1967 gas gauge issue

[67HEAVEN]

My new gas gauge is exhibiting the following behaviour:

- right after a fill-up the gauge shows full
- after 10 or 15 minutes of driving, the gauge drops to just under 1/4 full
- the gauge stays there until the next fill-up and never drops to empty even though the fuel does

Possible reasons:
- faulty gauge?
- faulty sending unit?
- faulty ground?
- other?

:confused

 

[vetteboy86]

Does it use a float? Could that be stuck perhaps?? Well on the bright side, you must be getting better gas mileage only burning a quarter of a tank regardless of how much you drive. :L

 

[stepinwolf]

My new gas gauge is exhibiting the following behaviour:

- right after a fill-up the gauge shows full
- after 10 or 15 minutes of driving, the gauge drops to just under 1/4 full
- the gauge stays there until the next fill-up

Possible reasons:
- faulty gauge?
- faulty sending unit?
- faulty ground?
- other?

:confused

Is it an original ( 179$ ) or a repop at about ( 80$ ). This would not the first time I have heard of this happening with the reproduction units

Stepinwolf

 

[67HEAVEN]

Does it use a float? Could that be stuck perhaps??

I thought about the float, but I doubt it's stuck since it reads full after a fill-up.

Then, as mentioned, it suddenly drops to 1/4 full. The float couldn't fall through the fuel to show that reading.

 

[67HEAVEN]

Is it an original ( 179$ ) or a repop at about ( 80$ ). This would not the first time I have heard of this happening with the reproduction units

Stepinwolf

Bob,

I'd have to go through my invoices, but I think I paid around $170 for it.

 

[stepinwolf]

One way to eliminate one of the solutions to the problem, is to have someone carefully stick their hand in the tank once it's low on gas, and slowly lift and lower the foam float, while you check the operation of the gauge with the switch on.

You might also want to try and run an additional ground wire from the ground tab on the sender, directly to the closest point on the frame.

The 170$ would have gotten you an original sender.

Stepinwolf

 

[tigernut]

- after 10 or 15 minutes of driving, the gauge drops to just under 1/4 full

With the size of your motor and the way you seem to be driving it, that usage doesn't surprise me.

 

[67HEAVEN]

With the size of your motor and the way you seem to be driving it, that usage doesn't surprise me.

Hah, hah, hah.

 

[ZRGator]

67Heaven, mine exhibits the same kind of bizarre behavior. Fill it up and it shows full for about the first 30 miles or so then it shows ½ full on the gauge then it jumps up to 3/4 then back to ½ again. I spoke to Midyear about this and he felt it was the sending unit. Hopefully he'll weigh in on this.


Of course there was that one really weird moment in the middle of that 360 I took when I had the composure to glance at the gas gauge (yeah, right) and it said empty. But I figure the centrifugal force had the gas slammed up on the side of the tank.

 

[IH2LOSE]

Bob as far as I know its all done with resisstance. Quanta was telling me that there were 2 different sets of resistance (Johnz will know this) and our gauges know at the higher reading to read full and progress to empty with the lower reading.

You know I have been playing with the 62 so long I forgot where the sender is on a midyear. Do you think I can get at mine to take a reading at full and empty with out removing the tank?

I am here to help

When I purchased my replacement tank from quanta I was suggested to use the more exspencive one and I did (even though the sock was included with the cheaper one) let me know if I can get a reading for you.

As we know if its done with resistance and you have a loose or coroded wire it will make it act funny.

 

[Viet Nam Vett]

I'm at work...But I do Have Tech Paper on the Gas Gauge which gives you trouble shooting info along with OHM"S read outs for the different Float locations 1/2/ Full /Empty ...etc. Some one here might have it and forward it to you. If you don't have it by tonight when I get home I'll send it to you.



It sounds Like a Possable Ground Thing..Since it is new...I don't think it's the gauge. But...As Kid_Again Says....." I may be wrong But I doubt It".......

 

[JohnZ]

My new gas gauge is exhibiting the following behaviour:

- right after a fill-up the gauge shows full
- after 10 or 15 minutes of driving, the gauge drops to just under 1/4 full
- the gauge stays there until the next fill-up and never drops to empty even though the fuel does

Possible reasons:
- faulty gauge?
- faulty sending unit?
- faulty ground?
- other?

:confused

Bob, that sounds pretty conclusively like a sending unit issue - have someone slowly move the float arm up and down through its full travel while you're watching the gauge and see how it reacts. Could be that the contact wiper arm connected to the float shaft isn't properly tensioned against the wirewound resistor and it's only making contact at the extreme ends of travel. Is it a Delco sending unit?

 

[67HEAVEN]

Thanks for the suggestions everyone. John, I forget if it was a Delco unit. I'll have to dig through my invoices to see where I got it. I'm almost positive it was from ZIP.

I guess the next step will be to empty the tank and see to the float action. All I need is a spare 10 minutes to drive around and empty the tank.

 

[rrhayden]

GM uses a zero to 90 ohms resistance curve. I can’t remember if zero is full or empty, however it is not important. The easiest way to determine if it is the gauge or sender is to remove the gauge wire from the sender. With it off, the gauge should read full scale either empty or full. If then short the same wire to ground the gauge should go full scale the opposite direction. If it does, your problem is in the sender, if not it is the gauge.

 

[Geek's 65]

Heaven - between the tan wire and ground it's 0 ohms full and 90 ohms empty. With the key off, between the black with purple stripe wire (12VDC with the key on) and the tan wire it's 0 ohms empty and 90 ohms full.

Geek

 

[65Fuelie]

Stepinwolf - Where can I find a sending unit for my 65 for $179? Paragon wants $220 for their OEM unit. I went to the AC Delco web site and couldn't find a listing for their sending unit. I have tried and returned the $79 units from CC and LIC, both were not even worth the effort of ordering.

65 Fuelie

 

[RodsnRides]

rr hayden is spot on here. Here is what I have - from Car Craft, December 2000 (yeah, I know...).

With the ignition key in the ON position, remove the sending unit wire and check the gauge. It should read over Full. Grounding this wire should cause the gauge to slowly fall to Empty. This will confirm gauge and wiring.

Check sending unit resistance. Empty should be 0 ohms, full will be 88 ohms resistance.

Hope this helps...

Rick

 

[paul67]

This is the Delco unit. But it is about $220.00!

http://img.photobucket.com/albums/v155/Buffy97/fuel007.jpg

 

[stepinwolf]

This is the Delco unit. But it is about $220.00!

http://img.photobucket.com/albums/v155/Buffy97/fuel007.jpg

The last original Delco unit's available were sold by Corvette Specialites of MD, and his ( Brian's ) discounted price was around 170$ at the tiime. I have since been informed that they are no longer available, and that the only senders that can now be had are the @#$%&* Asian imports.

Stepinwolf

 

[65Fuelie]

Thanks Guys for the information. I guess I will "bite the bullet" and order their

OEM sending unit for $230.00.

65 Fuelie