ELECTRIC FUEL PUMP WITH SAFETY PRESSURE SWITCH

[knibusu]

Hey guys I am planning on installing a 12V electric fuel pump with a oil pressure safety switch, reason is for safety, want the fuel pump to cut out if stalls, loses oil pressure, get into acident etc, the gist of it is, when the oil switch sensors pressure the fuel pump will activate on cranking, then when the cars starts on running the fuel pump will run of the ignition on running, I was just trying to confirm what would be the best place to wire from normally open to ignition switch, is ig2 the power to the distrubutor BO and the running state

Holleys Diagram

What I am trying to figure out

Also steps 6 - 9 is from Holley wiring installation.

Any help is appreciated 

This is a photo of the pressure sensor installed on a datsun 240z 

[Banjo]

Nice diagrams !  I'm assuming that this engine has a carby, & is not fuel injected, which use much higher pressure fuel pumps.  There are two types of electric low pressure fuel pumps for carby fuelled engines. There is the electric rotary motor type, which just runs all the time, & there is the diaphram type (like the old British SU fuel pumps), which only power up & pump, when the pressure on the outlet drops.

The most common form of "emergency cut out" switch for electric fuel pumps is an impact type switch. These are usually rated at around 10G force activation, in case of an accident, or collision. Just because a car is in an accident; does not mean that the engine will stop turning. I've seen a crash, where the engine just sat there & screamed; & the only way was to remove a lead from the battery.  The last thing You want in an accident, is to have a fuel pump, continuing to pump fuel onto a hot engine, & creating/causing a fire. 

I'd check the transport website in your area, as to what they stipulate.

Cheers Banjo

 

 

 

Edited Tuesday at 04:36 AM by Banjo

[knibusu]

Yeah its carby, weber 32/36, its just one of those 12v 4 - 7psi fuel pumps

I just want to know which ignition switch wire will have constant 12V when the car is on running, so I assume it would BO as that is also connected to dizzy I believe and this will supply my 12V to run the fuel pump when car is on running, and if ever the oil pressure safety switch sensors pressure below 5psi it will shut the fuel pump off.

[altezzaclub]

Yes, BO before it goes through the ballast resistor.

[Banjo]

I really think there is something wrong with the circuit above, or the logic of operation.  Did You obtain this circuit from this website link below ?

https://www.jalopyjournal.com/forum/threads/oil-pressure-safety-switch-wiring-help.1112142/

Further down the page a relay is incorporated.  I'll have a think about this.

Is your purpose for fitting it, to not allow the engine to fire up, until the oil pressure during cranking, is enough to prevent a "dry cranking" situation.

The needle valve in any carburetor usually stops any fuel from entering the carby, once the fuel bowl is full. The needle valve simply opens & lets more fuel in, once the fuel level in the carby bowel lowers slightly.  This action keeps the fuel bowl constantly full, & to a certain level.  Most engine regimes don't turn an electric fuel pump off.

Are you trying to "stop the engine from starting", until the starter motor cranking, has built up some oil pressure ?  As stated earlier, if You want to set this up as an accident scenario, where the fuel pump stops, on impact; then You need a G force sensor on impact switch, to turn the fuel pump off.

I'll come back to You tomorrow, after I have a think about the logic behind this. I can see some need for an arrangement like this, in maybe a racing car; but not a road car.

Cheers Banjo 

 

Edited Tuesday at 12:58 PM by Banjo

[knibusu]

Sorry I should of stated the purpose, I am getting rid of the mechanical fuel pump and wanting to install the electric fuel pump, so my Idea on the oil pressure safety switch is, when the car is cranking gets 5 psi oil pressure the O.P.S.S will sense oil pressure and turn the fuel pump on, then when the car starts it will run off 12 volts on running. The only reason I am using the O.P.S.S in case my car dies such as stall the car while driving, lose oil pressure, crash worse case scenario, the fuel pump is not constantly on and pumping fuel.

