Author Topic: How to replace your fuel level sensors (Example is MY05 WRX, applies to STI) (Read 9068 times)

GrantC · « **on:** September 23, 2009, 09:04:59 am »

Things you'll need:

shop towels
12mm socket
8mm socket
8mm socket
needle nose pliers
trim tool (make it tons easier)
gas tank that isn't full (makes it cleaner)
beer (if you're showing up at a buddies house to do it)
fuel unit assy 85111AC012 (drivers side level sensor & pickup)
level sensor (m) 42081FE021 (level sensor that goes on passenger side fuel pump assy)

Here's where the access panels are, towards the front of the trunk:

Undo the trim clips & pull back the trunk lining on the passenger side:

So you can un-clip the fuel relay & then start the car till it runs out've fuel pressure:

But there's no way you'll do the rest of this from inside the trunk.

Remove the back seats:
-2 12mm bolts at the bottom of the seat bottom & it lifts out

-4 12mm bolts along the bottom of the seat back and you can press it towards the back of the car to unclip it and lift it out.

Here you can almost see the access panel, you just have to remove those vertical bars & their carpeted trim:
-remove the 4 12mm bolts & the 4 "christmas tree" style trim clips

Now you can easily access the panel:
-undo the 3 philips screws

-unclip the plug & pull off the rubber line (keep the towel ready)
-undo the 6 8mm nuts to remove it.

Here's the old assy (with the sock on the bottom already moved to the new assy):

New (blue

) assy:

Here's the shiny new assy with it's hose hooked up, wires plugged in, and 6 8mm bolts done back up.

Now onto the passenger side & fuel pump assy:
-undo the 4 philips screws holding on the panel

-Unclip the fuel lines (have the rag ready!)
-the one pointed towards the front of the vehicle will almost always spray.
-pull off the rubber hoses
-undo wiring
-undo 8(?) 8mm nuts

Here's the fuel pump assy removed from the tank:

Here's the new level sender:

Hrm, looks like this one will involve some soldering (to the fuel temp sensor?)

Don't be an idiot! Remove the level sender (1 phillips screw), and the fuel temp sensor (friction fit) and go do your soldering *far* away from the gas fumes!

The level sensor assembly really is just held on with one (very tight) phillips screw.

-solder the fuel temp sensor to the new level sensor.

Installation is the reverse of removal.

Gas gauge when I arrived there:

Gas gauge afterwards:

Sean · « **Reply #1 on:** September 23, 2009, 09:10:38 am »

Haha nice write up.

Funny that your gauge reads higher after you even lost a bit of fuel.

I'll probably be doing this one sooner than later.

GrantC · « **Reply #2 on:** September 23, 2009, 09:12:32 am »

Quote from: Sean on September 23, 2009, 09:10:38 am

Funny that your gauge reads higher after you even lost a bit of fuel.

I'd be worried if it didn't, since I was trying to fix the issue of the gauge reading too low for the amount of fuel left.

STI_Crazy · « **Reply #3 on:** September 23, 2009, 09:18:30 am »

I recall what a pain it was to remove the sensor from that small hole in WRX4's car. It looks it's pretty much the same process with your car though.

Something you forgot to mention Grant for "things" you need is...what else...Stu

wrex4 · « **Reply #4 on:** September 23, 2009, 09:31:11 am »

Stamos! its all a game of angles ! ha ha
and good write up Grant

Hurricane · « **Reply #5 on:** September 23, 2009, 10:02:47 am »

Quote from: STI_Crazy on September 23, 2009, 09:18:30 am

Something you forgot to mention Grant for "things" you need is...what else...Stu

You beat me to it.

GrantC · « **Reply #6 on:** September 23, 2009, 10:09:06 am »

Quote from: Hurricane on September 23, 2009, 10:02:47 am

Quote from: STI_Crazy on September 23, 2009, 09:18:30 am
Something you forgot to mention Grant for "things" you need is...what else...Stu

You beat me to it.

I thought that was implied by my 8th thing you'll need.

FYI, I'll report back if this fixed it when my fuel light next comes on & I fill up

For now it's still a good writeup if you want to clean them, or if you're curious how to do your fuel pump.

poopeebum · « **Reply #7 on:** September 23, 2009, 12:06:47 pm »

sweet! i'll probably do this sometime sooner or later!

Way-do · « **Reply #8 on:** September 25, 2009, 09:10:50 pm »

Gee, that looks way easier than arguing with Calgary Subaru and allowing them to t-shoot it for 3 days/200km and eventually saying OK, we'll replace the $100 sensor under warranty. I guess I only provided them with 1000+km (two tanks) worth of dash photos and a running fuel consumption for the last 30000km. "Well sir, it's really just an estimate and that's perfectly normal for these cars..." "Yes I know, now fix it!" Easy mistake.

Oh and there is no way to dump fuel pressure at the rails? Must be.

GrantC · « **Reply #9 on:** September 25, 2009, 10:27:42 pm »

Quote from: Way-do on September 25, 2009, 09:10:50 pm

Oh and there is no way to dump fuel pressure at the rails? Must be.

We unpluged the fuel pump relay & ran the car till it stalled... there was still fuel pressure...

Way-do · « **Reply #10 on:** September 26, 2009, 08:27:02 am »

I see that, but there must be a way, usually a service port for testing pressure, dumping pressure and so forth in engine bay. I'll post when I find it. Keeps a bit of the fuel stench out of the cabin.

I'll also point out that it is good practice to ground the chassis. Big long wire connected to any bare metal part and grounded to electrical box/conduit in the garage. Now that I think of it it's probably hard to find a good ground in a residential garage.

And it looks like you got away without new gaskets. I never start a job without new gaskets on hand. If you get lucky and don't use them you can always return them. I'll add a part # later.

WD

LilDrunkenSmurf · « **Reply #11 on:** October 20, 2009, 01:40:52 pm »

Quote from: GrantC on September 23, 2009, 10:09:06 am

Quote from: Hurricane on September 23, 2009, 10:02:47 am
Quote from: STI_Crazy on September 23, 2009, 09:18:30 am
Something you forgot to mention Grant for "things" you need is...what else...Stu

You beat me to it.

I thought that was implied by my 8th thing you'll need.

FYI, I'll report back if this fixed it when my fuel light next comes on & I fill up

For now it's still a good writeup if you want to clean them, or if you're curious how to do your fuel pump.

*cough*

GrantC · « **Reply #12 on:** October 20, 2009, 01:47:06 pm »

Because of auto-x I wasn't filling my tank up to the brim, so I had no way of being sure if the light was coming on at the correct time.

Now that auto-x (and trackdays, "grrr") are over I *have* been filling it till it clicks. And it seems that the light is coming on with ~10L left.

I have filled up without the light coming on and put in ~48L (~12L left) and I have filled up after the light has come on and have put in 50+L.

For the moment, I am considering it "fixed"

trevoroni · « **Reply #13 on:** October 20, 2009, 05:21:17 pm »

Thankfully just cleaning my sensors has still solved the problem for me, it's been about 6 months I'd say and the problem hasn't came back as of yet.
I get about 45L before the light comes to the first click.

**Edit:
How much did the new sensors cost if you don't mind me asking?

GrantC · « **Reply #14 on:** October 20, 2009, 05:41:13 pm »

Quote from: trevoroni on October 20, 2009, 05:21:17 pm

How much did the new sensors cost if you don't mind me asking?

~$135 all in.

Part number	Part Description	Quantity	Price	Total
85111AC012	Fuel system, Fuel system components, Meter, Fuel level, Fuel level	1	$51.20	$51.20
42081FE020	Fuel system,Fuel system components, Level sensor, 2.0 liter, 2.0 liter	1	$57.38	$57.38
			Sub Total	$108.58
			Shipping	$27.00
			Total	$135.58

Sean · « **Reply #15 on:** October 20, 2009, 06:12:40 pm »

I believe the tank size is 16.9 gallons from my research, which is 63.9L. Someone correct me if I'm wrong, I just searched and saw 16.9 a couple times and did the conversion assimg US gallons.

