Hi Folks

I have both a '70 and '72 142 and both fuel gauges behave badly in exactly the same way: they read fine while full, but after you use about a quarter-tank or so the gauge just dives towards empty.

Is this a chronic sender or gauge problem that anyone has seen before?

Many thanks,

Jim
--
'58 PV444
'66 1800S
'67 122S Estate
'70 142S
'72 142E
'78 242GT
All are pretty and run except the '78 The irony!
http://www.olddeadvolvos.com

The sender is worn out.

In good condition they are very accurate. 1/2 a tank means 20 litres gone, reserve means 40 litres gone.

Same with the temp gauge, they are good too when working properly.

The gas gauge on my '75 164E makes me laugh.

You fill it up and the needle gets perfectly aligned with the full mark. Drive about 5 minutes and the needle drops like a rock to the 3/4 position where it will stay for quite a long time. Then it will slide a bit below 3/4 and then drop like a stone again to about 1/4.

It is so funny to watch. I don't think I've ever seen the needle at 1/2 and I mean ever at 1/2 it just races past it.

I think that the Volvo gas gauge is absolute proof that the Swedes have a sense of humor.

j...

That action is very unusual indeed...it sounds like maybe the wiper is hanging up somehow...as a rule the Swedes didn't intentionally build sources of entertainment into their cars...

Cheers

Jim;

I agree with other posters...Volvo fuel gauges (more likely due to sensors really) have never been known for their linearity...I recommend just getting used to the way your particular gauge reads if it's a linearity issue only...even a slowly and repeditively bouncing needle is perfectly normal as it follows sloshing fuel (gauge is direct reading with minimal electrical damping, strictly the mechanical damping of gauge which is also minimal)...needle bouncing "instantly" to the pegs is an indication of an intermitten connection along the way or at sender.

Al; Please don't confuse nonlinearity attributable to geometry of sender action with intermittency attributable to worn, oxidized, or otherwise poor and intermittent connection of sender slider...big difference in action and repair!

Cheers

Hey Ron,

No, don't fret, Your words - "Please don't confuse nonlinearity attributable to geometry of sender action with intermittency attributable to worn, oxidized, or otherwise poor and intermittent connection of sender slider...big difference in action and repair!"

You're right. I take advantage and sometimes think that others have already addressed these items. My error.

Regarding "repair", do you, or do you have a contact about repairs of the windings? I have an early 140 series sender as well as the sender in my '60 that could use a tune-up. I thought that that repair was a specialty-type of repair and since it is not a daily driver...

That's why I've lived with it for so long.

Al;

If an electrical check (with sender removed) verifies an intermittent connection as a function of float lever position, and internal inspection must be made...if surface corrosion is found (as is often the case with long-term stored vehicles, where moisture was able to do its longterm worst without the wiper occasionaly cleaning it away), great, YOU can manually clean it away and the sender will be good as new. This is a typical failure mode. If the intermittency is due to worn and eventually broken resistance wire, either the break needs to be repaired (this can be done by soldering, and loosing a turn or two woulnd't be the end of the world) or the resistance wire needs to be replaced entirely. I have some notes on this which I'd have to dig out...

Cheers

I've also had a few 140s with erratic fuel gauges.
I'd agree that is likely the sender.

Over the years I've just learned to ignore the gauge and instead just fill up at every 250 mile interval on the odometer.

Mine (70 144) goes down to about half and then dives - my vote is chronic behaviour. I'll pull the sender eventually but I am pretty unlikely to pay the going rate for a new one.

That is more extreme than usual although it is common for the second half to go quite a bit faster than the
first half because of the geometry of the sender arm. It is possible you could adjust the sender arms for better (but not really good and certainly not PERFECT) linearity.
They are just a wire with a float on the end and can be bent easily to adjust.
Have a new gasket handy.....
--
George Downs, Bartlesville, Heart of the USA!

Thanks folks! It's good to know I'm not alone with my problem.

One more question- has anyone noted odometer error in this vintage of 140 instrumentation? Even with correct tires, my '70 seems to have at least 10%, which makes the already dismal fuel economy (w' BW35) seem worse.

I think I'm going to borrow my friend's GPS and do some tests...

Thanks!

Jim
--
'58 PV444
'66 1800S
'67 122S Estate
'70 142S
'72 142E
'78 242GT
All are pretty and run except the '78 The irony!
http://www.olddeadvolvos.com

What size are you using as "correct tires"?

Smart, easy, and pretty accurate idea to use a GPS to check it. Wish I knew someone with one.

I've always just done the math to figure out the error. But you do need a tachometer to do it that way.

I hadn't checked this thread in a bit so sorry for the delay and thanks to all for input. I may pop the sender out of the '72 and look for corrosion, adjust the float, etc. I'll let folks know what I find.

Re: "correct tires" they are 165 R15 on one car and I think 165 80 15 on the other (which I've heard is slightly different from 165R). Should be close enough.
--
'58 PV444
'66 1800S
'67 122S Estate
'70 142S
'72 142E
'78 242GT
All are pretty and run except the '78 The irony!
http://www.olddeadvolvos.com

FYI
NOS Fuel tank sending units are dropping in price ($65 with 7 bids) on ebay. A recent influx of these items on the market has dropped prices down from over $100. I think earlier I had bid up to $129 on one NOS sender and lost.
Watch E-bay, seems like one should pop up again soon.

Joel
--
Antique Swedish Steel 71 142E color V#102