Voltage Issue?
06-08-2010, 11:17 PM
#1
Voltage Issue? Not really sure what section this belongs in so if it needs to be moved please move. To begin my battery is in the back using taylor battery cable and I even ran my ground using welding cable from the battery all the way up to the motor. With the car on I'm seeing ~14 volts at the battery and the same at the post on the fuse boxes in the engine bay. However, my stock voltmeter and my Aeroforce gauge are showing right around 13 volts.
The reason I'm posting this is because I was having a starting issue where I would try to start the car and I could just hear the starter click. I would have to try several times before it would eventually turn on. In the past few days I have installed a new starter and a new battery. This has made this issue almost non existent but it still does the clicking noise maybe 2 out of 10 starts. Earlier I was checking some stuff out and with the old battery I was seeing ~14 on both gauges while the car was on. I would then turn the car off and back on with no issues. Now that is has gone down to about 13 while the car is running when I turn the car off and back on I might hear the clicking.
What should the stock system be charging at and why am I not seeing the same amount of volts at the gauges that I'm seeing at the battery and the fuse boxes? It seems like I'm losing some voltage by the time it makes it to the cluster. With my key forward my voltage is anywhere from 11.5-11.7 volts. When it's in that range that seems to be when the car won't start on the first try. As mentioned earlier when the gauges where in the 14 volt range when I would turn the car off and the turn the key forward I was right around 12 volts and had no problem starting the car.
I don't know what changed from the time it was reading 14 volts to it dropping to 13 while running. My old battery up until a few hours ago was red top Optima that had been drained once so I figured it was time to get a new battery. I bought a humongous Sears Diehard Platinum battery with like 930 CC Amps but even after hooking up the new battery it still did it a couple of times.
This issue is starting to get frustrating especially when earlier in the morning I moved my battery ground up to the motor which is when I started seeing the increase in voltage and all of a sudden it dropped later in the day without changing anything.
The motor is grounded to the stock location in the frame rail using a 2 gauge cable. In the back the battery is grounded with a bolt and nut passing through one of the holes where the metal bumper used to bolt to also with 2 gauge cable. In addition to that I'm running a welding cable which I believe is 0 gauge which runs from the battery all the way up to one of the starter bolts. So the battery is grounded twice and the motor is grounded once.
I guess I'm trying to figure out what wire may be feeding power to the gauges and interior fuse box. Maybe I can trace that around to see why I have 13 volts in one spot and 14 in another.
Any help is greatly appreciated.
Carlos
The reason I'm posting this is because I was having a starting issue where I would try to start the car and I could just hear the starter click. I would have to try several times before it would eventually turn on. In the past few days I have installed a new starter and a new battery. This has made this issue almost non existent but it still does the clicking noise maybe 2 out of 10 starts. Earlier I was checking some stuff out and with the old battery I was seeing ~14 on both gauges while the car was on. I would then turn the car off and back on with no issues. Now that is has gone down to about 13 while the car is running when I turn the car off and back on I might hear the clicking.
What should the stock system be charging at and why am I not seeing the same amount of volts at the gauges that I'm seeing at the battery and the fuse boxes? It seems like I'm losing some voltage by the time it makes it to the cluster. With my key forward my voltage is anywhere from 11.5-11.7 volts. When it's in that range that seems to be when the car won't start on the first try. As mentioned earlier when the gauges where in the 14 volt range when I would turn the car off and the turn the key forward I was right around 12 volts and had no problem starting the car.
I don't know what changed from the time it was reading 14 volts to it dropping to 13 while running. My old battery up until a few hours ago was red top Optima that had been drained once so I figured it was time to get a new battery. I bought a humongous Sears Diehard Platinum battery with like 930 CC Amps but even after hooking up the new battery it still did it a couple of times.
This issue is starting to get frustrating especially when earlier in the morning I moved my battery ground up to the motor which is when I started seeing the increase in voltage and all of a sudden it dropped later in the day without changing anything.
The motor is grounded to the stock location in the frame rail using a 2 gauge cable. In the back the battery is grounded with a bolt and nut passing through one of the holes where the metal bumper used to bolt to also with 2 gauge cable. In addition to that I'm running a welding cable which I believe is 0 gauge which runs from the battery all the way up to one of the starter bolts. So the battery is grounded twice and the motor is grounded once.
I guess I'm trying to figure out what wire may be feeding power to the gauges and interior fuse box. Maybe I can trace that around to see why I have 13 volts in one spot and 14 in another.
Any help is greatly appreciated.
Carlos
06-09-2010, 07:26 AM
#2
A voltage drop through the ignition switch wiring can cause the problem you are talking about. Try jumpering a wire straight from the battery to the S terminal on the solenoid. Either that or wedge a screw driver across the battery lug and the solenoid S terminal. If that causes it to start every time then search the web for write ups on installing a remote Ford start relay. Pretty easy to do.
As for the gauges reading different, hook a multimeter across the gauge terminals and see if they agree. Maybe the gauge is just off. If it isn’t, then you probably have some current draw through the harness that is causing the drop. Just start moving the voltmeter along the wires until you figure out where the drop is. You might have something shorting out, a loose or dirty connector, or something is just wired wrong. I guess it is quite possible that what ever is wrong in your harness is also causing your starting issues.
One last thing, always take a wire brush to the battery terminals before troubleshooting any type of electrical problem.
As for the gauges reading different, hook a multimeter across the gauge terminals and see if they agree. Maybe the gauge is just off. If it isn’t, then you probably have some current draw through the harness that is causing the drop. Just start moving the voltmeter along the wires until you figure out where the drop is. You might have something shorting out, a loose or dirty connector, or something is just wired wrong. I guess it is quite possible that what ever is wrong in your harness is also causing your starting issues.
One last thing, always take a wire brush to the battery terminals before troubleshooting any type of electrical problem.
06-09-2010, 10:17 AM
#3
Thank you very much for the reply. I'm going to pull the dash this afternoon since my car is gutted and trace back the wiring like you said and see if I can find where the loss in voltage is at. I read up on that Ford starter solenoid and that sounds very promising. I will try jumper first from the S terminal to the battery and see what it does. If it works and I can't find anything wrong with the harness then I'll be adding the remote solenoid.
06-09-2010, 02:10 PM
#4
You need to test the circuits using the voltage drop method. What you are measuring is the amount of voltage consumed between two given points, in your case the first thing i would check is the Pos cable from the battery to the starter, so put the positive lead from your DVOM on the POS terminal of the battery, take the NEG lead of your DVOM and place it on the starter lug (big one) watch your meter while someone cranks it. Shouldnt be over .5v I would next check the ground side of the starter same way, one end of your meter on the starter housing, and the other on the neg terminal of the battery have someone start it. I would also check the voltage drop of the alternator to the battery wire, you could have a charging issue. Hope this helps, FYI a fully charged battery is 12.6V, 12V is a dead battery.
Mark
Mark
