R32 GTR fuel gauge not working despite fixing fuel level sender

[XoRoKu]

My fuel level sender was shot so I decided to fix it properly with repair kit from FPG.
Now I can read resistance and confirm that it changes with movement using the method in the service manual (page EN-258).

However, the fuel gauge on the cluster still refuses to move.
I need help to figure out next steps to troubleshoot the issue as I was really hoping fixing the sender would do it but it seems that I have multiple issues here.

By the way I haven't started the engine since fixing. My assumption (and going from memory from when the gauge worked) is that the needle should move when the key is in the ON position without having to start the engine. Please correct me if that's wrong and I'm just trying to fix an non existent issue because I was too dumb to just start the engine...

Thanks for the help!

[TurboTapin]

10 minutes ago, XoRoKu said:

My fuel level sender was shot so I decided to fix it properly with repair kit from FPG.
Now I can read resistance and confirm that it changes with movement using the method in the service manual (page EN-258).

However, the fuel gauge on the cluster still refuses to move.
I need help to figure out next steps to troubleshoot the issue as I was really hoping fixing the sender would do it but it seems that I have multiple issues here.

By the way I haven't started the engine since fixing. My assumption (and going from memory from when the gauge worked) is that the needle should move when the key is in the ON position without having to start the engine. Please correct me if that's wrong and I'm just trying to fix an non existent issue because I was too dumb to just start the engine...

Thanks for the help!

It should work without the car running. Confirm you see roughly the same resistance from the level wires at the back of the cluster. If they're good, your cluster is fubar. If not, start tracing that wire back. 

[XoRoKu]

Thanks, I checked from the back of the cluster and no reading there.

I undid the connector and plugged in the wires directly to start from where I'm getting a reading: https://imgur.com/a/W8JI6Yr

Weirdly enough when I tried to get a reading from the crimps that connect to the fuel pump assembly, I got nothing.

Not sure what's my next step as I have admittedly limited knowledge with electricity. 

[joshuaho96]

5 hours ago, XoRoKu said:

Thanks, I checked from the back of the cluster and no reading there.

I undid the connector and plugged in the wires directly to start from where I'm getting a reading: https://imgur.com/a/W8JI6Yr

Weirdly enough when I tried to get a reading from the crimps that connect to the fuel pump assembly, I got nothing.

Not sure what's my next step as I have admittedly limited knowledge with electricity. 

If you're using resistance mode on the multimeter of course plugging it in with a live battery won't yield a useful reading. Either disconnect the 12V while you do resistance testing or look up what the voltage should be for your current level and chase it back to the gauge cluster to isolate where the failure happens.

[GTSBoy]

Yeah, see....when you have this

1 hour ago, joshuaho96 said:

If you're using resistance mode on the multimeter of course plugging it in with a live battery won't yield a useful reading. Either disconnect the 12V while you do resistance testing or look up what the voltage should be for your current level and chase it back to the gauge cluster to isolate where the failure happens.

vs. this

7 hours ago, XoRoKu said:

I have admittedly limited knowledge with electricity.

Then you get me recommending to just take it to an auto-electrician to save the possibility of setting it on fire.

[XoRoKu]

Fair enough, I'm out of my depth with chasing electrical issues.

I measured the resistance with battery disconnected. and got 25 directly on the fuel pump assembly and 17 on the wires connected to the fuel pump assembly and the same reading from the back of the cluster. I would bring it to someone who specializes in electrical issues but at this point it looks like the issue is at the cluster so not sure what more they could troubleshoot.

Anything I can try with the cluster or nothing to do but replace it?

[joshuaho96]

1 hour ago, XoRoKu said:

Fair enough, I'm out of my depth with chasing electrical issues.

I measured the resistance with battery disconnected. and got 25 directly on the fuel pump assembly and 17 on the wires connected to the fuel pump assembly and the same reading from the back of the cluster. I would bring it to someone who specializes in electrical issues but at this point it looks like the issue is at the cluster so not sure what more they could troubleshoot.

Anything I can try with the cluster or nothing to do but replace it?

Check for blown capacitors, burned traces, cold/cracked solder joints, corrosion, etc. You can try sending the cluster out to a shop that specializes in electronics repair.

[GTSBoy]

5 hours ago, XoRoKu said:

so not sure what more they could troubleshoot.

I can think of two places in my city of <1.5million population that specialise in automotive instrument repairs.Unless you're out in the wilds of Quebec, you have 3 major Canadian and 3 major US cities within the same distance as the single nearest city to mine. Surely there is somewhere you could send it.

[XoRoKu]

Opened up the cluster to inspect the gauge itself for signs of damage and it looks good.

Got curious since that needle doesn't go back to a "neutral" position by itself (it stays in the same position when ignition is off. so I manually moved it to 1/2. Connected it back, turned on the ignition and the needle started moving up!

Not sure what's up with that but before that the needle was way down below empty like fully south west. There's always a chance that the needle moved slightly the first time I tried and I didn't notice because of how slowly it moves and how far it was from the markings.

I don't know if the current needle position is accurate so I'll fill it up and see where that brings it. I guess I'll try to adjust it manually if it doesn't get to F. Looks like the needle position is relative and not absolute?

Thanks all for your help and patience!

[soviet_merlin]

21 hours ago, XoRoKu said:

Got curious since that needle doesn't go back to a "neutral" position by itself (it stays in the same position when ignition is off.

That at least is a feature. So you can see the fuel level even when the car is turned off. I presume the fuel level sensing is fairly similar between the different generations. Here's what the Stagea user manual has to say about it:

 

Don't know about your other points but I'd be curious to know as well. I'm kind of waiting for @Duncan to chime in because he has been doing a fair bit of fuel system related stuff recently. Including fuel level sensor finagling in his build thread.

[GTSBoy]

R32 fuel gauge definitely stays at the current reading when turned off. It will not show a new reading (ie if it was low and you just filled up) until it is turned on, at which point it should sweep from empty to full in only a few seconds.

[Duncan]

BTW, level up linking and @-ing, thanks David

I actually don't have much to add, except that I have seen electrical gauges "off the scale" due to some sort of mechanical issue that work properly again after freeing up....sounds like that might be what happened here...