Checking fuel tank sender

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Danno

Checking fuel tank sender

Post by Danno »

How do I verify that my sender isn't working right? are there any voltage tests I can run. I just replaced my old cheapo digital voltmeter/ammeter/ohmmeter doohicky device with a nice new one that I'm itching to use.
So Cal Mark

Post by So Cal Mark »

a resistance test is needed to test the gauge and/or sending unit. The trouble is that it's hard to find specs on the range, since nearly every car is different.
If you remove the sending unit, attach the ohmmeter leads and move the float arm thru it's travel. You'll be looking for dead spots. From what I've seen, they usually occur in the middle of the travel since most people keep the tank about half full. The Fiat units weren't dampened, so the float bounces as fuel sloshes and that tends to wear thru the wiring in the sender. Once the unit is out of the tank, remove the cover and you'll see what I'm describing
Danno

Post by Danno »

thanks mark. sending unit isn't that expensive, but I don't want to waste money if it's something like faulty wiring....
So Cal Mark

Post by So Cal Mark »

make sure the two wires at the sender aren't crossed; one is for the low fuel light, the other for the gauge. 99.9% of the time it's the sender
mbouse

Post by mbouse »

No joke on that nearly every car is different! The stock sender coupled with the stock gauge worked very nicely in my '80, red light coming on when there was roughly 1/2 gallon left and the gauge signaled just above 0/0. Prolly just as the engineers desired.

I had an intermittant issue last year, nearly running out of gas more than once. So, i replaced the sender. I am not at all pleased with the readings i see now. Same gauge, mind you.

A needle's width above the 1/2 mark will see 4 gallons needed for a fill up. A needle's width below the 1/2 mark will see at least 6 gallons needed for a fill up. this tank has an 8 gallon capacity.

As soon as the needle hits the 1/4 mark, i better be heading to the side of the road....or the gas station better be in sight. and the red light lets me know that i have indeed ran out of gas (not before).
spider79

Post by spider79 »

Mike and all,

What is the capacity of a stock fuel tank? Now that I'm out on the road in mine, that may be important! The guage seems to be working accurately. I know my guage read 1/2, and it took 4 gallons to fill it night before last.

I'm going to try to run this tank dry, but don't want to get stranded doing it, either!

Rick
mbouse

Post by mbouse »

I would not suggest that until after you flush the tank of the 28 years of accumulated dirt, mud, grease, rust and who knows what else has settled in the bottom of that tank. Running a tank dry invites all those floating and bottom cruisin' things to get sucked up into that fuel sender, past the not so fine filter and into your..choke, choke..carburetor and engine.

You'll be doing a carb rebuild next, wonderin' why you had to add a tow bill to the week's adventure.

your half way point of 4 gallons is really accurate. the capacity is rougly 8 gallons.
spider79

Post by spider79 »

hmmm.

That's probably a good suggestion, Mike. I've actually run about a tank of gas through it so far. I should probably disconnect the fuel lines at the tank and flush it really well.

I'm not really having any fuel related issues. It just kind of stinks when it runs. I think it's old condensation, etc. exiting the system.

After driving it around, it's pretty evident that a carb rebuild is in my near future, not to mention some pretty serious vacuum line repair.
Danno

Post by Danno »

spider79 wrote:After driving it around, it's pretty evident that a carb rebuild is in my near future, not to mention some pretty serious vacuum line repair.
Do you still have the stock 28/32 carb in there? or has that been modified? I have a spare 28/32 here, it needs a rebuild (probably) too but looks to be in good working order otherwise. If you need parts just give me a shout-out. If you want the whole thing we can arrange something really cheap, then you could rebuild it without putting your car out of commission to do it. Hmmm, let me post this to others in the wanted / for sale forum here.
spider79

Post by spider79 »

Dan,

Judging from the condition of the rest of the car, I think it's the stocker. I actually haven't had the whole air cleaner assembly off of it far enough to see the carb #'s.

The P.O. said he intendid a carb rebuild or new carb. It's evident the secondaries aren't functioning properly, as the engine bogs down if you attempt to mash your foot to the floor on the accelerator. It seems to run on the primary o.k.

Again, by preliminary investigation, I'm sure I have some vacuum hose issues. (They're filthy and all look original) Thus far, I've only made it as far as giving the carb a thourough cleaning with aerosol carb cleaner.

My next goal is to tackle my non functioning tachometer and determine if it's a gauge issue or a wiring issue.

After that, it's on to the carb/ vacuum hoses/ intake. I also need to budget exhaust in there, too. I've got an Ansa muffler that's in decent shape, the cat looks ok, but the secondary muffler and piping is shot and leaks in several places. With the stinky exhaust of a newly roadworthy almost 30 year old car, it's going to be an issue quick.

Rather than replumb all the myriad vacuum lines on my '79, my initial temptation is to swap to an earlier intake and carb for the slight performance gain.

Rick
Danno

Post by Danno »

spider79 wrote:Rather than replumb all the myriad vacuum lines on my '79, my initial temptation is to swap to an earlier intake and carb for the slight performance gain.

Rick
That's what I'm working on right now. It was wayyy easier than I expected, and I knew nearly nothing about carburetors when I started! You should find it to be a breeeze!
spider79

Post by spider79 »

Dan,

Did you swap to an earlier intake and carb?

That seems to be a pretty recommended and easy upgrade for the '79 and '80's?

How far away is your car from being ready to drive? I sure stay a lot more motivated when I can keep driving my "projects". As soon as it moves to the "yard art" stage, I seem to lose my motivation!

Thanks,

Rick
Danno

Post by Danno »

spider79 wrote:Dan,

Did you swap to an earlier intake and carb?

That seems to be a pretty recommended and easy upgrade for the '79 and '80's?

How far away is your car from being ready to drive? I sure stay a lot more motivated when I can keep driving my "projects". As soon as it moves to the "yard art" stage, I seem to lose my motivation!

Thanks,

Rick
I think I can drive it around the block after some fine tuning this weekend.

I did a swap with an 1800 intake manifold and a 32adfa carb. That is VERY common I'm finding and it was pretty easy to do. I have tons of labeled pictures and now that I've done it I realize it could be done in an afternoon pretty easily if you have everything on hand. Someday this winter when I'm bored I might throw something together to help people who are challenged like me, lol. Boy it's surprising how much you can learn by reading things in manuals and on the internet!

I paid $225 +s/h handling for mine. It was a freshly rebuilt carb and the manifold was NOS, so i consider it a good deal. I've seen the pair go for much much less though, usually carb needs rebuilt at that point though. I think I remember seeing a pair go for $65 but it needed a new idle solenoid and the carb needed rebuilt.

I don't know if he has any left, but I got mine from Jon Logan at Midwest-124. He's an awesome guy to do business with. He even threw in a copy of a student workbook for the 32 adfa as well as an intake manifold gasket just to be nice. Otherwise there are probably lots of spares floating around out there.
spider79

Post by spider79 »

Jon Logan is local to me..........

I live in a suburban neighborhood with three residential streets and an elementary school and a park on it.

This summer, the elementary school parking lot was my own private slolom course and test track! I limped around with three functional brakes and bald tires, and had so much fun, it had to have been illegal. It was more fun than the gokart track. I more than got my $$$ worth out of this car just doing that.

Get it running. You'll be in heaven, even if you're too scared to drive in traffic!
Danno

Post by Danno »

spider79 wrote:JGet it running. You'll be in heaven, even if you're too scared to drive in traffic!
traffic here is 2 cars stuck behind a tractor in a no-passing zone. I ain't scared of anything (except being pulled over for not having ANY working tail or signal lights...more to come on that modication)
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