[T3] Fuel Pump Relay - 69 Fastback

Jim Adney jadney at vwtype3.org
Sat Jul 10 22:43:03 PDT 2021

On 10 Jul 2021 at 15:51, Tim Schiller wrote:

> Voltage at battery 11.84, voltage at power relay 11.84

Sounds pretty low.

> Turn key on and voltage at power relay drops to 11.67 Is this enough of a
> drop to make a difference?

Regardless of where it started, it's normal for the voltage to drop when you 
start drawing current.

> Voltage at fuel pump relay (87 pin to fuel pump)when cranking engine is 9
> to 9.8

Sounds very low.

If the battery voltage isn't above 13 V when charging, it's possible that this 
battery has a shorted cell, so you now have a 10 V battery instead of a 12 V 
battery. Almost any amount of charging should bring the resting voltage 
above 12 V if all 6 cells are working.  

If charging seems to be making a difference, do what you can to reduce the 
charging current to less than 1/2 A, then keep it up for a week and watch the 
voltage. It should rise somewhat steadily to nearly 14 V. Don't let it go above 
14.5 V.

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

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