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Veteran
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| The gas gauge in my 57 Saratoga has been acting up as of late. I know it has a good ground and I'm planning on putting it up on the lift and investigate it further this week (gauge, sending unit, wiring etc.).
That being said, if it turns out to be the sending unit, who makes (or sells) a quality replacement piece ? It's next to impossible to get an accurate aftermarket one for the late '60's cars these days and I wish to avoid that fate if possible.
Also, is there a consensus on the ohm range of a correctly functioning unit ? I did a search and came up with conflicting answers. Thanks |
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Expert 5K+
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Location: Lower Mainland BC | 5wndwcpe - 2016-12-07 2:06 PM The gas gauge in my 57 Saratoga has been acting up as of late. I know it has a good ground and I'm planning on putting it up on the lift and investigate it further this week (gauge, sending unit, wiring etc.). That being said, if it turns out to be the sending unit, who makes (or sells) a quality replacement piece ? It's next to impossible to get an accurate aftermarket one for the late '60's cars these days and I wish to avoid that fate if possible. Also, is there a consensus on the ohm range of a correctly functioning unit ? I did a search and came up with conflicting answers.Thanks
"..one of the guys suggested that we use a universal sender available from J.C. Whitney. It has the perfect range of 10 ohms to 78 ohms that our vehicles crave but it just will not fit very well"
REFERENCE: (DIY on converting the JC Whitney sender (no longer available) to older 50's Mopar): http://www.ply33.com/Repair/fuelsender.html
A little searching also turns up this:
http://www.classiccarautoparts.com/gastank_sending_units.html
HTH (and good luck) |
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Expert 5K+
Posts: 9647
Location: So. Cal | Sorry Dave, but the '57 cars don't use a 10-78ohm sender. My '57-'58 cars use a 15-210 ohm range. I would bet that Pete's does too and it should be the same for '59. Just purchase this sender on Ebay. I did and it works really well and is quite cheap. It makes the gauge read perfectly when full and empty, but it does tend to stay longer at full, and swing faster once you get to half tank. So the gauge isn't as linear as it probably should be, but this is really minor.
http://www.ebay.com/itm/1957-58-59-Chrysler-Mopar-Fuel-Tank-5-16-Se...
Edit: Oh, and these guys advertise a lot of other ohm ranges for the same cars too, which don't work, so make sure that the title explicitly says 15-210 ohm, or it probably isn't.
Edited by Powerflite 2016-12-07 7:26 PM
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Expert
Posts: 3774
Location: NorCal |
I agree, the 10-73 ohm sender is for later models. |
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Veteran
Posts: 131
| Thanks fellas !
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Veteran
Posts: 131
| Okay, that did not pan out so well. I had ordered the part from the eBay seller Nathan linked to and testing outside of the tank, it pegged the gauge immediately. It does not matter where you position the float. I checked it with a VOM and it was pretty erratic, somewhere between 8 and 118 ohms. I sent the seller a note but they've yet to respond. Should this go south, any other sources ?
I don't mind paying for a quality piece, but I dropped the tank to install this and the car is taking up the lift, so I'd like to get this buttoned up. |
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Expert 5K+
Posts: 9647
Location: So. Cal | You do need to keep the sender in the vertical position when testing it out. If you rock it side-to-side at all, it will give erratic results. I hold the sender in the right position as if it were installed in the tank and use a pencil or other rod to lift it as straight as possible. But you should at least be able to see the 200ohm value. If not, you may have a bad or wrong part. |
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Veteran
Posts: 131
| Yep, I had it clamped in a vice so as not to side load the float arm.
I found a few NOS ones but geez, $295 for a sending is a bit too salty for me. |
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Veteran
Posts: 131
| UPDATE: Okay, I found the new replacement unit would max out at 128 ohms or so. The vendor graciously sent me another unit, but unfortunately it maxed out at 130 ohms. The advertised range was 15 to 200 ohms. Either one of the pieces would not allow my gauge to read below a quarter of a tank, so it was back to the drawing board.
What I found on my original, 59 year old sending unit was a shaky ground and a saturated float. What I used for the float was (2) Model T replacement pieces, trimmed to fit.
http://www.snydersantiqueauto.com/gauge-float-only
As for the ground, I previously had soldered a wire from the pickup tube (outside the tank) to a wire and attached it to the frame with an eyelet. This was fine and dandy, but what was also needed was a ground running (on the inside of the tank) from the float arm to the pick up tube. The sending unit is in essence a variable resistor. The coil side is connected to the center tap and goes directly to the fuel gauge. The wiper side is connected to the float arm and grounds to the body through the little bushing it rides on. If that gets worn or crapped up, your ground becomes hinky. I used a piece of 1/8" tinned braid and gave it a big enough loop so as not to interfere with the up and down motion of the arm itself.
https://www.amazon.com/dp/B003HGHQYC/ref=biss_dp_t_asn
The pick up now tests good outside of the tank, re-installing tomorrow.
On a side note, I knew I was going to have issues with re-sealing the sending unit as my gasket was toast. I ran across this and thought I'd give it a try.
https://www.permatex.com/products/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant/
Edited by 5wndwcpe 2016-12-26 5:58 PM
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Expert 5K+
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Location: So. Cal | That's really odd. I purchased a couple of these senders about a year ago and they worked great right up to 210 ohms. James Rawa also bought some and found the same thing. I don't know why they can't get it right now.....That's frustrating. |
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Veteran
Posts: 131
| I guess they are hit and miss. I did test the gauge with a 250 ohm pot and it registered full at 180 ohms and empty at 20 ohms so there was no way either of the aftermarket ones were going to work. At least not this batch. |
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fuel sending unit source
