Pontiac Street Performance
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password

 All Forums
 Pontiac Performance
 Tempest / Lemans / GTOs
 Gas gauge problem
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

ponchopilot
Tribal Scout

USA
7 Posts

Posted - 30 Jul 2016 :  2:37:06 PM  Show Profile  Reply with Quote
My gas gauge has always worked on my 71 t37. I filled the tank a few weeks ago and it's been pegged over the full mark ever since. Is this just a wiring problem? Or is it in the gauge/sending unit? Any feedback would be most appreciated, thanks.

"95% of chevys are still on the road... the other 5% made it home."

cortcomp
Coyote

USA
5338 Posts

Posted - 30 Jul 2016 :  4:32:00 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I forget if no connection to the sending unit is stuck open or closed on those. If you can get to it, i'd disconnect the wire and see if it moves. If not, i'd touch the wire to a ground and see if it moves (key on of course.) If not, i'd be leaning towards wiring/gauge. Most likely however, it's the sending unit. And if you're dropping the tank to get the wire off, well, you're there already.
Go to Top of Page

ponchopilot
Tribal Scout

USA
7 Posts

Posted - 31 Jul 2016 :  2:07:23 PM  Show Profile  Reply with Quote
Thanks for the advice, I'll try to go take a look at it later today and see if I can get it to move.

"95% of chevys are still on the road... the other 5% made it home."
Go to Top of Page

GtoGuy32
Cochise

USA
842 Posts

Posted - 31 Jul 2016 :  11:11:35 PM  Show Profile  Reply with Quote
I had this issue about 15 years ago and it turned out to be the sending unit.

All wires were good.

The sending unit is a potentiometer (variable resistor). You can hook a multimeter up to it and put it on resistance measurement. If the resistance changes when you move the lever and I think it must go to 90 ohms (cant remember for sure), then the sending unit is okay.

Good luck
Go to Top of Page

frankie
Buffalo

USA
62 Posts

Posted - 17 Aug 2016 :  8:08:44 PM  Show Profile  Reply with Quote
yes the same thing happened to me too and it was the sending unit
Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 21 Dec 2016 :  4:52:01 PM  Show Profile  Reply with Quote
I'm glad someone asked this question and others answered it. I've had my Lemans for 25 years and the gas gauge worked for the first 20. Now it works sometimes. When it doesn't work it is pegged full. When it works it works great. But it usually works until it gets to empty then it pegs full - which is about the worst time for a gas gauge to say full.

As it happens I've stranded myself several times over the past couple years due to running out of gas. I've fiddled with every possible wire and have concluded it's the sending unit. This is consistent with some of the answers above saying it's the sending unit.

But do I really want to fix it? The sometimes-working gas gauge adds just that extra bit of excitement to my day. I've been writing down my fuel consumption for 25 years so I just watch my odometer and check my book. I suppose when I have the trunk floors repaired the body-man will have to drop my gas tank. That's when I'll replace the gauge. I will no doubt afterwards ask myself why I never fixed it sooner.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page

cortcomp
Coyote

USA
5338 Posts

Posted - 21 Dec 2016 :  8:36:45 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
These aren't generally that bad to fix, especially if you run it low on gas. I generally put the axle on jack stands, disconnect hosts, and put floor jack there. remove strap bolts and drop it, swap the sending unit out, reverse. Usually like 20 min. Some cars i can even leave the hoses hooked up if there's enough slack in them to just tilt the tank down, and it's empty.
Go to Top of Page

Lee
Sitting Bull

101 Posts

Posted - 22 Dec 2016 :  12:06:22 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
My fairly recently acquired '73 'bird had the same issue - worked at times, read pegged-out full at others. About $40 for a new sending unit from eBay, maybe an hour of work (taking my time), and now works fine ALL the time!

Do it :-)

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 22 Dec 2016 :  5:01:28 PM  Show Profile  Reply with Quote
but what about the thrill of coasting a half mile to a stop on a busy highway, wondering if I'll make it to the next exit ramp?

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page

NOTROD
Buffalo

USA
64 Posts

Posted - 25 Dec 2016 :  11:09:28 PM  Show Profile  Reply with Quote
Same thing happened to me this fall...reading full all the time. It was a poor connection on the sending unit. Unfortunately it was internal so I had to drop the tank and pull it out. Not bad though, they're pretty simple units. Start to finish, it probably took about 2 hours.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Pontiac Street Performance © 2006-2017 Go To Top Of Page
This page was generated in 0.11 seconds. This Site Sponsored By:
Powered By: Snitz Forums 2000 Version 3.4.05