 Voltometer Question, experiment only shows 8 volts, why? |
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| DougC |
 Jan 11 2006, 10:34 AM
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#1
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Senior Member  Group: Members Posts: 949 Joined: 6-July 04 From: Dallas, TX Member No.: 2,307  |
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 |
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| SLITS |
Jan 11 2006, 10:52 AM
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#2
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None  |
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.
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| 914GT |
Jan 11 2006, 10:52 AM
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#3
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Senior Member Group: Members Posts: 1,100 Joined: 11-October 04 From: Tucson Member No.: 2,923 Region Association: Southwest Region |
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.
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| ClayPerrine |
Jan 11 2006, 11:27 AM
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#4
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Life's been good to me so far..... Group: Admin Posts: 15,450 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille 
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Bring it with you on Sat and we will compare it with my DVOM.
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| DougC |
Jan 11 2006, 11:28 AM
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#5
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Senior Member Group: Members Posts: 949 Joined: 6-July 04 From: Dallas, TX Member No.: 2,307 |
Thanks for the advice guys, I will try both..
Doug C |
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| bd1308 |
Jan 11 2006, 11:49 AM
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#6
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Sir Post-a-lot Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501 |
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 |
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| DougC |
Jan 11 2006, 11:52 AM
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#7
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Senior Member Group: Members Posts: 949 Joined: 6-July 04 From: Dallas, TX Member No.: 2,307 |
Will Do Clay.. and thanks for the confirmation Bd1308.
Doug C |
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| ClayPerrine |
Jan 11 2006, 12:54 PM
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#8
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Life's been good to me so far..... Group: Admin Posts: 15,450 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille
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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. |
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| bd1308 |
Jan 11 2006, 01:09 PM
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#9
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Sir Post-a-lot Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501 |
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 |
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