S40 V40 Cars: - Petrol pump issues?

Harry S · Oct 8th, 2012, 06:20

Hi guys,

My v40 is suddenly giving the wrong reading. It stopped reading full and used to stops at 3/4 mark. I removed the plunger thingy from the tank and cleaned it. It was not dirty but using a earbud i cleaned the float points, etc ans reinstalled it. After that i filled the car. It got stuck in two places and then fter 5sec continued moving. Currently i think it may be stuck at 3/4 full. Is there a detailed discription of how i coyld clean it more thoroughly? Would that work or should i try to get a new one? I drive a 2001 volvo V40, 2L auto.
How good is the second hand ones? Or is it a 50/50 ratio it will or wont work?

gatos · Oct 8th, 2012, 07:18

Have you checked the thin wires in the pump/sender unit? The solder can get fragile and a bit of resoldering will most probably sort out the problem.

Harry S · Oct 8th, 2012, 11:45

Thanks GatosM will look this evening.

jeffreyt · Oct 11th, 2012, 12:16

I took the pump/sender unit out of the V40 yesterday to check it as have had some erratic reading recently.
It looked like a new unit ,I cleaned the contacts anyway, and the fragile looking solder blobs were still doing their job.
Checking the paperwork later I found an invoice for a new pump/sender unit back in '09 so it was fairly new.
Gatos's guide is really good and its quite easy to do.
just one thing, don't tape off the ends of the fuel lines to stop dirt going down them ,the petrol residue melts the adhesive on the tape and you end up with a gooey meess on the end of the fuel lines,the exact opposite of what you are trying to avoid! Just wrap a bit of clean cloth round each line.

gatos · Oct 11th, 2012, 13:05

So is your problem solved now or not?

jeffreyt · Oct 11th, 2012, 19:39

the fuel guage is steady at the moment reading just below half full and this looks about right with the level of the petrol that I could see in the tank.
It seems to happen after a long run when the gauge will suddenly go from say half full to nearly empty.
So not sure at the moment,will see what happens on next long run.

DrDeAtH · Oct 13th, 2012, 21:30

... mine seems to have died again after the 3rd fix... puzzled now...

Oct 8th, 2012, 06:20	#1
Harry S Harry S Last Online: Sep 2nd, 2022 22:09 Join Date: Apr 2012 Location: Pretoria, South Africa	Petrol pump issues? Hi guys, My v40 is suddenly giving the wrong reading. It stopped reading full and used to stops at 3/4 mark. I removed the plunger thingy from the tank and cleaned it. It was not dirty but using a earbud i cleaned the float points, etc ans reinstalled it. After that i filled the car. It got stuck in two places and then fter 5sec continued moving. Currently i think it may be stuck at 3/4 full. Is there a detailed discription of how i coyld clean it more thoroughly? Would that work or should i try to get a new one? I drive a 2001 volvo V40, 2L auto. How good is the second hand ones? Or is it a 50/50 ratio it will or wont work?

Oct 8th, 2012, 07:18	#2
gatos Premier Member Last Online: Nov 15th, 2022 21:34 Join Date: Apr 2010 Location: London / Essex	Have you checked the thin wires in the pump/sender unit? The solder can get fragile and a bit of resoldering will most probably sort out the problem. __________________ Current car: 2002 S40 1.9D, 1992 240SE Nullius in Verba

Oct 11th, 2012, 13:05	#5
gatos Premier Member Last Online: Nov 15th, 2022 21:34 Join Date: Apr 2010 Location: London / Essex	So is your problem solved now or not? __________________ Current car: 2002 S40 1.9D, 1992 240SE Nullius in Verba

Oct 8th, 2012, 11:45	#3
Harry S Harry S Last Online: Sep 2nd, 2022 22:09 Join Date: Apr 2012 Location: Pretoria, South Africa	Thanks GatosM will look this evening.

Oct 11th, 2012, 12:16	#4
jeffreyt Member Last Online: Jan 7th, 2017 15:06 Join Date: Dec 2009 Location: Twyford	I took the pump/sender unit out of the V40 yesterday to check it as have had some erratic reading recently. It looked like a new unit ,I cleaned the contacts anyway, and the fragile looking solder blobs were still doing their job. Checking the paperwork later I found an invoice for a new pump/sender unit back in '09 so it was fairly new. Gatos's guide is really good and its quite easy to do. just one thing, don't tape off the ends of the fuel lines to stop dirt going down them ,the petrol residue melts the adhesive on the tape and you end up with a gooey meess on the end of the fuel lines,the exact opposite of what you are trying to avoid! Just wrap a bit of clean cloth round each line.

Oct 11th, 2012, 19:39	#6
jeffreyt Member Last Online: Jan 7th, 2017 15:06 Join Date: Dec 2009 Location: Twyford	the fuel guage is steady at the moment reading just below half full and this looks about right with the level of the petrol that I could see in the tank. It seems to happen after a long run when the gauge will suddenly go from say half full to nearly empty. So not sure at the moment,will see what happens on next long run.

Oct 13th, 2012, 21:30	#7
DrDeAtH Junior Member Last Online: Jun 3rd, 2018 22:00 Join Date: Sep 2012 Location: Hertford	... mine seems to have died again after the 3rd fix... puzzled now...

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