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914World.com _ 914World Garage _ Voltometer Question

Posted by: DougC Jan 11 2006, 10:34 AM

Hey guys I have a VDO voltometer that i will be installing in my 914.. well, last night I thought I'd make sure it worked before installing it and it would only show 8 volts. The "experiment" was that I just held the thing in my hand and attached a wire from the + side to the + side of my (new-ish) Optima battery, and a wire from the - on the voltometer to the - on my battery. The needle would just bearly bounce off it's resting place to about 8 volts. Did I test it right? Could my car actually be getting me around day-in/day-out on only 8 volts? The Optima is basically new, only had it for a few months but hit the starter a whole bunch trying to get my car to start when I installed my engine. Been driving the car daily for about 2 weeks now.

Doug C

Posted by: SLITS Jan 11 2006, 10:52 AM

Charged battery should show 12 VDC approximate....try your guage with a battery charger....If it still shows 8VDC, the guage is in error....if it shows 12 -14 VDC, the Optima is less than optimum.

Posted by: 914GT Jan 11 2006, 10:52 AM

Your battery is probably OK and about 12V (measured with engine, lights, etc. off) if it's been starting the past 2 weeks. If the engine cranks for a long time and doesn't start that's usually a fuel or ignition problem. Chances are the voltmeter is out of calibration or defective. The only way to really check it is to get a digital voltmeter and compare its reading at the same measurement points to your VDO meter.

Posted by: ClayPerrine Jan 11 2006, 11:27 AM

Bring it with you on Sat and we will compare it with my DVOM.

Posted by: DougC Jan 11 2006, 11:28 AM

Thanks for the advice guys, I will try both..

Doug C

Posted by: bd1308 Jan 11 2006, 11:49 AM

if you're getting around town, it is NOT at 8 volts.

trust me, you cant do anythign with 8 volts....even the FI cuts out at around 10...

BTDT.

b

Posted by: DougC Jan 11 2006, 11:52 AM

Will Do Clay.. and thanks for the confirmation Bd1308.

Doug C

Posted by: ClayPerrine Jan 11 2006, 12:54 PM

QUOTE (bd1308 @ Jan 11 2006, 11:49 AM)
if you're getting around town, it is NOT at 8 volts.

trust me, you cant do anythign with 8 volts....even the FI cuts out at around 10...

BTDT.

b

HIs is CIS on a six. If there is enough voltage to run the fuel pump and the igniton, it will keep running.

But I do agree, 8 volts willl not be enough to run the fuel pump, it couldn't maintain the correct fuel pressure.

Posted by: bd1308 Jan 11 2006, 01:09 PM

well clay arguably the coil wouldnt recieve enough input voltage so the strength of the spark would be pitiful as well...

the whole CIS/carbs deal is yet another thing, an afterthought on my part.

and arguably the low-power facet pump could probably run with a lower voltage but still 8 would be pushing it...

b