LilDrunkenSmurf · « **Reply #16 on:** October 20, 2009, 08:31:39 pm »

Mine's 60L.. Says so right in my manual.

Wally · « **Reply #17 on:** October 20, 2009, 09:04:30 pm »

Quote from: GrantC on October 20, 2009, 01:47:06 pm

Because of auto-x I wasn't filling my tank up to the brim, so I had no way of being sure if the light was coming on at the correct time.

Now that auto-x (and trackdays, "grrr") are over I *have* been filling it till it clicks. And it seems that the light is coming on with ~10L left.

I have filled up without the light coming on and put in ~48L (~12L left) and I have filled up after the light has come on and have put in 50+L.

For the moment, I am considering it "fixed"

I consider the fuel light not coming on with 25L left fixed!

jutes · « **Reply #18 on:** November 01, 2009, 06:45:57 pm »

I think I might be trying this fix soon. The light comes on today with 230km on the tank, I think okay, I've been idling it a little longer than normal and it has been colder out so mileage should suck more than usual. I go to fill up and only get 35L in.

I give the pump a little tap and fuel pours out everywhere, okay, she's full to the brim. Get back inside, start her up and needle only hits 3/4 full.

rs_two_five · « **Reply #19 on:** November 01, 2009, 09:41:38 pm »

great writeup.

I think I'm going to get Saunders to order me in all the parts to change out the level sensors, because if I fill up as soon as the light comes on I can easily fit almost 54 lts in the tank without going past the click. ( 6 lts reserve

), not to mention but if I fill at 1/2 tank I can usually get about 40 lts worth of gas in the tank, so not only is my level out, but so is the warning.

drtran · « **Reply #20 on:** November 05, 2009, 09:41:06 pm »

Quote from: jutes on November 01, 2009, 06:45:57 pm

I think I might be trying this fix soon. The light comes on today with 230km on the tank, I think okay, I've been idling it a little longer than normal and it has been colder out so mileage should suck more than usual. I go to fill up and only get 35L in. I give the pump a little tap and fuel pours out everywhere, okay, she's full to the brim. Get back inside, start her up and needle only hits 3/4 full.

i have the exact same problem, fill the tank and its saying 3/4 full

, abit off topic but are u a member of the cold lake auto club?

Airboy · « **Reply #21 on:** November 05, 2009, 09:50:32 pm »

My fuel gauge is starting to crap out over the last few months. I put in about 40L when the light comes on. Used to be 48-50L when it come on. How much were the parts?

trevoroni · « **Reply #22 on:** November 05, 2009, 10:03:31 pm »

Quote from: Airboy on November 05, 2009, 09:50:32 pm

My fuel gauge is starting to crap out over the last few months. I put in about 40L when the light comes on. Used to be 48-50L when it come on. How much were the parts?

Quote from: GrantC on October 20, 2009, 05:41:13 pm

Quote from: trevoroni on October 20, 2009, 05:21:17 pm
How much did the new sensors cost if you don't mind me asking?

~$135 all in.

It's ok you've been a way awhile and must still have jet lag.

Wally · « **Reply #23 on:** November 06, 2009, 12:05:41 am »

Yeah I'll probably need to purchase a new set in the near future.
I was able to predict how far I could go after the light came on, but with the increased congestion, I'm losing 50km/tank.

Randha17 · « **Reply #24 on:** February 15, 2010, 08:59:45 pm »

I was having this fuel gauge issue for a while too.

I normally only use Husky 94, and I have consistently never gotten to a full reading on my fuel gauge. Normally only get to 3/4 tank when I fill it up and after a few minutes of driving around it might go up another 1/32 or 1/16th if I'm lucky.

I have tossed in 1 bottle of fuel injector cleaner, per tank, for 2 consecutive tanks, in conjunction with switching to Esso.

I actually got a full read on the fuel gauge and the light didn't even come on and I filled 50L!

I would strongly recommend before going to the dealership and picking up new sensors to at least try two tanks of fuel injector cleaner.

Not sure if it was the Esso fuel or the fuel injector cleaner that fixed the sensors.
Either way its fixed!!!