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Bench Testing Fuel Sender and VDO Gauge

Beamin

Platinum Level Sponsor
I’m about ready to reinstall the fuel tanks. Got them all cleaned up, painted outside, POR-15d the insides. Got a couple questions:

1) Is there a proper bench test for a stock SV fuel sender unit. I’ve taken some resistance readings…24 ohms on the low end, 340 ohms on the high end. I have no idea if those values indicate a properly functioning sender.

2) Most of the gauges have been converted over to VDO. The fuel gauge is still a stock unit, but I’d like to swap that out for a matching VDO gauge as well. Several options are shown on VDOs website, some listed by specific manufacturer’s sender units (Ford, Chevy) and some with ohm readings. None match the resistance measurements I came up with. Has anyone made this swap? If so, what gauge? Were any other electrical modifications necessary?
 

Aladin Sane

Diamond Level Sponsor
I am going about it the other way. I have a new set of VDO gauges, and I will be retrofitting a modern VDO sender to fit the sunbeam tank.
 

husky drvr

Platinum Level Sponsor
I’m about ready to reinstall the fuel tanks. Got them all cleaned up, painted outside, POR-15d the insides. Got a couple questions:

1) Is there a proper bench test for a stock SV fuel sender unit. I’ve taken some resistance readings…24 ohms on the low end, 340 ohms on the high end. I have no idea if those values indicate a properly functioning sender.

2) Most of the gauges have been converted over to VDO. The fuel gauge is still a stock unit, but I’d like to swap that out for a matching VDO gauge as well. Several options are shown on VDOs website, some listed by specific manufacturer’s sender units (Ford, Chevy) and some with ohm readings. None match the resistance measurements I came up with. Has anyone made this swap? If so, what gauge? Were any other electrical modifications necessary?


Andy,

In an earlier thread, Mike H. (hartmandm) posted these values for a sIV -

" . . . a series IV based on previous posts. The stock fuel sender puts out ~250 ohms for Empty, 18 ohms for Full, and 68 ohms for half-full." You should review that thread - think it discusses most of your questions.

https://forum.sunbeamalpine.org/index.php?posts/185634/

It's an analog system driving a heated bi-metallic strip. The end points may not be exactly critical.

Hopefully others with more knowledge will chime in to help.

Have fun,
 

loose_electron

Donation Time
I used Speed Hut instruments. For those, you program them, once when the tank is empty and once when the tank is full.

I'm surprised VDO doesn't do the same.
 

Beamin

Platinum Level Sponsor
series IV based on previous posts. The stock fuel sender puts out ~250 ohms for Empty, 18 ohms for Full, and 68 ohms for half-full." You should review that thread - think it discusses most of your questions.

https://forum.sunbeamalpine.org/index.php?posts/185634/

I don’t know why I struggle so much when searching for information on this site. Thanks for the link

I looked at some options for the fuel interface modules mentioned in that post. Seems pricey, although in the grand scheme of things, now is not the time to start worrying about a few extra dollars here and there. But it does seem a little silly to spend $100+ on a module that relies on a 55 year old sender, so maybe it makes sense to find a VDO sender that works.

I am going about it the other way. I have a new set of VDO gauges, and I will be retrofitting a modern VDO sender to fit the sunbeam tank.

Aladin, have you figured out the best sender to use and how you’ll install it? VDOs website is a little light on documentation, so its hard to figure out which unit will work best.
 

Aladin Sane

Diamond Level Sponsor
I have not picked the sender yet, but whatever I do will involve modifying the mounting flange to fit the sunbeam tank.

I need the car back in hand so that I can get measurements off the tank before I pick a sender.
 

hartmandm

Moderator
Diamond Level Sponsor
See the fuel temp gauges document from http://wp.mhartman.net/home/cars/sunbeam/alpine/info.

I've checked out VDO temp senders to match to a stock Alpine temp gauge and they have a few different resistance curves. (Sunbeam fuel and temp gauges are the same internally.) VDO does have a temp sender resistance curve that is a pretty good match to the Alpine. They probably support the same curve for a fuel gauge. Look for a fuel gauge that is similar to the specs Don posted above (and are also in the fuel temp gauges document).

Mike
 

Barry

Diamond Level Sponsor
The fuel gauge sender that came with my S-V measures about 237 ohms in the empty position and about 35 ohms in the full position which is very close to the 240 / 33 Stewart-Warner standard.

Most gauge suppliers have a fuel gauge that is suitable for use with a 240 / 33 Stewart-Warner sender.
 

Beamin

Platinum Level Sponsor
I ended up going with a universal VDO 0-90ohm sender and matching gauge. Required very little modification to the stock fuel tank - I just needed to remove top locking flange and open up the hole a bit.


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Aladin Sane

Diamond Level Sponsor
Interesting. I had planned on modding the sender flange to match the tank. I see you went the other way.

Can you share which sender you selected?
 
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Beamin

Platinum Level Sponsor
After reading your suggestion, I had thought about going that route. But after taking a closer look at how the stock tank was constructed, I realized that it would be pretty easy to remove the locking flange from the tank, leaving a flat surface to mount the new sender. Took less than 30 minutes to cut off the raised lip, grind down the spot welds and remove the entire piece, then enlarge the hole a bit. With VDOs universal senders, you don’t need to worry about fabbing a matching bolt pattern with nuts. The fuel tank gets sandwiched between two metal mounting disks.
 
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