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Fuel & Temp Gauge Troubleshooting
- Thread starter hartmandm
- Start date
It has been a while, but Tom and I have finally published an updated fuel & temp gauges document: http://mhartman.net/files/sunbeam/fuel & temp gauges.pdf
There is quite a bit of new content in the document. (Note: it still only covers the series III to V gauges.)
Thanks,
Mike
There is quite a bit of new content in the document. (Note: it still only covers the series III to V gauges.)
Thanks,
Mike
loose_electron
Donation Time
A quick comment on getting resistors for test setups now that Radio Shack is mostly gone -
EBay is your friend here for quick, cheap and easy.
77 ohms is not a standard value, but 75 ohms, in a 2W or 3W rating should work just fine for this testing.
A couple dollars on EBay gets it done. There are a lot of online component vendors but they cost more money with shipping and minimums. For this sort of thing get it from EBay.
As for the instruments, well, I cheated. I got Speed Hut everywhere now.
Worse yet, I got a GPS driven speedo. Our secret!
EBay is your friend here for quick, cheap and easy.
77 ohms is not a standard value, but 75 ohms, in a 2W or 3W rating should work just fine for this testing.
A couple dollars on EBay gets it done. There are a lot of online component vendors but they cost more money with shipping and minimums. For this sort of thing get it from EBay.
As for the instruments, well, I cheated. I got Speed Hut everywhere now.
Worse yet, I got a GPS driven speedo. Our secret! 
This is terrific! Great work Mike and Tom!
Billm
Gold Level Sponsor
Mike a great write up on the gauge problems. I will pull my temp gauge and try to adjust it. My Ford sending unit pegs the temp gauge when the water temp is 185 degrees. I was going to try a device called Meter Match made by a firm called TechnoVersionsLLC. Not being well versed in electronics, the MeterMatch allows for calibration of your gauge. I would check there website for more info. I have no affiliation. Just looking for an accurate temperature of the engine. Bill
Bill,
Do you know what resistances your Ford sender generates at various temperatures? Maybe an Internet search could find that info. If not, you could put the sender in a pot of water and measure the resistances at various temperatures. Then you'd have a starting point for knowing the discrepancies between the sender and gauge. Maybe a simple resistor in series to the sender could at least get the gauge to be accurate at the normal operating temperature.
Mike
Do you know what resistances your Ford sender generates at various temperatures? Maybe an Internet search could find that info. If not, you could put the sender in a pot of water and measure the resistances at various temperatures. Then you'd have a starting point for knowing the discrepancies between the sender and gauge. Maybe a simple resistor in series to the sender could at least get the gauge to be accurate at the normal operating temperature.
Mike
Bill, Please follow Mike's suggestion before trying to adjust the gauge. The adjustments noted by Mike in the document are part of the gauge design and are meant only for minor adjustment and are almost certain to not have enough adjustment to accommodate a different sender.
The MeterMatch looks interesting and at around $50 or so might be quite practical. It seems to me that the MeterMatch-VR might be the best fit. But ask them if it has enough output to drive a gauge that requires about 125 milliamperes at full scale.
What Series is your Alpine.? Assuming it’s an S3 or later have you already verified that the voltage stabilizer is working and putting out 10 v dc or equivalent?
Edit: previous posts indicate you have a Tiger drivetrain. Presumably that includes a Tiger sender. If so then your problem may be a bad sender or bad voltage stabilizer or bad grid for the stabilizer.
Tom
The MeterMatch looks interesting and at around $50 or so might be quite practical. It seems to me that the MeterMatch-VR might be the best fit. But ask them if it has enough output to drive a gauge that requires about 125 milliamperes at full scale.
What Series is your Alpine.? Assuming it’s an S3 or later have you already verified that the voltage stabilizer is working and putting out 10 v dc or equivalent?
Edit: previous posts indicate you have a Tiger drivetrain. Presumably that includes a Tiger sender. If so then your problem may be a bad sender or bad voltage stabilizer or bad grid for the stabilizer.
Tom
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Billm
Gold Level Sponsor
Tom I do have a Ford sending unit. You are correct. From what I know, the Body is 67 Alpine with a Tiger drive train transplant with trans tunnel, rear axle front suspension, rack and pinion steering...... I will pull the sending unit and see what the values are. Electricity gives me. A big headache! The info from this forum is great. Just went thru both doors on my car, new channels, degreased the gears, regressed the gears new weather stripping...... used the info from this forum. Next is exhaust system. Bill
Easiest thing to check first is the voltage stabilizer. pull the wire off the connection on the sender and measure the voltage on that wire. It should be 10 V if you have an aftermarket stabilizer or 12 v turning on and off about 2 times per second if it's original. If it is a steady 12.6 to 14 V that is your problem.
