at alternator case and see it improves ..if it does the neg bat cable at motor or case ground is poor ..if it doesnt improve ...
is the charging wire and terminal tight or wiggling around?
check the field wire .. L port brown wire to the volt bulb in the dash . to properly charge the volt bulb has to light with key on engine off unless you have the bulb socket with the resistor across the back
is the belt slipping ..the 5060640 isnt the correct belt
check it for a/c output .. bad alternator
check alternator case is grounded to the motor (painted brackets or powdercoat can caus e problems ). run a ground wire from the back of the alternator case and see if it improves
if it still jumps replace the alternator

 

[JimG]

Stefano,
I was concerned about my voltage being lower than it should and I replaced both the positive and negative leads from the battery, and that brought everything back to spec.
Thanks
Jim

 

[Chuck Leeper]

Problems like this are what voltage drop tests are for.....Do both the +&- sides.

 

[gn_steve]

Problems like this are what voltage drop tests are for.....Do both the +&- sides.

How do you do that??


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[Chuck Leeper]

How do you do that??


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Steve, here's just 1 of many vids, written explanations.