• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

Fuel starvation

mgtf328

Jedi Hopeful
Country flag
Offline
Coming up a steep hill this weekend my BJ8 started to falter and backfire. Returning to level ground everything returned to normal. I'm guessing the fuel level must have got so low it ran to the back of the tank whilst coming up the hill. I hadn't realised the tank was so low as the gauge is very erratic/unreliable. First time for this to happen so maybe the sender is broken.

I have an after market aluminium fuel tank and the take off is on the side of the tank at the front and at the top rather than the bottom so there must be a pipe inside that runs from top to the bottom of the tank. Also, I don't think that there can be any/many baffles in the tank because when the tank is less that half full you can here the fuel splashing around when you go around sharp corners.

The gauge is relatively new so I'll start with testing the sender. I can't think how I could test the sender in situ so I guess I'm going to have to take it out and replace it if necessary. Then I think I'm going to try Dan Hardies fix of fitting a 1 farad capacitor across the sender terminals so I'd be grateful to know if anyone has any experience of how effective this fix is and if it gives a more reliable indication of how much fuel is in the tank.

Thanks
AJ
 

Bob Hughes

Luke Skywalker
Country flag
Offline
Hey AJ
Yep, there is a pipe inside but it is all at the 'front' of the tank so on a really steep hill and really low on fuel it would seem to be empty.

I had a home made Ali tank and there was at least one baffle in there but you could still hear the fuel splashing about on occasions.

Some one has posted a test on the sender some time ago - it was in a glass tank if I recall and wired up to a battery and a fuel gauge, you may be able to search for it.

Alternatively you could try using a stick, marking the position of the bottom of the tank and also the top of the tank and all points then in between and relate that to the sender. You could also remove the sender and check that the float is not leaking. Funnily enough my old float rocked about a bit, according to the gauge, and it is to be expected, when the juice was splashing about in the tank but it was quite reliable, further more the arm had been cobbled up for some reason. I am in the middle of replacing the boot floor and have a new tank and sender in the garage waiting to be installed so I will be have some fun and games then myself.

:cheers:

Bob
 
Country flag
Offline
It could also be that fuel flow is restricted by debris in the tank and/or a partial clogging of the little filter built into your SU fuel pump--or perhaps there is an aftermarket inline filter somewhere in your supply line that needs cleaning.
 

dancrim

Jedi Hopeful
Offline
Pull the sender out of the tank, leave the wire on it, and using another wire with alligator clips
ground the body of the sender. Turn on the key and move the sending unit lever slowly up and
down. Have a friend watch the gauge. It should go from empty to full as the lever is moved.
 

Madflyer

Jedi Knight
Country flag
Offline
In any case stick for fuel level, many times float on sender arm will go bad leak removal is the the only fix. Steep hills are only a problem when long and fuel pump can not keep up with more gas peddle. If the the hill is not near run in lower gear at high RPM and see if RPM goes flat it should only take a mile. My TR 6 went flat RPM at about 95 MPH long straight road carb adj. was needed. Madflyer
 
OP
M

mgtf328

Jedi Hopeful
Country flag
Offline
Thanks guys, I'm going to take it out to test it with an ohm meter but made the stupid mistake of filling the tank up so I need to wait a while for the level to go down.
I have Petronix fitted and am a bit paranoid about leaving the ignition on for too long but thinking about it perhaps I could protect the Petronix by taking the dizzy cap of first, not sure about that.
I ordered a capacitor to fit across the terminals. I'll let you know what I find out and whether the capacitor makes any difference to the gauge fluctuation.

AJ
 
Country flag
Offline
Pertronix switches primary current 'upstream' of the coil, whereas points switch 'downstream.' When I need to have my cars' ignition in the 'run' position for some reason, I disconnect either of the primary wires to the coil. Current can't flow through the Pertronix, even if it's in the forward-biased (current passing) state if the circuit is open. Taking the distributor cap off won't work, since current would still flow through the coil.
 
Similar threads
Thread starter Title Forum Replies Date
jhorton3 Fuel Pump Starvation? Spridgets 6
T Bad coil mimicking fuel starvation? Triumph 17
J fuel starvation on my 100 Austin Healey 3
J Fuel starvation Healey 100 Austin Healey 18
T TR4/4A TR4A Fuel Starvation problem: Dry float bowls Triumph 8
W TR4/4A TR4A fuel starvation. Triumph 4
FlyingCat Spitfire Fuel Sender Unit Triumph 2
G Twin HS4 Su's leaking fuel Spridgets 15
G General MG Leaking Fuel on twin HS4's 1500 MG Midget MG 4
JPSmit Fuel tank sender - how does it work? Spridgets 4
Boink Early Mini Fuel Gauge - adjusting it British Motor Corp 0
RJS General TR Winter Blend Fuel Triumph 1
D TR2/3/3A More Fuel pump questions. Triumph 10
Donald1107 59 TR3A Fuel Pump Triumph 26
BobHaskell SU Fuel Pump Pressure Austin Healey 1
S Large capacity fuel tank Spridgets 1
D TR2/3/3A rearmost fuel line question Triumph 5
fpstude TR4/4A Fuel Pipes Connector Triumph 4
Healey Nut Fuel Sender Austin Healey 3
Cutrog1 Fuel Pump Ticking Austin Healey 13
S WANTED: Healey BN1 "Smiths" Fuel Gauge (Dead or Alive) Austin Healey Classifieds 3
Cutrog1 BJ8 Fuel Tube Installation Austin Healey 10
MGTF1250Dave T-Series MG TF fuel line from tank to pump MG 3
D TR6 1972 TR-6 Fuel Vapor Recovery System Triumph 4
JPSmit Fuel line - gas tank question Restoration & Tools 5
R TR2/3/3A Fuel Gauge Triumph 19
M TR2/3/3A Fuel Line Fitting at the Tank. Triumph 5
S SU fuel pump servicing Austin Healey 4
steveg TR6 Source for fuel line P-clip Triumph 17
71TR6 TR2/3/3A AC Fuel Pump Lever Triumph 10
E MGB 1965 mgb fuel pump removal MG 2
D For Sale Su fuel pump Other British Classifieds 5
D For Sale Su fuel pump Austin Healey Classifieds 5
BLong63AH BJ7 Hard Fuel Lines Austin Healey 20
Michael Oritt SU H6 carb for Le Mans--order of assembly of fuel bowl lid Austin Healey 2
TRopic6 For Sale TR2/3 Brass Fuel Shutoff Tap [for parts] Triumph Classifieds 0
G Inertia Cut-Off Switch - E-Fuel Pump to Ignition [Key] Switch Austin Healey 3
Ljohns New Midget/Sprite Fuel Tank Austin Healey Classifieds 1
T Wanted Smiths fuel gauge for Mk 1 Bugeye Sprite [FG2530/31] Spridgets Classified 1
B AH Spares Fast-Flow Fuel Manifold Austin Healey 2
S Fuel gauge calibration procedure Austin Healey 18
I TR6 TR6 - Fuel leaking from bottom of Evaporator Canister Triumph 11
F Spitfire Triumph Spitfire , what fuel to run Her on with no engine history? Triumph 11
C MGA Fuel gauge question MG 7
vette A Quiet SU Fuel Pump Austin Healey 2
B Under bonnet fuel Austin Healey 15
S Wanted 1959 Bugeye Fuel Gauge Austin Healey Classifieds 0
A TR4/4A AC Fuel Pump stuff Triumph 11
AngliaGT Fuel Pump Problems Spridgets 2
B SU Fuel Pump Parts Austin Healey 8

Similar threads

Top