New record low voltage?

[Nick Micale]

Today a customer was by to check a few items on an original, un-molested GN with under 50k miles, as he was having a few issues.

His main complaint was at highway speeds, it bucked and lost power when accelerating, but ran fine around town.

Since this sounded like a fuel delivery problem to me, he said it probably had the original fuel pump. I wanted to first check voltage at the pump connector, as I did not want to take a chance of checking fuel pressure at WOT.

I feel this was a good call as the record-setting, low voltage at the connector was 8.4 volts, with battery voltage over 12 volts!

This example illustrates how wiring/connector issues in a 25 year-old car can deteriorate to such a bad state.

 

[87chrisss]

I think i top that, just last night i had to run a home made hotwire my fuel pump plug was showing 7.90- 8 volts @ stock wire harness plug not even at pump. So pump might have been seeing close to nothing..

 

[bison]

I recall low 9's but never 8's on a running car. I've seen 0v with a crank but no start that was caused by other issues.

 

[87chrisss]

i ran 7;6 with stock FP harness... im thinking the volt booster is what has been helpin me out!

 

[dynoman]

Nick did you drop the tank and check the rest of the wiring because at 8.3 vdc he had to be drawing high current all the time !!