Sign in to follow this  
fast_dave

Recently Restored 65 Riv GS is having "issues" with fuel level indication...

Recommended Posts

fast_dave    10

My bro-in-laws 65 Riv GS (with factory A/C)  had a frame off restoration, and we've come to find out that the restorer shorted out the either:

  • the in tank fuel sender
  • or the gas gauge
  • or both...

 

First question:

  • Is the Dashboard Fuel Indication Gauge from a 63, 64, 65 "UNIVERSAL" or did GM make a different one for each model or?  

 

First Observation:

  • I'm told that the factory equipped A/C Rives have two (2) fuel lines going to the fuel tank sender unit - is this the case?

 

Thanks in advance for your help as we try to figure this out!

 

fast_dave

 

Edited by fast_dave (see edit history)

Share this post


Link to post
Share on other sites
RivNut    956

There's also a difference in the the fuel sending units in the ohms used in the resistor between the years.

Share this post


Link to post
Share on other sites
petelempert    42

Check out ROA forum information from May 2011 and you'll find info on this topic. Memory here is a little foggy, but here goes: All GM prior to 65 used sender units with resistance of 0-30. In 65 they switched to 0-90. Obviously the gauges changed at the same time to reflect the resistance. You might be using the wrong unit. My guess is you've got a ground problem. On 63-4 the ground is actually the tank straps. Not sure on a 65, but I bet it's the same. You could test this theory by creating a new ground off the sender and running it to a clean spot on the frame. PRL

 

Share this post


Link to post
Share on other sites
60FlatTop    1,899

If it runs out of gas when the gauge reads 1/4 tank it is the same as mine has always been. I only had it happen once.

Bernie

Share this post


Link to post
Share on other sites
jsgun    29

Is there an issue with removing the vent line, and going to a vented cap?

Share this post


Link to post
Share on other sites
RivNut    956

The tank is vented. Look for a piece of tubing that goes around the top of the filler neck as you look at it.  The return fuel line is there so vapors can be returned to the tank rather than building up in the main line and causing vapor lock.

Share this post


Link to post
Share on other sites
alini    120

The sending units that are available typically from eBay are not manufactured well.  They fit poorly and even with the correct ohms you need to adjust the way the float sits in the tank.   I put mine in and it never read full. It would show about 7/8 full and when I was near E I still had about 5 gallons left.  So the float would sit at the top of the tank but the way the contacts were in the actual sending unit it wasn't maxed out.  

Share this post


Link to post
Share on other sites
RivNut    956

before doing anything drastic, go back to what Pete said in post #4 about grounds. Strap a dedicated ground wire to a cleaned section of the gas line near the tank. Run that to a screw in some fresh metal.  See what, if any, improvements that may give you.   When I dropped the tank on my '64, I added a ground wire to one of the sending unit hold down screws and drilled a small hole into the floor pan to which I connected the other end of the wire - made a world of difference.

 

Ed

Share this post


Link to post
Share on other sites
Rivdrivn    85
8 hours ago, alini said:

The sending units that are available typically from eBay are not manufactured well.  They fit poorly and even with the correct ohms you need to adjust the way the float sits in the tank.   I put mine in and it never read full. It would show about 7/8 full and when I was near E I still had about 5 gallons left.  So the float would sit at the top of the tank but the way the contacts were in the actual sending unit it wasn't maxed out.  

Chris,

I had the same experience. The new sending units look great until you try to get them to fit. And now a full tank reads 3/4 on the gauge. It's reading 1/4 now but I didn't know where empty is. So, thanks.

Share this post


Link to post
Share on other sites
PWB    203
6 minutes ago, Rivdrivn said:

Chris,

I had the same experience. The new sending units look great until you try to get them to fit. And now a full tank reads 3/4 on the gauge. It's reading 1/4 now but I didn't know where empty is. So, thanks.

What fails on the sending units?

Share this post


Link to post
Share on other sites
60FlatTop    1,899

I have been driving GM cars all my life, lots of them,and the only ones I owned that had what I would call an accurate fuel gauge are the '03 and '05 pickups.

 

The '60's and '70's cars had a needle that floated all over the place, maybe within 50% of the level. The '94 Impala stays at full for the first 150 miles, then drops like a rock. (They make an aftermarket resistor for that to correct it.) Just keep it full and don't worry. I fill the truck when the trip meter hits 200 and the old cars on Sunday. My Wife's Tahoe gets down to 3/4 in about a month or six weeks and we fill that.

 

Right now my truck is at 3/4 and the '86 convertible is empty because I put new high pressure lines at the sending unit. The rest of the stuff is full.

 

GM builds more accurate odometers than fuel gauges. On a trip with the old cars I would stop and fill around 150 miles. Good for an old guy, fill the car, drain the bladder.

 

Bernie

Share this post


Link to post
Share on other sites
Rivdrivn    85
12 minutes ago, PWB said:

What fails on the sending units?