Tom
Tom
'Beam, we're working on it. Dan Richardson loaned me a pair of early gauges and I have tested them and we will report soon. Interesting things I have found. Number one surprise is that with the early gauges, the Temp and Fuel have significant different internal differences.
Tom
Tom
Boobtube
Silver Level Sponsor
Well, I've followed your instructions and have a head scratcher for you. Both meters barely move so I first measured the voltage from the stabilizer output and it does what you say--fluctuates from 12 to zero rapidly. I then put this voltage straight to each meter separately. They rise as expected. I then wired them in series as shown in the guide. Both move about 1/8 of the way up and then fall and sit at about zero(not the same as no voltage but close). I then wired a 75 ohm resistor to each separately in place of the senders and each did the same thing--rises to about 1/8 up and then drops. I measured the resistance of each meter--62 ohms for the temp and 68 for the fuel, which is probably good enough. So what could be the problem at this point? I'm guessing that even though I saw the fluctuation on the output of the stabilizer, it must not be working correctly. I don't have a 10 volt supply to test the meter with a different source other than the stabilizer. It's odd that the meter rises fully with the stabilizer feeding the meter without the sender in the line if the stabilizer was bad, unless it fails after it begins the fluctuation and I'm only seeing the initial rise before it begins to fluctuate. Any ideas would be helpful.
Are you seeing approximately 12.6V at the stabilizer "B" connection when the ignition is on?
I'd try by-passing the voltage stabilizer, so the gauges receive 12.6V DC continuously. With the gauges wired in series to each other, and receiving 12.6V DC continuous, they should read higher than the picture in the PDF.
To by-pass the stabilizer, you can temporarily remove both connectors at the "B" connection. Then try connecting each one of the removed connectors to the "I" connector. Only one of the two removed connectors will be hot when the ignition is turned on. So you have a 50-50 shot of getting it right the first time.
Mike
I'd try by-passing the voltage stabilizer, so the gauges receive 12.6V DC continuously. With the gauges wired in series to each other, and receiving 12.6V DC continuous, they should read higher than the picture in the PDF.
To by-pass the stabilizer, you can temporarily remove both connectors at the "B" connection. Then try connecting each one of the removed connectors to the "I" connector. Only one of the two removed connectors will be hot when the ignition is turned on. So you have a 50-50 shot of getting it right the first time.
Mike
Ken Ellis
Donation Time
Mr. Tube, (since we're not on a "first name" basis ),
Try your resistor test with a fresh 9-volt battery as the source, instead of the voltage stabilizer. It could be that the stabilizer can't supply enough current to make things go, but the voltage characteristic is correct. (Never looked at the internals of that unit, so I may be off-base...)
But in any event, a 9-volt should make things go for a short while. Just connect negative to ground, and apply your clip leads. (If you want, you can even put a AA, C, or D in series to get the volts where they need to be. Just takes more clip leads or tape.)
),Try your resistor test with a fresh 9-volt battery as the source, instead of the voltage stabilizer. It could be that the stabilizer can't supply enough current to make things go, but the voltage characteristic is correct. (Never looked at the internals of that unit, so I may be off-base...)
But in any event, a 9-volt should make things go for a short while. Just connect negative to ground, and apply your clip leads. (If you want, you can even put a AA, C, or D in series to get the volts where they need to be. Just takes more clip leads or tape.)
Beam, He has SIV. I know that from previous posts by him, but also can tell he has later series gauges by the fact that he is trying to follow instructions on later series and the fact that he measures each gauge about 65 ohms.
Ken, a 9 V battery will be about 8 volts when loaded with 100 mA or so. Each gauge takes about 130 mA at full scale, about 75 mA at mid scale . Better to just use the direct vehicle battery voltage for reasonable test, as suggested by Mike.
Boob, you are seeing some strange behavior. I am puzzled. What was the situation that is causing you to troubleshoot the system?
Edit- On re-reading your post it seems your gauges were reading low. You say the stabilizer output was switching fast. At 12.6 V, with engine and gen not running, the stabilizer should be switching on/off about 1-2 times per sec. From your description, I suspect your stabilizer is defective, switching too rapidly and not putting out enough avg voltage.
Tom
Ken, a 9 V battery will be about 8 volts when loaded with 100 mA or so. Each gauge takes about 130 mA at full scale, about 75 mA at mid scale . Better to just use the direct vehicle battery voltage for reasonable test, as suggested by Mike.
Boob, you are seeing some strange behavior. I am puzzled. What was the situation that is causing you to troubleshoot the system?
Edit- On re-reading your post it seems your gauges were reading low. You say the stabilizer output was switching fast. At 12.6 V, with engine and gen not running, the stabilizer should be switching on/off about 1-2 times per sec. From your description, I suspect your stabilizer is defective, switching too rapidly and not putting out enough avg voltage.
Tom
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