Rover 75 1.8T fuel gauge problem

[h4ck]

So as in title i have a little problem with my fuel gauge.When it's full the gauge show's that in the tank is 3/4 of fuel ? Did the test of dashboard, the fuel gauge does go up and down. Did the check with test :

6.0 _ _ 352
1_6.2 kaze _ _ 353

Any idea what to check next? Any old erros , that can i repair ? It' a bit crazy.. not knowing how much fuel do i have.

Thank to all !

[damienp]

It could be that the float arm in the fuel tank has been disturbed and not been put back properly. If you dont plan to have a look inside the tank, then DO NOT let the fuel run down below the quarter tank mark, because it tells lies and you run the risk of being out of fuel all together.

[T-Cut]

I don't believe the diagnostic routine Test 6 gives anything meaningful on these cars. It may do on the BMWs from which it originates. It would probably be better to check the resistance range of each float level sender. There's one in each side of the tank. Doing the range checks however, introduces potential new issues like getting them reinstalled correctly. The advice seems to settle on living with it. However, the resistance range has been posted somewhere by Jules.

TC

[h4ck]

I woud rather have it fix, or fix by my self. But on other way.. i don't let it go under 1/4 of tank never, no need for it.

And when i fill it up full and the gauge is on 3/4 and stays there for abou 150km or so, so from that down i think it show's correct value ? :D

[chrissyboy]

is this what you may be looking for by jules ,,,,,,

Here's the readings, though I had them somewhere!
There's 6 pins on top of the Intank module (Grey circular plastic top)
The LH sender can be measured from the RH plug so no need to remove LH cover if readings are even.

If you are kneeling into driver's side back seat area, the plug pins are identified as follows:

Supply to the pump itself = Middle 2 pins
Pair of pins nearest you = RH side sender
Pins furthest away = LH side sender

Resistance readings

Motor = 2.5 ohms
Both senders read similar.
Empty tank = 5 ohms Full tank = 163 Ohms
Pretty linear in between the two levels
__________________

[T-Cut]

I'd say one or other or both float arms a binding when the fuel level is high. They stick at the 3/4 value until the level drops and they become free floating again. Since the problem corrects itself when fuel drops to 3/4, you are unlikely to run out of fuel due to the gauge being wrong. If you fill the tank up and then check the float resistances, you will easily see if they are sticking. The resistances can be measured from the external connector on the driver's side pump module.

TC

EDIT: That's it, 163ohms or so for a 'full' reading (or is that the other way around?). I suspect yours will read lower (higher?) on a full tank. It will be good evidence anyway and may enable a garage to fix it properly. Here's a drawing.

https://www.mediafire.com/convkey/200c/2mw6w5b727zkia36g.jpg

[h4ck]

Ok then , i will fill up full and mesaure it. And i shoud get same result from one and other( or similar) ? If the result is lower than 163ohms, what can garage fix? You know, here in Slovenia are non original Rover service ... so how can we fix them to send correct value ?

[T-Cut]

And I should get same result from one and other (or similar)?

With a full tank, yes.

If the result is lower than 163ohms, what can garage fix? If the readings are low (high?) then the floats are not lifting to the true 'full' position. Something must be stopping them. The usual reason is that someone has opened up the tank previously and have not refitted the modules/floats correctly. It can be difficult because the units sit on a platform in the tank. This is discussed on the forum now and then.

so how can we fix them to send correct value?Assuming both floats give the correct reading when tested outside the tank, then they must give the same readings when installed. They must be free to rise to the correct position (and to fall to the correct 'empty' position). Unfortunately, that's difficult to check without filling the tank with fuel. If the readings are still wrong you must drain it and start again. Also check that the gauge shows 'full' when both floats are lifted to 'full' postion (and 'empty'/low) when outside the tank. This will confirm that the fuel gauge system is OK. Do not bend the metal/rod arm to the floats or they will read incorrectly in use.

I would also recommend you to fit the Orange Clip to prevent any possibility of fuel filter problems later.

TC

[h4ck]

So we solved it out, t-cut you were correct, the left level sender was stuck so it didn't send correct values, not refited and installec the orange clip. All working ok + fuel gauge working !!! Many thanks !!! :bowdown: