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Hello all: I installed a solid state electronic SU fuel pump in my '62 BT-7 a few months ago. The pump is working fine, ie the car runs well both at idle and driving, including the freeway at higher speeds. Here's the issue: Once the ignition is on there's the usual SU ticking from the pump. Ordinarily with stock pumps the ticking stops after a few seconds, then I'd fire up the engine. With this new solid state pump it rapidly ticks, then slows significantly but never completely stops ticking. Maybe a tick every second or two. I've sealed & tightened every connection from the tank to the pump, including all threaded connections (with teflon tape), tightened all fuel clamps, new fuel lines, etc. No visible cracks in the pump body. Question: It seems the pump is slightly cavitating, but I thought I'd read somewhere in the distant past that the solid state pumps were different in that they never fully stopped ticking...??? Maybe I'm imagining that...Again, it runs fine but this is a pricey piece of gear that I don't want to burn out. Thoughts?
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Solid State SU Fuel Pump Ticking: Constant?
- Thread starter 62BT7
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Keoke
Great Pumpkin
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Hi 62BT7, Sounds like it is ok to me. However, there are some aftermarket electronic pumps, Not SU's, that click all the time and those are the ones you probably heard being discussed. Or in some cases a bad input fuel line on a new SU install which lets the pump suck air and cycle continuously.---Keoke
bob hughes
Luke Skywalker
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I have never waited long enough after the pump has initially stopped to listen for residual ticks from my solid state pump, but I would have thought that it was not unusual to happen, to maintain pressure in the line.
Get her going and enjoy that deep throated sound.
Bob
Get her going and enjoy that deep throated sound.
Bob
Wondering if you ever resolved this issue ?
I have the same problem AH BJ8
New SU AZX 1308EN never completely shuts off when engine not running. No leaks and have tightemed all inlets numerous times.
Car runs fine. Don't believe have fuel tank issue as the old points pump used to shut off properly.
Ticking increases dramatically when idling.
Different valves in these ?
Another mystery ...
rg
I have the same problem AH BJ8
New SU AZX 1308EN never completely shuts off when engine not running. No leaks and have tightemed all inlets numerous times.
Car runs fine. Don't believe have fuel tank issue as the old points pump used to shut off properly.
Ticking increases dramatically when idling.
Different valves in these ?
Another mystery ...
rg
Offline
I would take a look at the inlet/ outlet valve on the fuel pump. If the Ĺ‚inlet part of the valve were only closing partially when fuel was being pumped forward it may still push enough fuel to the carbs but won't build enough pressure because it is leaking back to the tank with each push just enough to keep it pumping constantly. If it isn't an overflowing bowl or leak I cannot think of anything else it could be. Some debris caught in it or excessive wear might be the culprit.
Bob_Spidell
Yoda
Offline
The pumps will pump sporadically--maybe every 15-30s or so--with the engine off, and key on; there is some leakage between the two valves (don't leave the key on very long, esp. if you have electronic ignition). This may be by design; if the pump 'locks up' current will keep flowing through the pump body and it will overheat. If it's pumping more often than that it is one of two things:
1) an air leak on the intake side. You can tighten the snot out of the hard fiber washers and still not get a perfect seal and they compress (I soak them in WD40 before installing). Note S.U. eventually used O-rings on the pump fittings.
2) the pump is defective or there is an inherent flaw in the design.
My experience with these pumps goes back 40 years. Some claim the original points type will last forever, it's been hit-or-miss for me (I have enough parts to build 3 or 4 pumps sitting on the shelf). The design of the pumps has changed over the years--esp. the electrical part--indicating to me that S.U. knew of the issues. The earliest pumps had nothing to mitigate points deterioration, then they tried capacitors/condensers, then diodes, then eventually 'solid state.' I have tried:
- capacitors
- diodes
- points-driven power transistor
- transils (bi-directional breakdown or 'Zener' diodes)
- S.U.'s own SS conversion
- S.U. SS pumps 'out-of-the-box'
I worked for years with the late Dave DuBois, whose retirement project was trying to perfect these pumps. He designed the transistor conversion, but found the current through the points was inadequate to clean them. Then he designed his own circuit that used an optical 'chopper' switch; again, my experience was less-than-satisfactory.
On long road trips I carry two spare pumps; I can swap a pump out in 20minutes.
1) an air leak on the intake side. You can tighten the snot out of the hard fiber washers and still not get a perfect seal and they compress (I soak them in WD40 before installing). Note S.U. eventually used O-rings on the pump fittings.
2) the pump is defective or there is an inherent flaw in the design.
My experience with these pumps goes back 40 years. Some claim the original points type will last forever, it's been hit-or-miss for me (I have enough parts to build 3 or 4 pumps sitting on the shelf). The design of the pumps has changed over the years--esp. the electrical part--indicating to me that S.U. knew of the issues. The earliest pumps had nothing to mitigate points deterioration, then they tried capacitors/condensers, then diodes, then eventually 'solid state.' I have tried:
- capacitors
- diodes
- points-driven power transistor
- transils (bi-directional breakdown or 'Zener' diodes)
- S.U.'s own SS conversion
- S.U. SS pumps 'out-of-the-box'
I worked for years with the late Dave DuBois, whose retirement project was trying to perfect these pumps. He designed the transistor conversion, but found the current through the points was inadequate to clean them. Then he designed his own circuit that used an optical 'chopper' switch; again, my experience was less-than-satisfactory.
On long road trips I carry two spare pumps; I can swap a pump out in 20minutes.
Offline
There may be some leakage past a carb float valve, but that usually results in a flooded engine. The fuel pump has check valves on the inlet and outlet, although they are not called out as such on the diagrams. Debris or a nick in a fuel pump check valve would cause this extra ticking. The solid-state components just change how the pump coil is triggered, it doesn't change how the pump itself works..
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How I found I had a vacuum leak.
I disconnected the fuel line at the carbs and stuck it in a container of gas, like a coffee can, and turned the pump on. If there’s bubbles, you have a suction leak.
I disconnected the fuel line at the carbs and stuck it in a container of gas, like a coffee can, and turned the pump on. If there’s bubbles, you have a suction leak.