1991 740 Turbo Instrument Panel Swap

mcclusk · Post by **mcclusk** » 01 Aug 2018, 09:10

Hello, my 740 IP odometer failed and I installed a working 940 IP. All works fine now, except for the fuel gauge, shows reserve light on and no fuel regardless of actual fuel level. Online info indicates that volvo may have changed the resistance requirements after 1991, so I am looking for a fix, if any. Thank you.

Post by **RickHaleParker** » 01 Aug 2018, 12:56

Check the solder joints on the back of the 940 IP. The ones to the fuel gauge are known to crack. Some times a solder reflow is all it takes to get the fuel gauge working.

mcclusk · Post by **mcclusk** » 01 Aug 2018, 16:45

Thank you for the advice. I do not know which wire connections do what. Can you instruct me as to which joints are for the fuel gauge? Thanks again.

Post by **RickHaleParker** » 01 Aug 2018, 18:42

You question is tipping me off, you don't have soldering experience. This should be done by somebody that knows how to solder, if it done wrong one can burn up the printed circuit.

93Regina · Post by **93Regina** » 01 Aug 2018, 23:15

mcclusk wrote: 01 Aug 2018, 16:45Can you instruct me as to which joints are for the fuel gauge?

and BAM gas gauge works!

mcclusk · Post by **mcclusk** » 02 Aug 2018, 06:46

Yes, not much soldering experience here. Also, as stated before there may be a resistance issue from the sender so i am looking for a later (posy '92) fuel sender to put in the tank and see if that fixes this. Thx again for the advice.

93Regina · Post by **93Regina** » 02 Aug 2018, 07:13

mcclusk wrote: 02 Aug 2018, 06:46Also, as stated before there may be a resistance issue from the sender...

I have a 1993-940, and dash's fuel reading always shows full...vehicle came that way.

I assume fuel-tank sender was the issue....as in someone screwed the pooch when replacing fuel pump. But, since vehicle runs fine, I use odometer.

Vehicle has over 1/4 million miles on odometer, so I assume fuel pump has been replaced once. It might be the dash unit, or fuel-tank unit.

Ohm/Volt meter is your friend....

I've driven for years with defective fuel-gauges....its a convenience....only once did I run out of fuel, and I was headed to get tank filled,

mcclusk · Post by **mcclusk** » 02 Aug 2018, 07:20

Ha, I agree. . .but a 16 year old high schooler needs a working fuel gauge or I suspect there will be some hassle from more than a few calls for a gas can delivery!

Post by **RickHaleParker** » 02 Aug 2018, 07:26

Anybody that really knows how to solder can inspect the solder joints and spot defective solder joints. Is there an electronics shop class at the school?

lummert · Post by **lummert** » 02 Aug 2018, 13:29

I've been using a VDO oil pressure gauge that is just left lying on the console of my 88 765 as a fuel gauge for several years. Never tried to figure out the problem with the gauge. For certain the problem isn't fuel sending unit related.