BJ8 out of fuel at 1/4 full tank

[NIB]

Took my BJ8 home from the dealer a month ago, at the way i stopped to refuel, and filled it up with 12 gal.
Last weekend i ran out of fuel, easy to hear, since the fuelpump was pumping like crazy and it was very noisy. At the time the fuel gauge was at 1/4 full tank.
I was only able to fill in 10 gal of fuel before it was full, full is as i recall 14 gal.

It seems like the fuel gauge is showing correct then, but i am not able to use the last app 4 gal of fuel.
Anyone got an idea of why?

What octane number should i use?
If I use 95 RON, i believe thats 90-91 is USA, then the engine backfires when i stop. If I use 99 RON, 94-95 in USA, then there are no problems. Is that normal?

Niels
Denmark

 

[Keoke]

Took my BJ8 home from the dealer a month ago, at the way i stopped to refuel, and filled it up with 12 gal.
Last weekend i ran out of fuel, easy to hear, since the fuelpump was pumping like crazy and it was very noisy. At the time the fuel gauge was at 1/4 full tank.
I was only able to fill in 10 gal of fuel before it was full, full is as i recall 14 gal.

It seems like the fuel gauge is showing correct then, but i am not able to use the last app 4 gal of fuel.
Anyone got an idea of why?

Well basically it is a Healey. However if you make certain that the gauge never shows less than 1/2 tank you will not be left on the side of the road.

What octane number should i use?
If I use 95 RON, i believe thats 90-91 is USA, then the engine backfires when i stop. If I use 99 RON, 94-95 in USA, then there are no problems. Is that normal?

Any time a Healey backfires it is my experience that the engine is running lean. Either it is cold with inadequate choke or improper carburetor adjustment. other than that all your experiences seem normal.---Fwiw--Keoke- :laugh:

Niels
Denmark

 

[anthony7777]

nib, my fuel guage did the exact thing showed 1/4 tank but was emty, i can hear it all now.."you spoze to use capacitors, resistors, ohm meter, volt meter, coils, lightning rods, power supply, scopes, special color wiring" etc. etc. all i did was put exactly 7 gals of fuel in the tank turned the ignition on and with the guage in hand adjusted it to read 1/2 tank, its been nuts on ever since. *mileage and results may vary, i can feel the rumbling ! :smirk:

 

[Bob_Spidell]

Took my BJ8 home from the dealer a month ago, at the way i stopped to refuel, and filled it up with 12 gal.
Last weekend i ran out of fuel, easy to hear, since the fuelpump was pumping like crazy and it was very noisy. At the time the fuel gauge was at 1/4 full tank.
I was only able to fill in 10 gal of fuel before it was full, full is as i recall 14 gal.

It seems like the fuel gauge is showing correct then, but i am not able to use the last app 4 gal of fuel.
Anyone got an idea of why?

What octane number should i use?
If I use 95 RON, i believe thats 90-91 is USA, then the engine backfires when i stop. If I use 99 RON, 94-95 in USA, then there are no problems. Is that normal?

Niels
Denmark

The only thing I can think of is there is something amiss with the fuel pickup tube. If there's a hole in the tube at about the 4g level--or, possibly, the tube is cut/broken off--the pump would suck air instead of fuel, causing the symptoms you describe.

I think--the dyno experts may correct me--that a stock BJ8 at 9.1:1 compression should run fine on 91 octane ((R+N)/2, 95 RON). If the compression is any higher--without additional cam overlap--higher octane may be required. If, by 'backfire' you mean run-on (or 'dieseling') then check timing and idle speed.

 

[Michael Oritt]

To determine whether it is the sender or a hole in the pickup as Bob suggests simply use a dipstick to see what the fuel level actually is when the fuel pumps stops supplying gas to the engine and take it from there.