Gauges, Gas Oil.

77 cj5 , new tank, sending unit, gauge cluster, wire checks out fine, when the key is turned on it goes to full and stays there, grounds are good.....similer problem with oil pressure, on second new sending unit, added a new gauge today, turn key on and it goes to full pressure and stays there after it is started, grounds are good, and sending wire also.

 

Sure the senders and gauges are matched?

 

Who's the manufacturer of you gas sending unit if it's Crown or Omix not unusual for those not to work. I finally bought an MTD gas sending unit made here in the USA and have had no problems.

 

I think Omix, but I hope I wasnt missing something simple. everything was ordered for a 77 cj5, so it should match, I agree with crown a Omix being trash.

 

DID you test it before putting it in? did you adjust the swing?

 

The omix gages are no good if you look you can find nos ones get a name brand sending unit for the oil and an mts sender for the tank.are the wires to the senders new? If the wire is grounded the gage will peg full.

 

No I did not test.

 

The wires test good and I even ran a temperary one to double check, and I get the same result...Full...I took sending wire off tank and grounded it and I get the same result FULL. Ill try the same with the oil sender to see what happens.

 

do they peg with no sender hooked up?i recall the omix ones had a bunch that were wired wrong.

 

This... Wired wrong from the factory..

 

I had a 77 cj5. Gas gauge didn't work. There are at least 2 different ones where the sender and gauges were not matched correctly. I got mine from the dealer in 1990 and had to get another one. You need to figure out the ohm range and match it.

Could also be the the gauges or sender are faulty too though.

 

both the oil and gas ,do not do anything with sender unhooked.

 

Isolate the senders from the gauges so you can test them separately. Both the oil and temp gauges respond to changing resistance from their senders. Look at pages 3-57 and 3-58 in the '77 TSM. Get some fixed resistors (or a potentiometer) and some clip leads and substitute resistors for the senders. Disconnect the gauge and measure the resistances from the senders with your multimeter. This will identify if the problem is the gauges or the senders.

 

Ok, I removed sending unit on gas tank, hooked it back up and moved float by hand, in down position it reads empty, start raising and it goes straight to full. took it apart and theres not a whole lot to it. who sells a good one? I have been satisfied with Summit.

 

Test the gauges with fixed resistors before you condemn the sender.

 

Got it, it was the brand new omix gauge cluster, gas gauge was defective. Luckily 4 wheel parts took it back, thanks.