Voltage fluctuates with rpm of motor.

L

Lamb

Member

Apr 22, 2002

31

0

6

Nov 19, 2006

#1

• Nov 19, 2006

• #1

Please help me figure this out. I have a 1990 saleen with an up graded alt; new battery. The violtage in my car fluctuates with the rpms as does the brightness of my headlights etc. This is a particularly annoying situation since my fuel pump is directly wired to the coil and it makes for a difficult time tuning the vehicle. If anyone knows an answer to this situation I would greatly appreciate some enlightenment.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

34

129

Nov 19, 2006

#2

• Nov 19, 2006

• #2

More info is needed. What flavor of upgraded alternator do you have? What is the differential in system voltage, etc.

At idle when the alt output sounds to be dipping, the demand on the FP is minimal, so 'performance' should not be seriously affected. Something along the lines of a component booster (B-A-P, etc) can help with the situation, if there is one.

Anyhow, more info please.

Good luck.

 

MikeC

Founding Member

Aug 1, 2002

240

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16

SLC, UT

Nov 20, 2006

#3

• Nov 20, 2006

• #3

Do you have underdrive pulleys?

 

tbovee

Member

May 22, 2006

129

0

17

Fredericksburg Va

Nov 20, 2006

#4

• Nov 20, 2006

• #4

I agree with everyone above. More info. But you could always check all of your grounds first,

 

sjhm9102

New Member

Jul 10, 2004

0

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0

texas

Nov 20, 2006

#5

• Nov 20, 2006

• #5

slipping belt or you need a new alternator

 

D

Daggar

New Member

Jul 19, 2004

3,902

5

0

Nov 20, 2006

#6

• Nov 20, 2006

• #6

Things that come to mind with available info so far:

Field wire connected to improper location
Bad regulator
Bad regulator diode (will usually manifest itself with a dead battery after sitting over night)