Chasing a low voltage issue. Before I drop $ on new powermaster need opinion

[Toby_Goodmk]

I have a condition that unless the car is at idle or at highway cruise speed with little to no load I have voltage drops as low as 11.8

I have performed the following

Load test on battery = good
Grounds are good, battery ground on head and good
New Caspers complete wiring harness as well as positive batt cable and upgraded alt cable
Ground at pass fender from battery is cleaned and good.
Cable at starter is tight.
Cable at alternator is tight
Ground strap from engine to firewall good
Grounds from caspers engine harness to engine good
Bulb test on back side of speedometer cluster is good, continuity from either side of the circuit board is good

So I have a new alternator (6 months use) that I feel may be taking a dump. Before I spend the money to get a "quality" alternator and stop messing around I wanted to get opinions. As soon as the car has a load it drops from 13.9-14.0 to 11-12v.

Thoughts?

 

[GBGN1]

Try throwing a new regulator in the alt. Cheap and cannt hurt.

 

[Toby_Goodmk]

Try throwing a new regulator in the alt. Cheap and cannt hurt.

I have a full warranty so ill try changing it out first.

 

[Toby_Goodmk]

replaced under warranty the alt....same issue. Frustrating sob

 

[DR BOOST]

measure voltage from the back of the alternator. I had a problem on my car that i would have 14 at the alternator and 11.2 inside the car. After a few hours of chasing wires, i found my ignition switch to be faulty.

 

[Toby_Goodmk]

12 volt

 

[Toby_Goodmk]

So I have gone so far as to looking into the main cluster harness. Found the brown wire that excites the alt...checked continuity...all good there. So I took two jumper wires. Put a jumper on the same brown wire in the cluster harness. Took a jumper and hooked to the white wire on the harness directly across from the brown wire. Common sense tells me if I take and put a known good bulb between these two I should excite the alt....nope...it doesnt. So does my hypothesis make a correct assumption that I have an open in the white wire? And does anyone else know where the wire wire leads to?

 

[Toby_Goodmk]

Still going at it. I will need to get a new flex board as I bypassed the bulb in the car to a bulb right off the alternator straight to 12v at the battery...its charging. So I have the board to upgrade first, then if that doesnt do it, it must be an open in a wire somewhere.

 

[Chuck Leeper]

measure voltage from the back of the alternator. I had a problem on my car that i would have 14 at the alternator and 11.2 inside the car. After a few hours of chasing wires, i found my ignition switch to be faulty.

AIRC, there's thread on how to use a relay to handle the hi loads, and bypass the key sw....

 

[Toby_Goodmk]

Decided to make my way to the Shack and get some 1k ohm resistors. Made a connector, split from it into the brown exciter wire. Done.... Amazing...voltage now, no KR. Amazing what happens when you starve something in the system. I knew something is not right, now it runs like hell again. I will be installing a voltage booster however.

 

[John Larkin]

Pic please? Good job.

 

[Chuck Leeper]

What John said....

 

[Toby_Goodmk]

Guys I wish I took pics. It's very simple. Just a simple resistor from radioshack. 18" long wire in line. Tap ANY 12v switch and splice brown wire. That simple. I already hid the wire into the harness or I'd take some. When I take all the wide band out and do some re wiring when the fast comes in I'll take some of the setup