Yes I know you can do it with the relay setup and I was considering that 

https://www.hotrod.com/how-to/safe-and-efficient-electric-fuel-pump-wiring

But the O.P.S.S is different PSI this switch operates at 7 PSI, three terminals S, I, P

 

The holley switch operates at 5 PSI, three terminals N(normally closed), NO(normally open), C

And the stock KE70 operates at 0.4 bar, so the holley is better in that way,

I guess really all that means is the car will shut off quicker if it senses low oil pressure if you use the S,I, P switch.

and with the three different terminals I think you have a different wiring setup. 

Also Banjo I think you are also correct, I forgot to mention this is also another way Holley says you can wire the Holley Oil Pressure Safety Switch. They just didnt give specifics on the relay so I opted for the easy route the one without the relay. 

Yeah the only reason why I am wanting to hook it up like this is just safety I could just get the fuel pump, and positive from pump to ignition on running source with inline fuse, and earth from fuel pump to body chassis and be done with it but that would mean as soon as I get 12V the pump is pumping so, like if my car is in on position but not running the pump would be pumping fuel still, the idea of the Oil Pressure Safety Switch is just safety and peace of mind for me, knowing that the fuel pump will be only on when the car is cranking and car running engine running.

 

 

 

Edited Tuesday at 01:42 PM by knibusu
extra photo

[knibusu]

So after some further investigation I have found what I am looking for two ways to do it with or without relay and this diagram shows with a relay and what wires go to the relay. 

 

 

 

 

So basically the below diagram is the completed wiring and setup BO, will be the best 12 volt source for me and should work like I want it, I will probably set it up with a relay probably the safest option a bit more wiring involved but thats okay I will let you know how the setup goes.

[Banjo]

The more I think about this technique, the more questions it raises, in my mind.  The motor racing industry, may well require such a device, but for a normal road car, the implications of low or lack of oil pressure, whilst driving, & the engine just shutting itself off, outside of your control; could be extremely dangerous.

The oil safety light on the dash of most cars is really all that You require.  Have a read of the comments at this link.

https://classicbroncos.com/forums/threads/wiring-electic-fuel-pump.43215/

When you first turn the ignition key "On"; before trying to start the car, the dash oil pressure warning light comes on, which tells you, "that the oil press sensor is working". When you start the engine & the oil pressure is generated, the warning light goes out; & You definitely know that the oil pressure is present & working OK.

I suggest, that if You are concerned, or interested about oil pressure, in your engine; that You fit an oil pressure guage, to your dash area.  You will learn more about oil pressure watching that over time.

I simply think, that providing your car & engine, the ability to shut down the engine, whilst You are driving; "outside your control", could be downright dangerous.

eg:  You are highway driving, at say 100 klm/hr. Your oil level in the engine, is a bit on the low side. You approach a big curve in the road, & the sideward force moves the oil in the sump, sideways; & the intake pickup for the oil pump, grabs some air, as it is now not totally covered with oil. An instantaneous switching of your oil pressure safety switch, turns the engine off. You are on a curve, at elevated speed. The possible ramifications could well prove fatal, if You lose control.

I could not imagine a rally drivers, ever considering fitting such a protection device to their engine.  That engine gives one cough, whilst drifting sideways with opposite lock, on a dirt road, among the trees, is a complete "no no" to my mind. 

I'm open to others point of view, but personally, I do not think, it is a useful addition, to your road car. 

P.S.  When assembling a fully reconditioned engine, all the bearing areas, are "assembled wet", with oil. The engine may also be turned over by the starter motor, without spark plugs or ignition connected, so all oilways in the block & head are filled.  The only other situation, I can imagine, which might require such an action; is if an engine has been sitting for years, & is being started for the first time. Remove the plugs & turn the engine over, on the starter motor, is a common precaution.

On top of that the Facet electric fuel pump, is a fairly expensive & highly sophisticated fuel pump, which is self adjusting, & provides a constant pressure, according to the maufacturers description.

