Fuel sending unit problem? 95 6.5 diesel Tahoe We just installed a new sending unit i

[jrsavoie]

Fuel sending unit problem? 95 6.5 diesel Tahoe
We just installed a new sending unit in the Tahoe. Added 5 gallons of fuel. Hit the key and the gauge goes down hard - way below empty.

I spent extra money on an AC Delco sending unit. It was made in fricking china.

Did I get a bad sending unit? Any ideas?

The sending unit would have had to just go bad when we put the sending unit and new fuel tank in. It worked somewhat before. It would only go to 3/4 tank when full and go to empty way before its time.

The sending unit is in the tank. A learning experience for me that I didn't want. Seems like it would be a dang good idea to plug the sending unit in and move the float before installing it in the tank and installing the tank. I learned years ago - the hard way - to test new alternators and starters before installing them. I must be slipping

The pump is good. On a diesel the pump is not in the tank

There is no ground from the sending unit to the frame. There was no ground on the old unit either. all our other 6.5 diesels have a ground to frame off the sending units. Neither the old nor the new sending units had a ground wire.
There is a 2 wire plug to the sending unit - I assumed power line in and line out to the gauge. Not sure exactly how they work.
I am planning to hook a ground jumper wire to the tank tomorrow. Don't know if I can get to the sending unit to hook the ground directly to it, with out dropping the tank at least some

Any advice would be appreciated

 

[DRAGGIN95]

Man that suck's, I would probably drop the tank again and do what you said, and move the float arm through it's travel to see if it's working, I know in our burb and 2dr 5 gallon's in a completely empty large tank isn't enough to even make the float move.

 

[jrsavoie]

But it doesn't abnormally move the gauge way past empty to the south end.

We filled the tank and it only goes to half. I need to find out how to do diagnostics to find out f it's the sending unit, gauge or wiring

 

[firefighter_2319]

But it doesn't abnormally move the gauge way past empty to the south end.

We filled the tank and it only goes to half. I need to find out how to do diagnostics to find out f it's the sending unit, gauge or wiring

on the older models you could take the wire off the sending unit and with the key on of course and ground the wire out. if the gauge moves then its not the gauge. i would say that if you did that now it would be the same. i would check your grounds going from the tank to the sending unit.

 

[jrsavoie]

I did not check to see what the gauge read before starting messing with it today- I should have

The last time we checked it read about 1/2 tank.

I tested resistance on the sending unit -46.2 ohms - which I'm guessing would be about 1/2 tank. The tank should be near full unless I'm getting really poor fuel mileage. It's only gone about 8 miles after being filled.

I tested voltage to the sending unit - 8 volts

After these tests the gauge read empty - it may have been reading empty before we started - No way of knowing as we didn't check the gauge before we started this morning.

I ran a ground from the battery to the ground on the sending unit. I made jumper plug with the ground accessible to add the ground from the battery. I cleaned and copper-coated the ground connection.

The gauge now reads empty all the time.

I'm ordering a new sending unit. And I'm plugging it in and testing it, before I drop the tank.

Any recommendations for sending units? I haven't started looking again yet. I will not order another AC Delco.

And their customer service sucks. They send you to a phone number. When you call it the people inform you that they are not associated with AC Delco and are a private company that helps on all vehicles for something like $3 a minute.

I used to use and recommend AC Delco parts for most applications. No more - this made in China sending unit that doesn't seem to work has put me off on them.

If I have to buy Chinese garbage, it just as well be cheap Chinese garbage as apposed to expensive Chinese garbage