Pennock's Fiero Forum
  Technical Discussion & Questions
  What is more common to have failed when the gas gauge quits working?

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
What is more common to have failed when the gas gauge quits working? by JohnWPB
Started on: 04-04-2014 02:18 PM
Replies: 7 (211 views)
Last post by: phonedawgz on 04-04-2014 09:34 PM
JohnWPB
Member
Posts: 5154
From: West Palm Beach, Florida
Registered: May 2009


Feedback score:    (21)
Leave feedback





Total ratings: 143
Rate this member

Report this Post04-04-2014 02:18 PM Click Here to See the Profile for JohnWPBClick Here to visit JohnWPB's HomePageSend a Private Message to JohnWPBEdit/Delete MessageReply w/QuoteDirect Link to This Post
The gas gauge in my 86 GT is not working. It shows full almost all the time, and often just starts spazzing out and jumping around like I am driving around in the Bermuda Triangle!

What is the most common to fail, if there is one that is more like to fail than the other; The gas gauge itself, or the sending unit in the tank? Is there an easy way for me to check with a multimeter at the dash? I say easy way, as I am no good with electrical, and would need a step by step.

From all of my phone calls, no parts stores from anything local, national chains, as well as Rock Auto carries the sending unit. I called the Fiero Store, and they do carry the sending unit, and it is a bit steep at $220. I want to make sure that is the problem before I go dropping 2 bills, and it winds up being wasted cash.

.

.




High Quality Fiero Reproduction Stickers are Available in THIS THREAD IN THE MALL.

[This message has been edited by JohnWPB (edited 04-04-2014).]

IP: Logged
PFF
System Bot
Gall757
Member
Posts: 10622
From: Holland, MI
Registered: Jun 2010


Feedback score: N/A
Leave feedback





Total ratings: 88
Rate this member

Report this Post04-04-2014 02:52 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
If it reads 'Full' there is a break in the circuit....(infinite resistance). It can be a broken wire, but most likely the windings on the sender are losing contact. Many have been successfully rebuilt with no need for a new unit. If your gauge needle dances around sometimes, that means that the gauge is working. You might get lucky and fix the sender this way:

http://www.fiero.nl/forum/Forum2/HTML/123226.html
IP: Logged
phonedawgz
Member
Posts: 17009
From: Green Bay, WI USA
Registered: Dec 2009


Feedback score:    (23)
Leave feedback





Total ratings: 290
Rate this member

Report this Post04-04-2014 02:54 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
The tank wiring plugs into the body wiring in a connector in the engine compartment and the connector is located about directly behind the passengers left elbow. It is a three wire connector - Tan/White - Pink - Black or Black/White. Unplug it. Turn the key to on. With a paperclip short the Pink wire to the Black on the body side connector. If the gas gauge goes from to empty the sender is your problem.

Most likely your sender is the problem.

Best way to fix it and at a reasonable price if it is the sender - http://www.fiero.nl/forum/A...090219-2-078597.html

Zero the gauge at empty.

Dropping the tank is a pita. Dropping the tank more than once to fix this is foolish.

[This message has been edited by phonedawgz (edited 04-04-2014).]

IP: Logged
JohnWPB
Member
Posts: 5154
From: West Palm Beach, Florida
Registered: May 2009


Feedback score:    (21)
Leave feedback





Total ratings: 143
Rate this member

Report this Post04-04-2014 04:33 PM Click Here to See the Profile for JohnWPBClick Here to visit JohnWPB's HomePageSend a Private Message to JohnWPBEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have a fuel leak (Happened on the way to the Daytona Show ) and will more than likely be dropping the tank anyways. Being I am dropping the tank, what should I look for / clean to try to fix the sending unit? I read the one thread at the link above about running cleaner through the system, and it fixing that particular problem. This being the case, I should be able to clean "it" manually. What exactly should I be trying to clean? I mean other than the obvious gunk that I will probably find on the float and such.

IP: Logged
Gall757
Member
Posts: 10622
From: Holland, MI
Registered: Jun 2010


Feedback score: N/A
Leave feedback





Total ratings: 88
Rate this member

Report this Post04-04-2014 04:47 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
I had a great thread for you, but the pictures are now GONE. The text can be of some assistance I guess.....but it's the poster-child for why we should use PIP!!

http://www.fiero.nl/forum/Forum2/HTML/092117.html
IP: Logged
JohnWPB
Member
Posts: 5154
From: West Palm Beach, Florida
Registered: May 2009


Feedback score:    (21)
Leave feedback





Total ratings: 143
Rate this member

Report this Post04-04-2014 05:29 PM Click Here to See the Profile for JohnWPBClick Here to visit JohnWPB's HomePageSend a Private Message to JohnWPBEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for the link, I will try to make the best of the text.

[RANT] I get SOOOoo sick of people saying " I don't use PFF image poster, and NEVER have a problem". As you said that thread is the poster child for using it. I get so sick of finding a great thread and all of the images are gone. You will NEVER find a post by me with broken images, as I always us PFF image poster for that very reason [/RANT]
IP: Logged
notaguru
Member
Posts: 232
From: San Diego, CA
Registered: Dec 2013


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-04-2014 09:10 PM Click Here to See the Profile for notaguruClick Here to visit notaguru's HomePageClick Here to Email notaguruSend a Private Message to notaguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
Using the procedure above, you will probably discover that the poorly-engineered GM sender unit is the issue. It's very fragile - a terrible design, probably by the same engineer that did the dew wipes.

I bought a "universal" sender on eBay for $22 including shipping, and discarded everything but the swinging arm and the base holding the resistor coil. That base mounted nicely on the original support with nylon (fuel-proof) cable ties, and I bent the arm so it would have the same swing as the original. Resistance is 90 ohms full, close to zero empty. Works perfectly and is very stable. It's a robust solution that might outlive the rest of the car.

The biggest task is R&R of the fuel tank. While it's out (and empty), you might remove all the crap that will have accumulated, and have the tank cleaned by a radiator repair shop. Don't be surprised if an internal baffle has cracked or broken (just remove the broken pieces - it'll work ok). Fuel pumps are cheap compared to the work involved, so if you still have the original it might be a good idea to replace it and the screen.

One other point. The wiring to the fuel pump might need freshening to ensure that there are no high-resistance connectors in the circuit. Just pulling, cleaning, and replacing the connections will sometimes make a measurable difference in the voltage detected at the pump (when operating).

Before reassembling, take a close look at the rubber lines that connect the metal lines from the fuel tank to the car.

And while the tank is down, you have a chance to apply rust reformer or other treatment to the cavity it normally blocks.

Good luck!

[This message has been edited by notaguru (edited 04-04-2014).]

IP: Logged
phonedawgz
Member
Posts: 17009
From: Green Bay, WI USA
Registered: Dec 2009


Feedback score:    (23)
Leave feedback





Total ratings: 290
Rate this member

Report this Post04-04-2014 09:34 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock