So the fuel gauge in my 77 decided to take a dump on me.

Actually it was a slow death over about two weeks time. At first it was just bouncing around mid tank. I though it was just normal fluctuations relating to uphill/downhill orientation. Later when I filled up it topped out like normal, then slipped to about half tank within 10-15 minutes. After that it started dipping down to zero, and slipping back up for a bit. Now she's dead set on zero and don't move a twitch.

SO... what's the concensus? should I start with the gauge itself (dash)? Or do you guys think it's the sending unit? (is the float solid or hollow?)

Bah! I really don't wanna hafta deal with this!

 

My 93 did this for well over a year and when I did my SAS I had to drop the tank. I figured that would be a good time to check the sender. Turns out the sender was bad and after seeing how it works the symptoms made sense.

The float pivots on a lever about a point as the gas level changes. This arm then wipes across a variable resister so the resistance changes as the level changes. There was a dead spot in the resister where the arm had worn through the contacts so the resistance went to infinity and the gauge thought the tank was empty.

I've never taken apart a dash so I don't know how painful it is, but dropping the tank wasn't too bad with a floor jack and a friend to help. My guess is it's the sender.

On a side note I had also figured out that I kept my gas tank filled to about 3/4 tank most of the time.

 

Symptoms sound very similar to when my fuel sending unit went out. Replaced it and it fixed the problem. Never opened up the dash to look at the gauge. I vote for the sending unit.

-Scubaduck

 

Don't....at least not for now...you;'ll live.

 

On the upside, the situation forced me to note milage on a short road-trip over the weekend.

Seems like the new mill is doing right by me....253 miles on 10.388 gallons.....I'm getting around 24 MPG on the highway!

 

that's pretty good for a 20R! i could push mine to 20mpg or so, but i drove it like i had an egg under the pedal, since i thought it could blow at any time!

 

Lest you forget Kyle I did an engine swap earlier this year. I'm running a hybrid almost identical to yours! (except for the manifold and carb)

I'm still running a stock manifold and 20r carb for break-in (which is done by now, so my webber goes on soon!) And I JUST got my replacement dizzy yesterday! YES.. I'm STILL running that old dizzy with no vacuum advance!:pat:

I'm not sure if the new dizzy will help or hurt my milage. I'm afriad if I get more low end power I'll always have my foot in it!

 

dredged from the deep for an update.

My fuel pump decided to join the sending unit so I wound up having to drop the tank anyway. I called the local parts store, and found out that NO ONE in the aftermarket is making a fuel sending unit for toyota!

SOOooo I decided that I couldn't make it any deader than it already was and cracked into it. Simple little device really. After looking it over for a few minutes, I noticed that the resistor coil has a small metal tab which is soldered to a post which the 'hot' wire attaches to, and this tab had pulled away from the solder. A few seconds withthe 'cold-heat' soldering iron and that problem was fixed.

I also noticed the the resitor coil was actually just a bunch of enameled 'magnet wire' wrapped around a plastic block with a ridge in it where the contact rode. Most of the enamel had peeled off leaving quite a bit of the wire exposed. As closely spaced as a few of these wraps were, I postulated that it was possible there would be a short between a few of them which could lead to false readings. So I dug out my sewing kit(!), grabbed a straight pin and spent a few minutes carefully spacing out the closest wires. Then I raided the medicine cabinet for some clear nail polish and 'glued' them in place on the edge of the block leaving the contact ridge exposed.

Seems to work fine now. The needle moves when the key is on, but the tank is almost empty from the 'drop' procedure, so I don't know for sure how accurate it is.

On a side note, I was impressed with just how EASY it is to R&R the fuel tank on my truck! I started about 10am, and got done about 1pm....and that includes a couple of breaks, dismounting/remounting the fuel pump along with it's attendant rewiring, and the time I spent futzing with the sending unit. I was really sweating tring to do this solo but it's quite simple.....I even had the tank about 1/2 full when I dropped it! (nothing I would reccomend, but I only had one 6.5 gal gas can handy, and I had just filled up the day before it died)

 

Good work! On a completely unrelated matter, love the quote in your sig. I've about 200 pages left to read in Atlas Shrugged.