• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

Fuel Pump Ticking

mylesw

Jedi Hopeful
Offline
Hello

The SU fuel pump on my BT7 never stops ticking when the engine is switched off. My understanding of these pumps is that when the engine is not running and the ignition is on that the pump will build up pressure in the system and then stop (until the engine is turned on of course). Therefore I suspect I have a small fuel leak somewhere, the question is, how to I find out where it is? I have already pretty much tightened up everything I can.

Thanks

Myles
 

Patrick67BJ8

Obi Wan
Silver
Country flag
Offline
Hello

The SU fuel pump on my BT7 never stops ticking when the engine is switched off. My understanding of these pumps is that when the engine is not running and the ignition is on that the pump will build up pressure in the system and then stop (until the engine is turned on of course). Therefore I suspect I have a small fuel leak somewhere, the question is, how to I find out where it is? I have already pretty much tightened up everything I can.

Thanks

Myles
Not all pumps stop clicking when pressure is built up with the engine not running but will nearly stop their clicking.

Smell fuel anywhere? Is your overflow tubes working properly and not plugged? Fuel can come out of the carb float bowl tops(this is the black vinyl tubing) and also the intake manifolds copper drain tubes. Somethimes people clamp off the copper drain pipes because they think the engine is running rough due to airleaks from the copper drain tubes. Fuel coming out of these is from leaky jets.
 

Bob_Spidell

Yoda
Gold
Country flag
Offline
Most pumps will cycle every 5-10 seconds with the engine turned off (they bleed down internally). If the pump cycles more often than that with the engine off it's often caused by an air leak on the intake side.
 
5

57_BN4

Guest
Guest
Offline
Check that it is in fact an SU pump not a similar looking replacement one which are meant to tick all the time. Constant even ticking from an SU is most likely a stuck or dirty valve. Random clattering noise is more likely to be air leaking in. They are pretty easy to get at by removing a rear seat. Andy.
 

RAC68

Darth Vader
Offline
Hi Myles,

I am a little confused. As I understand, power to the fuel pump is cut when the key is turned off and the pump should not tick. As I read your question, are you indicating that the engine is not running but the key is in the “ON” position? If this is true, you may not have a problem unless the ticking frequency is rapid as well as continuous.

The SU fuel pump’s check valve will never be sufficient to completely stop flow-back when the “ON” switch is put to the “OFF” position. As a result, fuel pressure will be gradually lost after power is not delivered to the pump and, when the key is turned to the “ON” position, a re-pressurization of the fuel system (with rapid ticking) will take place.

You may, however, have a real problem if the pump is ticking because power is being delivered to the pump without the key in the “ON” position. If this is true, I would be looking for a short.

Hope this helps,
Ray (64BJ8P1)
 

Healey 100

Jedi Warrior
Offline
If the needle and seat in either one of the carbs has a slow leak, the fuel will simply flow above the main jet and drip into the engine. So no leak will be detected and the SU will keep clicking away. Only symptom will be a flooded engine if you leave the key on with the engine stopped for a while. Same effect can happen if the float levels are set too high so the fuel overflows the main jet. Most SU's spec the float level so the fuel level is a quarter inch below the top of the main jet. If all is set right, the clicking really should stop unless that check valve is leaky in the pump.
 

Patrick67BJ8

Obi Wan
Silver
Country flag
Offline
If the needle and seat in either one of the carbs has a slow leak, the fuel will simply flow above the main jet and drip into the engine. So no leak will be detected and the SU will keep clicking away. Only symptom will be a flooded engine if you leave the key on with the engine stopped for a while. Same effect can happen if the float levels are set too high so the fuel overflows the main jet. Most SU's spec the float level so the fuel level is a quarter inch below the top of the main jet. If all is set right, the clicking really should stop unless that check valve is leaky in the pump.
If the fuel is seeping above the main jet it will get into the intake manifold and find its way to the ends of the intake manifold where it will drip out of the copper tubing/pipes...at least that's the way it works on my BJ8 which I've owned since '72.
 
Similar threads
Thread starter Title Forum Replies Date
D Fuel Pump Ticking but Not Pumping Austin Healey 8
Cutrog1 Fuel Pump Ticking Austin Healey 13
warwick-steve Ticking fuel pump Austin Healey 7
AH67 facet fuel pump never stops ticking. Austin Healey 6
6 Solid State SU Fuel Pump Ticking: Constant? Austin Healey 4
B New fuel pump - loud ticking, now fuel spraying! Austin Healey 33
B TR4/4A AC Fuel Pump Priming Lever Stuck Triumph 10
Q TR2/3/3A 61 TR3A Fuel Pump Triumph 4
D Wanted Square body LCS fuel pump Austin Healey Classifieds 13
D Wanted Wanted square body fuel pump Jaguar Classifieds 0
D TR4/4A TR4a Fuel Pump Triumph 10
RJS TR4/4A Fuel Pump Gasket Triumph 8
D MGB Fuel Pump MG 2
Martinld123 Electric Fuel Pump Austin Healey 6
S TR2/3/3A Fuel Pump??? Triumph 14
A Spitfire Fuel Pump Triumph 5
A Spitfire Spitfire Fuel pump issues Triumph 5
K TR2/3/3A Fuel line routing from pump to carbs Triumph 7
A GT6 Fuel Pump Leaking at out port GT6 MK3 Triumph 0
wkilleffer MGB 1974 MGB SU fuel pump voltage issue MG 11
S fuel pump upgrade Spridgets 0
S Sprite Fuel Pump Upgrade Austin Healey 1
F TR4/4A New to forum - Rebuilt Fuel Pump and weeping float bowl Triumph 9
P XJ12 Fuel pump relay 85 Jaguar 4
petnatcar Fuel Pump Upgrade Austin Healey 2
R Electronic Conversion on an SU Fuel Pump? Restoration & Tools 2
T TR6 Fuel pump lines Triumph 2
1 TR2/3/3A TR3 Fuel Pump Thread Type? Triumph 4
R Electric fuel pump wiring Spridgets 4
T SU Fuel Pump Mounting Austin Healey 5
D TR2/3/3A More Fuel pump questions. Triumph 10
Donald1107 59 TR3A Fuel Pump Triumph 48
BobHaskell SU Fuel Pump Pressure Austin Healey 1
MGTF1250Dave T-Series MG TF fuel line from tank to pump MG 3
S SU fuel pump servicing Austin Healey 4
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
G Inertia Cut-Off Switch - E-Fuel Pump to Ignition [Key] Switch Austin Healey 3
vette A Quiet SU Fuel Pump Austin Healey 2
A TR4/4A AC Fuel Pump stuff Triumph 11
AngliaGT Fuel Pump Problems Spridgets 2
B SU Fuel Pump Parts Austin Healey 8
B TR4/4A Mechanical fuel pump vs electric Triumph 16
P TR6 TR6 fuel pump question - glass bowl pump correct? Triumph 8
J TR4/4A Fuel pump saga Triumph 4
longbridgehealey Fuel pump racing, no gas Austin Healey 26
D General TR Fuel filter before the pump. Triumph 2
T 66 Austin Healey fuel pump replaced Austin Healey 30

Similar threads

Top