The 1975 FJ40, I recently purchased, has a dash mounted push/pull switch that activates an electronic fuel pump. The electric pump runs through the mechanical fuel pump. What is the purpose/reasoning for this set-up?
Electric Fuel Pump
- Thread starter climber33
- Start date
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Downey
SILVER Star
Do you have a rear auxiliary tank, and the elec. pump is being used as a transfer pump ???
Before switching to EFI (Sniper) I had a carburetor and I used a solenoid type electric pump plumbed inline before the mechanical pump. It was a "Facet 40105". I only used it to fill the carb bowl before starting then turned it off. The mechanical pump pulled gas through the turned off electric pump with no problem and the electric pump pushed gas through the mechanical pump just fine with engine off. Maybe that's what your setup is for. Just to fill the carb. With the stock carb that has the sight glass, I could watch the electric pump fill the bowl before starting. This method eliminated a lot of cranking to get a low or empty carb bowl to fill.
A few other notes:
1. A rotary type electric pump didn't work. When off, the mechanical pump can't pull gas through it.
2. I tried the Facet 40105 solenoid type on an 83 2F who's mechanical pump has the 3 ports. The electric pump would push fuel through the 3 port mechanical pump with engine off.
3. I ran the dual pump setup for 20 years on my 74 F.5 with 3 different carbs. It worked great.
4. After 16 years, the first electric pump was still working but started sounding funny so I put a new one on. 4 years later both pumps are gone with the Sniper install.
A few other notes:
1. A rotary type electric pump didn't work. When off, the mechanical pump can't pull gas through it.
2. I tried the Facet 40105 solenoid type on an 83 2F who's mechanical pump has the 3 ports. The electric pump would push fuel through the 3 port mechanical pump with engine off.
3. I ran the dual pump setup for 20 years on my 74 F.5 with 3 different carbs. It worked great.
4. After 16 years, the first electric pump was still working but started sounding funny so I put a new one on. 4 years later both pumps are gone with the Sniper install.
Last edited:
Downey
SILVER Star
So evidently the elec. pump is 15 psi since that is what the tbi requires.
oops! I edited my post above to be more clear.
Downey
SILVER Star
Sniper conversions require more like 40-50 psi, so that is what the elec. fuel pump must be, and the stock fuel pump is just excess baggage.
Yes Jim. The previous electric and mechanical pump that was used with carbs have been removed. The hole left in the block has been blanked off. With the Sniper, I've installed a Walbro GSL 394 electric pump which puts out 62 psi. The Sniper calls for 59 psi.
Downey
SILVER Star
Steamer, 10-4, so there you have it.
Very helpful. Did you just put it on a switch? My stock mechanical fuel pump is not leaking but i suspect it is not oumping hard enough so i am considering adding this one you recommend. Think there would be any issues running it all the time in combination? Thanks!
I only used the electric pump to prime the carb bowl when it sat for some time and would end up empty or low. The pumps are designed to run continuous. They are not that quiet. The only time I ran it full time was when I forgot to turn it off but it bothered nothing.
I do not think adding an electric fuel pump to make up for a faulty mechanical is a good idea. If it truly is faulty, I would be concerned it could fail where fuel enters the crank case. I would replace it with a new, quiet, and very dependable stock Kyosan mechanical pump. I would confirm your suspicions that your mechanical pump is “not pumping hard enough”. What are the symptoms? Is the carb bowl not staying up to mid-level in the carbs sight glass?
Thanks so much for the advice. I am not much of a mechanic but love doing body work on old cars and can turn some wrenches on straight forward jobs. It is running a little hot and running a little lean. I had the carb rebuilt and bought a new brass radiator and it did not help. It likes to be choked about 20%. It also hiccups when i accelerate too fast. I have put my timing gun on it many times and it likes to be set pretty far off from the button. My buddy that knows more than me but not too much thinks it is not getting proper fuel and suggested adding an electric fuel pump. Would love any advice offered. Thanks! I have a 1 F built in Jan 1973.
May I suggest starting your own separate threads. One for your fuel issue and one for the overheating. They may be related but probably not. Title your threads well so that later on others with similar problems can find your threads. Explain your situation with all the facts and as always, pics are a big help and can often eliminate a lot of back forth Q & A to find out things like parts are missing or unusual mods have been made.
