Fuel Gauge

[dan lephart]

OK I checked the ohms at the tank connector, it reads 32.3 ohms with the tank nearly empty. Shouldn't it be closer to 0 ohms when empty? Cleaned the connectors at the tank and behind the fuel gauge on the dash, no change. Gauge reads nearly half a tank when I know it is nearly empty. Sending unit need replaced ??

 

[PhilM]

Yes, it will read near zero when empty. Couple things: make sure the actual fuel level you have in there, no guessing. Siphon some out and take the measurements, the resistance should drop. If it doesn't change the arm is stuck. You can sometimes repair the units but it is often just as easy to get a new one and be done with it. Recheck the connector as they are prone to fail as well.

Phil

 

[6=8]

There are some in-tank baffles designed to keep the fuel near the pickup as the level drops. It is possible the plastic baffles have come loose and are interfearing with the sending unit.

A similar problem may be related to a recent pump replacement, where the sending unit/pump assembly is clocked (Rotated) where the float is dragging on the sides of the in-tank baffles.

Or, like you said, maybe it just needs to be replaced!

 

[84GNGary]

If you have an orange connector on your sending unit I have instructions on how to fix it here http://home.comcast.net/~84gngary/sendingunit1.html .
I just fixed an 86/87 sending unit last week, they are repairable so save your $300. I have to get the pics and put them on the site when I get a chance. But there is a spring that is used to make the ground connection from the cover plate to the float arm. You have a poor connection between the two causing you to get a higher resistance reading. Hook up the ohm meter to it while it is out and wiggle the float arm around then move it up or down, your ohm reading will be all over the place because of the oxidation.
Pry up the three tabs that hold the cover plate (has the pink wire attached to it) in place then lift the cover off. The spring will be on the swing arm shaft. With a piece of scotch brite clean any oxidation from where all these parts contact one another, float arm, spring, inside the cover plate, outside the cover plate by tabs and the tabs. Also clean the contact on the float arm that rubs against the wire coil. INSIDE THE COVER PLATE IS A WIRE COIL, DO NOT USE SCOTCH BRITE ON THIS OR YOU WILL RUIN IT. You can clean the wire coil with a pencil eraser or electric contact cleaner only. Now give the spring a little stretch and put everything back together. Attach an ohm meter and check your readings while moving the arm up & down and wiggle it around, you should now have more steady readings. In the full position should be around 100 ohms, empty is around 5 ohms.
The one I fixed had 110 ohms full and 10 ohms empty after cleaning it. Before it was reading around 25 - 30 ohms empty which will give you about a 1/4 tank on your gas gauge.


Gary

 

[GN Bob]

If your sender is unrepairable like mine was, order a universal GM 0 - 90 ohm sender from J.C. Whitney for < $20.

All I did was swap the new white plastic sending unit from the J.C. unit onto my stock hanger (it has the same screw hole spacing and attaches right onto the hanger), form the new float arm and all is working well.

Do yourself a favor and perform a resistance check before re-hanging the tank to be sure you get an accurate empty & full reading on your dash guage.

Bob

 

[dan lephart]

Thanx For All The Info!!!!!! Sounds Like The Jc Whitney Way Is The Best Deal. What Is The Part Number For The Universal Sender?

 

[crzy81regal]

im not positive on 85-87 gn's but my 81 regal t use a 25 - 90 ohms sender and at the 32 ohms you would have been basically empty...you better do some more research before you order the wrong parts from jc. only really know this because ive just installed all new autometer phantom gauges.

josh

 

[GN Bob]

Fuel level sender

Thanx For All The Info!!!!!! Sounds Like The Jc Whitney Way Is The Best Deal. What Is The Part Number For The Universal Sender?

Hope this link works:

http://www.jcwhitney.com/autoparts/...Id-100000163634/Pr-p_CATENTRY_ID:100000163634

If not, its PN ZX132950R for $18. I used the 0 - 90 ohm unit for my 87 GN.

Its a real easy swap. I was quoted $150+ for a used one so its like getting 3 tanks of premium free.

Good luck.

Bob