fuel guage reading question

[76Datsun280z]

I wonder how many gallons left need to be in the tank to get that red light to come on then?

[moritz55]

Here's some of my experience on my 1973 240z. I just installed new fuel sending unit and don't have a fuel light but after calibrating it I notcied a couple of things.

1) When filling the tank (I think it's a 15.5gal tank), the pump clicks off at the 13gal mark. The fuel gage reads just over 3/4 Full (closer to 7/8 full). and the gage reads Full.

2) The 1st Half a tank reading on the fuel gage is really 1/3 the capacity(about 4-5gals) where as the 2nd Half tank readings measure 2/3 of the tank capacity (8-9gals).

3) When the fuel gage reads empty, square on the E line, I have approx. 2 gals left. I can go for 45-50miles before running the tank to empty. I actually tried this and carried a 2gal tank with me and validate it.

This is very similar to how my original 1970 240z tank measured when it was factory installed many years ago.

I suppose I can recalibrate the fuel sensor, but for now it works for me.

[moritz55]

I missed type item #1 on the above posting..... it should read.

Corrected Point:

1) When filling the tank (I think it's a 15.5gal tank), the pump clicks off at the 13gal mark. The fuel gage reads just over 3/4 Full (closer to 7/8 full).

Sorry

[TomoHawk]

When filling the tank (I think it's a 15.5gal tank), the pump clicks off at the 13gal mark.

What do you mean by "the pump clicks off?"

thxZ

[KDMatt]

What do you mean by "the pump clicks off?"

thxZ

I think he's talking about the gas pump, how when it senses liquid or 'foam' it turns itself off to keep you from overfilling.

[zhead240]

clymer service handbook list tank capacity of 60 litres or 15.8 U S gallons. that's 13.2 imperial gallons. i couldn't find this info in my FSM. also whenever i get on E or a titch below it usually take 45 to 48 litre, thus i have 12 to 15 left. when full guage reads 3/4. when trip meter goes over 200 miles i start looking for a gas station.

[moritz55]

Sorry I wasn't clear... I mean the gas pump sensor. When it foams or fumes click it off... I have 2+ gals left in the tank befoe I top it fully up to 15+ gals...

[TomoHawk]

OK, I gotcha. I'll let the pump click off myself, then add a little more carefully. I got a little shock when I looked down the filler neck the last time and I saw the top of the gasoline! I guess the 280Z doesn't have the junk screen or the little hole for the pump nozzle like new cars do. Better be careful not to stick in the leaded or diesel nozzle!

thxZ

[Walter Moore]

TomoHawk, if your 78 doesn't have the fuel nozzle restriction it means someone removed it at some point, because all cars sold in the U.S. from the 1975 model year on required unleaded gas and the small fuel nozzle restriction was required.

Back on the subject of the thread, I just put fuel in my car's tank a week or so back so I could finally start the thing. 5 gallons (U.S.) just barely moved the gauge off of the Empty mark. I haven't actually driven the car anywhere yet because I haven't put on the real tires and wheels.

(I just let the neighbors listen to the engine idle...)

[Carl Beck]

TomoHawk, if your 78 doesn't have the fuel nozzle restriction it means someone removed it at some point, because all cars sold in the U.S. from the 1975 model year on required unleaded gas and the small fuel nozzle restriction was required.

Hi Walter:

Gee.. I don't remember it being that way. I was thinking that in 1975 only certain new cars equipped with catalytic converters required unleaded fuel, and thus they had the restricted fuel filler, with the required "Unleaded Fuel Only" label, to protect the cat.

Indeed the 75 280Z didn't require a catalytic converter to pass the US EPA Emissions Standards - and only the Z's sold in California required a catalytic converter to comply with the stricter CARB standards- and thus the restricted fuel filler. The Parts Catalog lists different part numbers for the "Federal" model and the "California" model... from Dec. 74 to July 76

FWIW,

Carl

[sblake01]

The microfiche also lists a Fed and Cal for 8/76 up 'ASSY-TUBE FILLER UPPER'. Actually four different ones. A Fed and Cal for the 2 seater and a Fed and Cal for the 2+2.

[Walter Moore]

Hi Walter:

Gee.. I don't remember it being that way.

FWIW,

Carl

Sorry about that Carl... I checked the parts CD and you appear to be correct.

Which puzzles me a lot... I suffer from American-car-tus. I know that starting with the 1975 model year all the cars that belonged to my friends and family had a converter. (and the fuel restriction in the tank.) but except for my mom's 79' Honda (which had a converter also) those were all American cars. I confess that I have always assumed that all cars were that way.

By the time that I was on my own looking at new cars at the dealer lots it was the early 80's and by then all cars (Datsuns included) had converters.

(The emission rules were tightened in 81 as I recall.)

I am more than a little puzzled at how Nissan managed to meet the 1975 air pollution standards without a converter, when every other brand that I know of (Including VW, Volvo, etc) used them in that era.

We had a 74' Datsun at one point (In the 80's) which didn't have a converter, but none of the 74 models I have seen from any maker had one either...

I just assumed that 1975 was a bright line for converter vs not. I learn new things all the time.