Fuel System: 140 Carb: Wrong fuel sender unit

[tonydgray]

Hi guys
I recently bought my first Volvo, a 73 145 Deluxe. I have a problem with the fuel gauge in that it reads a lot higher that what it should. For example, if the tank is filled up the needle goes right around out of view and when the tank is nearly empty the needle is actually on the full mark.
I noticed going through old receipts that one of its owners back in 2006 bought a brand new sender, what I am wondering is if this was the wrong one at that time but the then owner could not be bothered to sort it out.
Any thoughts on what I may be able to do and oh, where is the best place to get parts for the old timers? (I need to get some tailgate struts!)
Thanks
Tony

[laptoprob]

Hi Tony,
Welcome! Good choice. You will love the room in the 145. The fuel sender in the '73 model is different than the years before, but the older ones won't fit properly. So if your sender fits nicely, it might be bent. You could take it out and figure out where 'empty' should be. The floater should then be way down ofcourse.
I have two spares, but I'm in Holland....

[Clan]

if the temperature gauge is doing the same thing it will be the voltage regulator for the instruments ..

[tonydgray]

Thanks guys

The temp seems to functioning fine so chances are I can rule out the voltage regulator, cheers Clan.

I'll have a check how my sender is fitted to see if its the right one, hopefully it is. It looks like I may have to get my hands dirty and see if it is bent, I'll keep you posted, cheers laptoprob

[laptoprob]

Originally Posted by tonydgray

Thanks guys

The temp seems to functioning fine so chances are I can rule out the voltage regulator, cheers Clan.

I'll have a check how my sender is fitted to see if its the right one, hopefully it is. It looks like I may have to get my hands dirty and see if it is bent, I'll keep you posted, cheers laptoprob

It may also be some electrical error. The dashboard readout says 'empty' with infinite resistance, so wiring may be damaged or interrupted.

[tonydgray]

Its taken a while to get around to removing the fuel sender to see if it is bent or not. Took a quick look last night but could not work out how to get the bugger out. There is a round metal disc with four locating grooves. I made a makeshift tool to fit into two of the grooves in order to turn but I just want to make sure which way and how much it actually turns.

Is is threaded and hence turns around a few rotations or does it kind of click into place with minimal rotation. Oh, also clockwise or anti-clockwise to remove.

The haynes manual has been no help with this one unfortunately.

Cheers

Tony

[Clan]

you give it about 1/4 turn anti-clockwise to release it ... then guide it out ...

[tonydgray]

You will be able to start charging for this shortly!!

Thanks again Clan

[tonydgray]

Well I got to fuel sender out last night and performed the following check:

Manually moved the float to the empty position - the fuel gauge read half a tank

Manually moved the float to the full position - the fuel gauge read maximum

The temperature gauge seems to function correctly, needle in the middle when engine warm, so I'm assuming that the voltage regulator is ok. I'm not sure of what to try next really, any ideas?

Oh the resistance readings from full to empty on the sender are 8 ohms to 70 ohms.

Cheers
Tony

[Clan]

on the 1974 240 there was a test . connect a 68 ohm resistor in place of the tank sensor and the gauge should read 3/4 +- the needle width .. i would think the 140 would be very similar in which case you might be looking for more resistance than 70 ohms when fully empty .