1970 Blazer Aftermarket Gas Tank Sending Unit

[cpavelko]

Hey,
I was wondering if anyone knew of anyone who makes tanks like this? I am having trouble with the sending unit / fuel tank gauge. I tested the gauge it was fine but points to the 3:00 position past full. I double checked the wire and ran a test lead from the fuel tank plug on the fuse panel to the sending unit and still got nothing. I just pulled the tank today and will pull the sending unit to do some more tests probably tomorrow. Any suggestions? If the sending unit is bad, does anyone know where I can get another one?

[Ole Beater]

I have that exact same tank and the sending unit is the wrong ohm rating for the gauge. You need a 0-90 ohm unit. I just bought one from summit but haven't installed it yet.

[cpavelko]

Originally Posted by Ole Beater

I have that exact same tank and the sending unit is the wrong ohm rating for the gauge. You need a 0-90 ohm unit. I just bought one from summit but haven't installed it yet.

I thought that may be the case and would've been my next research after determining if the sending unit was bad or not. Thanks for saving me some time. i'll take a look at it tomorrow to confirm the resistance range. Could you send me a link to the one you bought. I found a few that are direct fit to tanks. Are you adapting one from another application?

[Ole Beater]

Actually that tank is a different tank than the one i have. I have one made by NWMP but looks very similar to the one you have.
http://www.nwmp.com/index.php?option...&id=4&Itemid=4
Here is the sending unit that i ordered from summit. http://www.summitracing.com/parts/VDO-226008/
It does not have a fuel line connection but it is adjustable for the depth of the tank that you install it into. If your tank doesnt have a fuel line connection then you may not be able to use this one.

[viking427]

Both Aero and NMWP make those extra capacity tanks, both companies have been making them for years and both companies have done minor revisions to them over the years. Unless there's a label or identifying mark somewhere on the tank, it may be tough to narrow down exactly which mfr and from which era it was made, of course it could be home-made too. Yes, 0-90 ohm is the sender you need, and adjustable to match the depth of your tank - just pick one (SW, VDO, Jazz etc.) with a sweep long enough to cover the depth for your tank so it reports accurately.

http://www.stewartwarner.com/Catalog/fuelsdrs90.html

http://www.nwmp.com/index.php?option...-gmc&Itemid=17 (37 gallons)

http://www.aerotanks.com/inventory/1139.html (40 gallons)

http://coloradok5.com/forums/showthread.php?t=275758 (73+ blazer, 43 gallons)

[Ole Beater]

I finally got around to changing the sending unit out with the Summit VDO 0-90 Ohm unit. The old one was a VDO also. Here are some pictures.

[Ole Beater]

There is a chart to tell you how to adjust the depth from the mount to the center line of the float hinge and the length to make the float arm. The screw holes are not equally spaced so the gasket only fits in one direction.

[cpavelko]

Thanks Ole Beater. I just got back into town here and took a look at the sending unit. It was a 90 Ohm but I tested it and it doesn't output the correct resistance. It is dated Feb 1983. Didn't think the tank was that old. Probably because the surface rust resembles a couple years of northeast weather / driving where I grew up. I'm just going to order the same unit you have from Summit.

[Ole Beater]

Its nice to have an accurate fuel gauge instead of having to guesstimate whats in the tank.

[cpavelko]

Hey,
Question. Got my sending unit installed in the tank and adjusted appropriately. Ready to install back the tank. Unfortunately the bolts used for the brackets that hold the tank in place used the two middle rear seat hold down holes in the floor. The brackets are big enough where I can drill new holes or mount another way. Unfortunately someone drilled out the square nuts that were welded to the body for the seats so I will need to figure out something else for that. How does your tank mount up? I am trying to think of the best solution so I can use the original seat holes for the seat and use other ones for the tank.

[Ole Beater]

There is a tab on both sides of the tank that allows it to bolt directly to the frame rails on the driverside and passenger side. They are L brackets about 6 inches long that are welded on. Not sure if it was built with them or added to mount the tank. My tank fits snug between the frame rails.

[cpavelko]

Thanks. I can see that now in this picture of yours.

Yeah it would be easier if mine had those. The brackets that are on mine are a little rediculous but do provide protection from off road scraping.