New guy with US '78 - Fuel gauge question
05-15-2017, 03:23 PM
#1
New guy with US '78 - Fuel gauge question
Hi there,
I picked up this '78 5 speed a few months ago at a charity auction. It has fairly well documented mileage (70K), but it was parked sometime around the turn of the century.
I'm not much of a mechanic, but thanks to the people who share their knowledge on this forum, and some luck, I was able to get it up and running decently. I've got a long to-do list still, but I'm working on a couple of issues now:
1. The fuel gauge alternates between sitting on E, showing the correct reading, twitching rapidly back and forth between E and F, or migrating slowly from the correct reading to 1/2 tank lower when I accelerate (e.g., I now have 3/4 tank; it will read the 3/4 tank at idle, but at WOT it goes down to 1/4 - 1/2 tank).
The gauge was completely non-op when I got it, sitting on E with the warning light on at all times. When I dropped the tank, I cleaned the crud from the sender (and then did it again because it was so much fun
) and cleaned the electrical contacts at the sender. It seems to be operating, so I'm guessing the fault is somewhere else. In searching the forum, I saw that a vacuum in the tank can cause the twitchy needle, but I don't seem to have any other signs of a vacuum (no tank deformity, no rush of air when I open the cap, no plugged vents that I can find). Any ideas?
2. There is an occasional hesitation or bucking on light acceleration. It's most noticeable when accelerating at idle and slow speeds (1st, 2nd or reverse), and less frequently at higher speeds when feathering the accelerator. The fuel pressures tested okay the last time I tried. Can a sticking throttle plate cause this? The plate was really balky and was causing similar symptoms before I cleaned and lubed it. I'm wondering if it is sticking at times. Any other ideas?
Thanks
Andrew
I picked up this '78 5 speed a few months ago at a charity auction. It has fairly well documented mileage (70K), but it was parked sometime around the turn of the century.
I'm not much of a mechanic, but thanks to the people who share their knowledge on this forum, and some luck, I was able to get it up and running decently. I've got a long to-do list still, but I'm working on a couple of issues now:
1. The fuel gauge alternates between sitting on E, showing the correct reading, twitching rapidly back and forth between E and F, or migrating slowly from the correct reading to 1/2 tank lower when I accelerate (e.g., I now have 3/4 tank; it will read the 3/4 tank at idle, but at WOT it goes down to 1/4 - 1/2 tank).
The gauge was completely non-op when I got it, sitting on E with the warning light on at all times. When I dropped the tank, I cleaned the crud from the sender (and then did it again because it was so much fun
) and cleaned the electrical contacts at the sender. It seems to be operating, so I'm guessing the fault is somewhere else. In searching the forum, I saw that a vacuum in the tank can cause the twitchy needle, but I don't seem to have any other signs of a vacuum (no tank deformity, no rush of air when I open the cap, no plugged vents that I can find). Any ideas?2. There is an occasional hesitation or bucking on light acceleration. It's most noticeable when accelerating at idle and slow speeds (1st, 2nd or reverse), and less frequently at higher speeds when feathering the accelerator. The fuel pressures tested okay the last time I tried. Can a sticking throttle plate cause this? The plate was really balky and was causing similar symptoms before I cleaned and lubed it. I'm wondering if it is sticking at times. Any other ideas?
Thanks
Andrew
