On a few occasions, my fuel gauge has come to life but essentially, it's non-functional. What are the odds it's the in tank sensor and do I have to drop the tank to replace it? It's a '93 Turbo wagon. TD

 

Less familiar with the 900 series car. However, I worked on a 700 series that had a fuel gauge with intermittent problems. Turns out the printed circuit on the back was burning up. I'd check that, as removing your instrument cluster is likely easier than getting to the in tank cluster. I can't help you much removing it--I know by the time the 900 series had come along, they had changed the cluster a bit, but I'm sure other people on here know what to do.

 

you don't drop the tank to access the tank sender/pump assemblys, its accessed via a plate behind the back seat, under the floor panel (if its a wagon) or trunk carpet (sedan).

but yeah, I'd start at the instrument cluster.

 

Definitely start with the cluster, the circuit board in back should have be refloated. This may be your issue rather than the tank sender. It could also be the gauge itself, so one of three possibilities. There's a testing procedure for the tank sender.
To test the unit disconnect the negative battery cable. Disconnect the fuel gauge sending unit connector and measure the resistance, with an ohmmeter, between the grey/white and brown wires. Resistance should be 0-280 ohms on a 15 gallon tank and 0-367.5 ohms on a 21 gallon tank. If resistance is not as specified the unit is defective. On some models the grey/white wire may have been replaced with an orange/white.

 

Thanks for all the help guys. I had looked for an access plate like in the older Volvos but I guess didn't look hard enough. Is it a chore getting to the back of the instrument cluster? Like something that will give a 68 yr old guy a crick in his neck for a week? TD

 

the instrument panel pulls straight out of the dashboard, but you need to release some catches by inserting a long thin screwdriver into the slot on each side just in front of the plastic lens.

if you have a sedan, remove the trunk carpet, there shoudl be a black panel about 8" square screwed to the floor just behind the left rear seat. If its a wagon, fold the rear seats down, lift up that hinged flap behind the seat that covers the hinge, and there's a couple screws, remove them, and that flap plus the floor panel behind it lifts out, exposing the access plate.

Volvo Fuel Tank Pump/Sender Replacement for accessing the in-tank fuel pump and fuel level sender (740 and 940 all same, but there's different pumps for Regina vs Bosch EFI).

 

Thanks Pierce. I found the access plate for the tank and the slots to release the dash cluster. I can feel the spring releases inside the slots on the cluster as I insert little screw drivers, but I'm unsure of what to pull on to get the assembly to slide out. I don't want to break any of the little plastic bits as I pull on it. TD

 

the whole instrument panel, INCLUDING the metal frame pulls out. while pushing the two tabs in, I use additional fingers on either side of the metal frame to slide it towards you. once its moved 1/2" or so, you don't need to hold the clips anymore.

 

So I've gotten the black outer piece off exposing the aluminum frame, removed the two screws & clips so I can move the frame & cluster outward but it doesn't want to move very far. I can't see behind the fuel gauge and don't want to pull to hard as I'm sure there are wire harness plugs back there. How far should I be able to move it out & will I have to release some wiring plugs to get at that circuit board behind the gauge?

Also, I found the access plate (right where you said it would be in a wagon) for the tank sender removal is I end up going there. It's sure not intuitive to look there, but hey, "it's a Volvo!" TD

 

once you've unbolted it, the whole thing should remove as a unit, there should be sufficient wire length to get it far enough out to disconnect the couple connectors. if you have a turbo, there's also a vacuum line to the turbo boost gauge, don't try and unplug this from the back of the instrument panel,. instead,. follow the line down into the bowels of the dash, and you'll find a rubber tube splice, disconnect it there (and remember to reconnect it).

 

Baby Steps! I feel like Bill Murray in "What About Bob?" Great Movie!

I managed to get the aluminum frame around the cluster to clear the little eighth inch lip of the dash at the bottom by using a couple thin door panel removers to pry it over. Maybe it's so tight from the dash shrinking from heat over the last 22 yrs? The car came from Texas.

Obviously that turbo vacuum line must be disconnected before one can get the cluster in a position to carefully unplug all those harness plugs. Can you gain access to that vacuum line splice you mentioned by removing the panel under the dash over the brake and access. pedal? TD

 

there was enough turbo vacuum line for me to reach my hand behind the panel, and follow the line down to the fitting, and do a one-hand disconnect by grabbing the line with my little and ring finger, and use my thumb and index finger to push the rubber joiner off. reinstall was the reverse.

I don't remember if I unplugged the electrical connectors before or after the vacuum line.

 

Since I wasn't able to get my hand down to where the coupling in the turbo vacuum line is, I opted for removing the under dash panel (two cam-type screws) and the splice was right in front of me. That was good news. Have all the harness clips removed but the very strange one in the center with a right angle to it was very strange

There is no evidence of breaks or burns on the printed circuit directly behind where the fuel gauge is located. Lev mentioned the term "Refloated"? What does that mean?

What is the little metal box right above & to the center the cluster from the fuel gauge connections to the circuit board? Is that related to the clock or the fuel gauge? I know the old 140s had some sort of regulator in the fuel gauge circuit on the back of the cluster (half" X 1 & a half") that fastened on with spade connectors.

At this point I'm thinking I've got to look toward the fuel tank. Can I check the resistance of the sender at the cluster or must that be done back at the tank? I reckon I'll change all the bulbs at this point also while I'm in there. TD

 

the 3 (or is it 4?) wire right angle connector is the speed sensor signal from the rear end going into the speedometer.

I would find the pinouts for the fuel gauge connector, and with it unplugged, put an ohm meter across it, and see what the resistance is, then add some gas, like a 5 gallon jerry can full, and read it again, see that its changed the proper amount.

ok, the fuel level sensor is connector C, an 18 pin slanted in-line thing, pin 3 (grey-white) and pin 4 (brown, ground)... per Fuel System: Pumps, Relays, on a 1993 totally empty tank is 130 ohms, 'low gas' LED is 113 ohms, and completely full is around 2 ohms. note those are ohms not KiloOhms.

to test the fuel gauge in the dash, plug it all back in, and unplug the sender, and put a 68 ohm resistor across it instead, switch the key on, you should see around 1/2 tank.

 

Just for clarification: I find the pinouts at the dash cluster connector C (pin 3 (grey-white) and pin 4 (brown, ground), and that will determine that the sender/float assembly is working correctly if resistance drops within the range of 130 and 2 ohms when I add gas.

Then, I re-connect all the wire harness plugs, remove the tank access plate, and there I can unplug the sender wire, bridge the wire to the gauge with the 68 ohm resistor at that plug which will mimic about a half tank for the guage. TD

 

eggzackly

 

Got a reading of 28 ohms with 116 miles off a full tank. Filled the tank and reading dropped to approx 2 ohms, just like you said, so I think I can conclude all is well in the tank. If it ends up being the gauge itself, is it pretty straight forward to replace it? TD

 

I believe a replacement fuel gauge has to be 1993+ as 1992 and earlier used a completely different instrument panel and the pods aren't interchangable, and the fuel senders used a differen resistance scale.

 

Thanks for that critical bit information regarding years to take with me to the parts store or the junk yard!!

There is no obvious point to access the wire going from the sender to the gauge, Do I remove that big adele clamp holding the hose & wire assembly to the tank, or do I crawl under the car to find a disconnect in the wire going from the sender to the dash cluster? TD

 

I think the connectors are over near the antenna on a wagon. remove the popout panels and carpet and stuff.