fast_dave Posted April 14, 2017 Share Posted April 14, 2017 (edited) 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 April 14, 2017 by fast_dave (see edit history) Link to comment Share on other sites More sharing options...
Dales90 Posted April 14, 2017 Share Posted April 14, 2017 By my previous experience, yes, two lines for the sending unit. Fuel feed and vapor lock breather. Link to comment Share on other sites More sharing options...
RivNut Posted April 14, 2017 Share Posted April 14, 2017 There's also a difference in the the fuel sending units in the ohms used in the resistor between the years. Link to comment Share on other sites More sharing options...
petelempert Posted April 14, 2017 Share Posted April 14, 2017 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 Link to comment Share on other sites More sharing options...
1965rivgs Posted April 14, 2017 Share Posted April 14, 2017 What is the problem? Tom Link to comment Share on other sites More sharing options...
60FlatTop Posted April 14, 2017 Share Posted April 14, 2017 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 Link to comment Share on other sites More sharing options...
jsgun Posted April 15, 2017 Share Posted April 15, 2017 Is there an issue with removing the vent line, and going to a vented cap? Link to comment Share on other sites More sharing options...
RivNut Posted April 15, 2017 Share Posted April 15, 2017 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. Link to comment Share on other sites More sharing options...
alini Posted April 15, 2017 Share Posted April 15, 2017 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. Link to comment Share on other sites More sharing options...
RivNut Posted April 15, 2017 Share Posted April 15, 2017 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 Link to comment Share on other sites More sharing options...
Rivdrivn Posted April 15, 2017 Share Posted April 15, 2017 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. Link to comment Share on other sites More sharing options...
PWB Posted April 15, 2017 Share Posted April 15, 2017 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? Link to comment Share on other sites More sharing options...
60FlatTop Posted April 15, 2017 Share Posted April 15, 2017 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 1 Link to comment Share on other sites More sharing options...
Rivdrivn Posted April 15, 2017 Share Posted April 15, 2017 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. Link to comment Share on other sites More sharing options...
alini Posted April 15, 2017 Share Posted April 15, 2017 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 Link to comment Share on other sites More sharing options...
jsgun Posted April 15, 2017 Share Posted April 15, 2017 Good to know about that sender, I almost bought one. Link to comment Share on other sites More sharing options...
telriv Posted April 15, 2017 Share Posted April 15, 2017 "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. Link to comment Share on other sites More sharing options...
fast_dave Posted April 15, 2017 Author Share Posted April 15, 2017 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... Link to comment Share on other sites More sharing options...
1965rivgs Posted April 16, 2017 Share Posted April 16, 2017 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 Link to comment Share on other sites More sharing options...
alini Posted April 16, 2017 Share Posted April 16, 2017 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 Link to comment Share on other sites More sharing options...
KongaMan Posted April 16, 2017 Share Posted April 16, 2017 On April 14, 2017 at 3:05 PM, 1965rivgs said: What is the problem? That would seem to be a pertinent question. Link to comment Share on other sites More sharing options...
fast_dave Posted April 17, 2017 Author Share Posted April 17, 2017 (edited) 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 April 17, 2017 by fast_dave (see edit history) Link to comment Share on other sites More sharing options...
fast_dave Posted April 17, 2017 Author Share Posted April 17, 2017 (edited) 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 April 17, 2017 by fast_dave (see edit history) Link to comment Share on other sites More sharing options...
KongaMan Posted April 17, 2017 Share Posted April 17, 2017 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... Link to comment Share on other sites More sharing options...
Seafoam65 Posted April 17, 2017 Share Posted April 17, 2017 (edited) 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 April 17, 2017 by Seafoam65 (see edit history) Link to comment Share on other sites More sharing options...
KongaMan Posted April 17, 2017 Share Posted April 17, 2017 48 minutes ago, Seafoam65 said: The car could never have started with the battery cables reversed... Sure it would -- you'd just have to drop it in R to move forward. Link to comment Share on other sites More sharing options...
RivNut Posted April 17, 2017 Share Posted April 17, 2017 Plus the engine would bring rotating backwards so the generator would discharge the battery and the a/c would put out hot moist air. You'd have to step on the brake to move the car and use the accelerator to stop it. Everything you'd see in the mirror would be in front of you. Hmmmmm? What else? 1 Link to comment Share on other sites More sharing options...
fast_dave Posted April 17, 2017 Author Share Posted April 17, 2017 (edited) 22 hours ago, KongaMan said: 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... I agree - I'm trying to get the whole story as well. My bro-in-law thinks that all this can be solved by throwing parts at it. From reading what you guys have written, I can clearly see that it's not that simple, and know that if I blindly get involved, I will spend a LOT of time at the post office sending parts over and over and over. Thanks for bearing with me - I'm pulling teeth in Sweden (over the internet) trying to establish what the gas gauge is "indicating" I will keep you all advise and thank ALL of you heartily for ALL of your help. Special shout-out to Alini and KongaMan Sincerely, fast_dave Edited April 17, 2017 by fast_dave (see edit history) Link to comment Share on other sites More sharing options...
Recommended Posts
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 accountSign in
Already have an account? Sign in here.
Sign In Now