Fuel Level Sending Unit

Lightingrod · #1 (**permalink**) 04-30-2013, 07:41 PM

What type of fuel level sending units were used with the CR-II fuel tanks (1991 kit)? 240-33, 16-158 or 0-90 ohms? I tried to take an ohm reading but it's coming up pretty much like an open with a full tank of fuel. It works but I’m not sure how accurate it is. It always seems to sit on full forever and then drop real quick. I have never let it get below about ½.

I guess I may just have to pull the dang tank! When I get it figured out I’m ordering these gauges.

Auto Meter Cobra Gauges - JEGS

soulman · #2 (**permalink**) 04-30-2013, 07:52 PM

Quote:

Originally Posted by Lightingrod

What type of fuel level sending units were used with the CR-II fuel tanks (1991 kit)? 240-33, 16-158 or 0-90 ohms? I tried to take an ohm reading but it's coming up pretty much like an open with a full tank of fuel. It works but I’m not sure how accurate it is. It always seems to sit on full forever and then drop real quick. I have never let it get below about ½.

I guess I may just have to pull the dang tank! When I get it figured out I’m ordering these gauges.

Auto Meter Cobra Gauges - JEGS

Or you could use my type of fuel sender unit on my Kirkham. a flexible wooden dip stick about a meter long !

Soul.

mickmate · #3 (**permalink**) 04-30-2013, 07:58 PM

What kind of fuel level gauge?

Lightingrod · #4 (**permalink**) 04-30-2013, 08:14 PM

Currently pretty cheap looking VDO but I couldn't find a p/n on it!

tcrist · #5 (**permalink**) 04-30-2013, 08:32 PM

When I had to replace mine I used a VDO #301-303 VDO 301-303 VDO Series 1 Gauges

Lightingrod · #6 (**permalink**) 04-30-2013, 08:39 PM

Quote:

Originally Posted by tcrist

When I had to replace mine I used a VDO #301-303 VDO 301-303 VDO Series 1 Gauges

Those look a lot better than what's in mine and a couple of options as well!

Tommy · #7 (**permalink**) 05-01-2013, 05:08 AM

Lightningrod,
If all you want to do is match the ohms of your new gauge to the old one, here's a way to do that. Go down to your Radio Shack or similar store and buy a cheap 90 ohm resistor. Disconnect your old gauge from the tank sender and wire it so the resistor is in the circuit where the tank sender would normally be. This gives you a known input the same as your tank sender would if it were at the level where it reads 90 ohms. On the 33-240 gauge that will show as about 2/3 full. On the 16-158 gauge it will show about half full, and completely empty on the 0-90 gauge. As most aftermarket gauges are of the 33-240 variety, that's the one I would expect to see.

BTW, if they don't have a 90 ohm resistor, you can wire two or more lesser resistors together in series as long as they add up to 90.

FWB · #8 (**permalink**) 05-01-2013, 01:11 PM

i dunno if you have changed them but the gauges shown in the pics in your album look like stewart-warners to me.....if they are SW then its a 240-33...

mickmate · #9 (**permalink**) 05-01-2013, 07:33 PM

The VDO's I've tinkered with are also 33-240.

Lightingrod · #10 (**permalink**) 05-02-2013, 03:46 AM

They are CHEAP-O VDO's, all plastic!

Tommy, I had the same idea to use a resistor but that will only tell me what the current gauge is. My concern is that it may NOT be correct! I went ahead and used a variable resistor and took readings at empty and full. The current gauge is a 0-90!

I would be a "Happy Camper" if the signal wire was reading 90, 158 or 240 ohms but it's reading OPEN! As I said it seemed to stay at full forever and If I remember right it would take 10 or more gallons to fill it from 3/4's of a tank! So, bad or maladjusted sending unit? What type, no way to tell for sure with the information I have!

I really like the Autometer Cobra gauges but I want to be sure before I drop $650.00 on them only to find out my sending unit is a 0-90 ohms which the Cobra series don't support! I'm planning some road trips in the future so a fairly accurate fuel gauge is important! I guess I'll just hold off ordering until I can pull the tank and make SURE!

Thanks Guys!

:-)

mickmate · #11 (**permalink**) 05-02-2013, 04:36 AM

So what is your current sender? Impedance and type (inductive or mechanical)?

Lightingrod · #12 (**permalink**) 05-02-2013, 04:56 AM

No idea, that's why I'm going to wait until I can pull the tank and check! I bought the car already built and there are a lot of things that were done half-azz at best! Just do them one at a time!