Works fine, just takes a hammer to make it fit and then it doesn't read correctly. I tried all the different sources; its always the same manufacturer. So, the original poster for this thread should ask if his was replaced as well.

IMG_3272.JPG

Share this post


Link to post
Share on other sites
alini    120

Mine wasnt that far off on fitment, I was able to tweak the angle of the tube enough to get the holes to line up.  But the armature needs to be adjusted to get it more accurate.  With the tank out and the new sending unit in place, you can see the float for the sending unit.  I would using a yard stick or some long rod push the float as high as you can and check the resistance.  Then try to get it as low as possible and see where it hits zero (if at all)  tweak the rod the float sits on until you get a happy medium.....then bolt it all back together and hang the tank

 

Had I know this before I put it back together I would have spent the time  but once it was back togehter and I saw the flaw I decided to live with it....especially knowing everyone else had the same issue

Share this post


Link to post
Share on other sites
telriv    44

"64 & earlier had 45ohms resistance. '65 up had 90ohms resistance. I've done quite a few '63'65 Rivs. & they ALL had a separate ground wire from the factory.

Share this post


Link to post
Share on other sites
fast_dave    10

Thanks for ALL of the replies, guys! LOTS of great info!!!

 

Looks like I'll have my bro-in-law start by applying the K.I.S.S. principle, and start by checking for any obvious wire disconnection at the Tank Fuel Sending Unit.

 

Beyond that, going towards "step 2" - allow me to throw this question into the ring:

 

Is there an gas gauge/fuel sender fuse or circuit that can get "shorted out" or "fried" when doing a frame off restoration ???

 

I know the electrics in Riv's are it's Achilles Heel, and during a restoration moving around wiring harness' that have been in place 51  years can cause issues...

 

 

Share this post


Link to post
Share on other sites
1965rivgs    49
6 hours ago, fast_dave said:

Thanks for ALL of the replies, guys! LOTS of great info!!!

 

Looks like I'll have my bro-in-law start by applying the K.I.S.S. principle, and start by checking for any obvious wire disconnection at the Tank Fuel Sending Unit.

 

Beyond that, going towards "step 2" - allow me to throw this question into the ring:

 

Is there an gas gauge/fuel sender fuse or circuit that can get "shorted out" or "fried" when doing a frame off restoration ???

 

I know the electrics in Riv's are it's Achilles Heel, and during a restoration moving around wiring harness' that have been in place 51  years can cause issues...

 

 

See post #5

  Tom

Share this post


Link to post
Share on other sites
alini    120

The gauge itself has three connections. A power from the circuit card a ground thru the circuit card and the wire to the sending unit.  You can disconnect the sending unit as a point behind the license plate and ground it.  The gauge should move.  With it the wire disconnected the gauge should read full with it grounded it goes to E. if it swings at all the gauge is right it's the sending unit that's bad

Share this post


Link to post
Share on other sites
fast_dave    10

OK - the firm in Sweden that did the frame-off restoration installed the battery cables onto the wrong battery posts...

 

Positive to Negtive, and Negative to Positive...

 

I'm told that somehow the car started with this issue, BUT major electrical issues followed - this being one of them.

 

Apparently two auto electrical shops in Sweden have rewired the car, but this is an outstanding issue.

 

I do not know if the 2 electrical shops have PROPERLY tested the fuel gauge and tank sending gauge, OR are just throwing their hands up and thinking that replacement parts should be thrown at the problem.

 

From your posts I understand that these parts weren't standardized (63, 64, 65) and I'm just here trying to prevent my bro-in-law throwing parts & money at it. 

 

Edited by fast_dave (see edit history)

Share this post


Link to post
Share on other sites
fast_dave    10
8 hours ago, alini said:

The gauge itself has three connections. A power from the circuit card a ground thru the circuit card and the wire to the sending unit.  You can disconnect the sending unit as a point behind the license plate and ground it.  The gauge should move.  With it the wire disconnected the gauge should read full with it grounded it goes to E. if it swings at all the gauge is right it's the sending unit that's bad

 

My bad - I'm having a little trouble understanding this, could you please clarify ?!

Edited by fast_dave (see edit history)

Share this post


Link to post
Share on other sites
KongaMan    125
23 minutes ago, fast_dave said:

OK - the firm in Sweden that did the frame-off restoration installed the battery cables onto the wrong battery posts...

 

Positive to Negtive, and Negative to Positive...

 

I'm told that somehow the car started with this issue, BUT major electrical issues followed - this being one of them.

 

What is "this"?  You still haven't told us specifically what the problems are.  Does it not register full?  Does it not register empty?  Does it not move?  Does it bounce around?

 

Diagnosis is a lot easier when you know the symptoms...

Share this post


Link to post
Share on other sites
Seafoam65    158

                The car could never have started with the battery cables reversed, but it  most certainly would have fried everything not protected by a fuse instantly the moment the last battery cable was attached to the battery. If they told you they started it with the cables reversed

on the battery they are lying to you. 

Edited by Seafoam65 (see edit history)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this