fuel gauge voltage regulator

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peter
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Re: fuel gauge voltage regulator

Post by peter » Wed Jun 18, 2014 1:50 pm

Is it still normally working, or is there now 12 volt on the gauges.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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mikeyfalcone
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Re: fuel gauge voltage regulator

Post by mikeyfalcone » Thu Jun 19, 2014 4:32 pm

Peter and Roman.

I tried the solder thing yesterday and despite my best efforts, it seems as though it sends a 12v to the output side. I tried soldering in different configurations as well. I also made sure everything that was supposed to be grounded was. I even placed the leads on the correct way, then the reverse way and still got 12V in and 12V out in both of those configurations.

that being said, my gauges WERE dead in the water, but the solder brought them to life. The problem is that instead of reading empty fuel and no temp, they spike to full fuel and top end of engine temp as well. I was excited to see it created a connection but I think for my particular unit it's just as ineffective.

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Roman
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Re: fuel gauge voltage regulator

Post by Roman » Thu Jun 19, 2014 5:20 pm

Bummer. Well..... we tried. At this point I defer to experts.:-)
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spl310
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Re: fuel gauge voltage regulator

Post by spl310 » Thu Jun 19, 2014 6:49 pm

Open it up and make sure that the points aren't fused
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Roman
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Re: fuel gauge voltage regulator

Post by Roman » Thu Jun 19, 2014 10:52 pm

Ah....... That reminds me of my years old repair. Thanks for refreshing my memory, Sid. I did get some 600 grit and cleaned the contact points as well.
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peter
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Re: fuel gauge voltage regulator

Post by peter » Fri Jun 20, 2014 12:57 am

Mine were last week also corroded and works strange,(up and down), but I was driving in the rain at that moment, after a day he was working normally.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Mainer311
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Re: fuel gauge voltage regulator

Post by Mainer311 » Mon Jun 23, 2014 11:17 am

Ha! I just had mine fail on me too. Glad to see there are 1,000 other posts on the same topic. I soldered all the rivets, sandpapered the contact points, and I found that the ground connection was very unreliable.
Jordan
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Roman
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Re: fuel gauge voltage regulator

Post by Roman » Mon Jun 23, 2014 12:43 pm

Mainer311 wrote:Ha! I just had mine fail on me too. Glad to see there are 1,000 other posts on the same topic. I soldered all the rivets, sandpapered the contact points, and I found that the ground connection was very unreliable.
Did it work for you? (the fix) Or am I the only one who has had success with the repair?
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Mainer311
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Re: fuel gauge voltage regulator

Post by Mainer311 » Mon Jun 23, 2014 12:47 pm

Roman wrote:
Mainer311 wrote:Ha! I just had mine fail on me too. Glad to see there are 1,000 other posts on the same topic. I soldered all the rivets, sandpapered the contact points, and I found that the ground connection was very unreliable.
Did it work for you? (the fix) Or am I the only one who has had success with the repair?
Sure did! The coil wire wraps around that thru-hole in the PCB, and the little "c"-shaped clip that clips over the wire was tarnished all to hell. My meter wasn't reading any continuity, so I pinched the c-clip smaller, and sanded the entire thing to expose bare copper again. I then clipped it back over the wire. After I installed the board back into the metal case, I soldered the c-clip to the metal case to ensure there was a good ground connection there.
Jordan
1968 SPL311-21773. Needs paint and some upholstery.
2012 Xterra Pro-4X, 4" lift on 34's, UCA's, pre-runner bumper. Member of the New England Xterra Off-road club.
1971 PL521, Dragon green. Stock L16 w/ 4 speed, lowered 3".

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Roman
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Re: fuel gauge voltage regulator

Post by Roman » Mon Jun 23, 2014 1:06 pm

YAY!!!! Another success!!
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peter
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Re: fuel gauge voltage regulator

Post by peter » Tue Jul 15, 2014 7:21 am

I tried the electronic one with the LM7808 but when the engine is of it shows the good value and when the engine is running it shows to much on the fuel gauge.
What also strange is that I don't need the ground for working.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Mainer311
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Re: fuel gauge voltage regulator

Post by Mainer311 » Tue Jul 15, 2014 7:33 am

peter wrote:I tried the electronic one with the LM7808 but when the engine is of it shows the good value and when the engine is running it shows to much on the fuel gauge.
What also strange is that I don't need the ground for working.
Use a multimeter and see what voltage you're getting out of it. The 7808 won't actually work without a ground. Maybe there is a short somewhere? Are you using caps on the input and output to level out any fluctuations in voltage?

Pin 2 (middle) is the ground:
http://www.mouser.com/ds/2/149/fairchil ... 325814.pdf" onclick="window.open(this.href);return false;
Jordan
1968 SPL311-21773. Needs paint and some upholstery.
2012 Xterra Pro-4X, 4" lift on 34's, UCA's, pre-runner bumper. Member of the New England Xterra Off-road club.
1971 PL521, Dragon green. Stock L16 w/ 4 speed, lowered 3".

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peter
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Re: fuel gauge voltage regulator

Post by peter » Tue Jul 15, 2014 8:42 am

I used a voltmeter and it is about 8 volt at the outside, without an with the ground.
I didn't look when I started the engine if the voltage was different, but that must be, otherwise it could not change.
I use also use the 0,33 and 0,1 caps on the in and output, the yellow wire is the plus, isn't it?
And the yellow/green the output.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Mainer311
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Re: fuel gauge voltage regulator

Post by Mainer311 » Tue Jul 15, 2014 10:25 am

The back case of the IC is actually a ground, so if the chip is touching metal, it will actually be grounded, w/o having the center pin grounded...so maybe it actually is, when you think it isn't? Just a thought, as I'm not sure.

The voltage out should always be 8 volts, despite what the voltage in is. That's the point of the regulator.

On '66, yellow is the input, and yellow/green is the 8V output.
Jordan
1968 SPL311-21773. Needs paint and some upholstery.
2012 Xterra Pro-4X, 4" lift on 34's, UCA's, pre-runner bumper. Member of the New England Xterra Off-road club.
1971 PL521, Dragon green. Stock L16 w/ 4 speed, lowered 3".

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Re: fuel gauge voltage regulator

Post by spyder » Tue Jul 15, 2014 12:22 pm

Center pin needs to be grounded for reference of the chip. You get unstable voltage without it.