Russ In Vegas

Greetings all...

My '87 928 Instrument cluster... everything appears to be working, with the exception of my gas indicator... Any Ideas or easy tests?

Russ

Mrmerlin

check the contacts at the tank first, you might have to remove the sender. Does the red warning light come on when its close to or on reserve?

Russ In Vegas

Don't know - been keeping the tank full, cause the gauge doesn't work.

jpitman2

Check out web pages of Sharkskin here, he has excellent write up on checking and fixing tank sensor. Basically its a resistance wire wiped by a float, and condensed fuel components can eventually render it non-conducting, or it might break. Lift the rear deck carpet, remove round plastic cover in floor to expose access to the sensor and fuel return line. Check the plug is connected, remove and check for corrosion on pins and plug, correct as needed, check gauge operation again. Check for some volts on one of the pins - 2 are for gauge, 3rd is for low level light.
jp 83 Euro S AT 51k, BTDT

Hilton

+1 on this.. check the connector on top of the sender. Its under the plastic cover in the floor of the rear hatch. Give the contacts a clean and see if it fixes the problem. If not, you might have to remove the sender.


I didn't seat mine properly one day after replacing the fuel pump (I dropped the tank at the same time to replace a vapor hose). Had a scary "Range Warning" while driving home that caused me to pull over immediately to make sure I wasn't spewing fuel everywhere. Luckily it was just the connector, and I still had 3/4 of a tank.

Russ In Vegas

Does this plug come out? It seems that all I can do is take the cover off of it - exposing 3 wires, at the top of the contact -

Russ

ZEUS+

A quick test for wiring and gauge operation:
-Disconnect sending unit and turn ign on, should read empty.
-With test light, check for dim light on one of the terminals. Should be violet and black wire on your car.
-Should be very dim, fuel circuit is low voltage.
-Ground same wire, gauge should peg full.
-If everything tests fine, problem is with sending unit.
Hopefully this can give you some direction

Russ In Vegas

Zeus -

I did that, and I'm getting no power at all to any of the 3 connectors on that plug... Any Suggestions?

Russ

ZEUS+

Do you have wiring diagrams ?

Russ In Vegas

I do - on disc, but haven't a clue on how to read them -

Russ In Vegas

I was hoping it would be a fuse or relay or something easy -

Dennis Wilson

The sender is basically a variable resistor. The brown wire should be a ground and the other two connect to the resistor wires in the sender. You can test it with an ohm meter or test light by connecting to the two wires. If you don't get a circuit one or both of the wires have broken or the float has lost contact with the resistor wires. If you get a circuit, test the wires (with the ignition on) for 12 volts on one of the wires and a circuit to ground on the other. The brown wire should be tested with the ohm meter for a good circuit too ground.

Dennis

jpitman2

When tank is full, resistance should be near zero; empty, should read ~ 80 ohms. Check fuses first. I have found a network cable tracer useful here - connect via an alligator clip to the violet/black, send tone; go to fuse board with pick up wand, see if you can find warble....if not try to follow wire from the sender along the car body until warble stops - there is a break there .
jp 83 Euro S AT 51k

cold_beer839

I'm attempting to fix a gas gauge issue on my GTS. It was reading empty last week so I filled it up. I hadn't driven the car in 3 or 4 weeks so I couldn't remember where the gas level was anyway. After filling it up with only 14 gallons, the gas gauge remained on dead empty, red light on, and CALL RANGE in the message window.

Found this thread and went to check plug on top of tank. Question, how does the damn plug even unplug from the top of the tank?

Mrmerlin

the black square plug pulls straight up no clips or anything else holding it on