Quote

Facet Cube Solid State Fuel Pump Kit (12V)

Facet Cube Solid State Electronic Fuel Pumps are the best solid-state technology available for OE and Aftermarket applications. With thousands of successful applications and millions of pumps sold worldwide.

Features:

• Transient protection
• Sealed electronics
• ELV compliant
• Ground positive or negative
• Reverse polarity protection
• 1.4 amp average current
• Self-regulating pressure
• Compatible with gasoline, diesel, biodiesel, E85, blended alcohol and fuel additives

A dependable fuel pump is the beating heart of your engines fuel system and a Facet fuel pump provides the reliable fuel supply your vehicle needs. Operating for over 70 years has seen the Motor Components brand develop a Facet replacement fuel pump for literally every application whether that be automotive, agriculture, marine or power sport. Available in 12V and 24V configurations and designed and tested to withstand harsh environments and tough conditions ensures you have the high quality and robust construction needed for consistent fuel pressure and flow from start up to shutdown.

The range of Facet fuel pumps include:

 

• Facet Gold-Flo Fuel Pump - Featuring solid state circuitry and compatible with all fuel types make these easy to install pumps meet or exceed all performance specifications
• Facet Cube Fuel Pump - No electrical contacts, bearings or diaphragms to wear out make these units last four to five times longer than other electric fuel pumps.
• Facet Posi-Flow Fuel Pump - Features 2 bolt installation for quick fitment and no electrical contacts, bearings or diaphragms to wear out.
• Facet Dura-Lift Fuel Pump - Rated for all fuel types, these self priming pumps are designed for industrial applications and other heavy duty machines.

Some signs that your fuel pump might be in need of replacement include: hard starting, engine sputtering, stalling or surging and excessive noise from the fuel pump unit. When fitting a brand new fuel pump, we also recommend fitting a replacement fuel filter and running a fuel system cleaner for a quick and easy fuel system overhaul, allowing you to get the most out of your brand new pump. To shop our whole range of fuel, ignition and exhaust parts, visit the website today or head into your local Repco store and speak with one our friendly staff.

 

 

 

Would like to hear others thoughts on this matter.

P.S.  As a matter of interest; where did you mount the Facet Electronic fuel pump ?  Is it in the boot area, adjacent to the fuel tank, or up in the engine bay somewhere, close to the engine proper ?

P.S.S.

Is this a transducer for an oil pressure guage ?

Cheers Banjo

Edited Wednesday at 01:51 AM by Banjo

[altezzaclub]

"You approach a big curve in the road, & the sideward force moves the oil in the sump, sideways; & the intake pickup for the oil pump, grabs some air, as it is now not totally covered with oil. An instantaneous switching of your oil pressure safety switch, turns the engine off."

Actually, a hesitation, hardly noticeable but Josh picked it up in the Evo5 at the Night Tarmac Sprints in Sydney. Luckily Steve the tuner was there that night and stuck his laptop on the roof and went through the data. He expanded a few traces to milliseconds and found the oil pressure had a hiccup on some corners, and as the safety cutout was set to 48psi it cut the ignition for a cylinder or so.

Its still a good idea for an accident, like the dual relay cutouts for fuel pumps in injected cars, you have to have the fuel pumps turn off when the engine stops, even with the ignition on. That was in the COR box I fitted with the 4AGE and factory loom, and now the Haltech incorporates that feature in itself.

That wiring diagram looks good, it has everything you need.

[Banjo]

Don't forget, that our friend here (Knibusu), does not have fuel injection. His car has a simple carby.  These type of 12V fuel pumps only typically produce 4-6 PSI.  They are however, much better at "pushing fuel" than sucking/drawing it; which is a good reason to locate the pump, in the boot area, close to the fuel tank.

However, this "Facet" brand pump, is not a cheap pump; & is quite sophistcated.  Apparently, as soon as there is sufficient back pressure it turns itself off, or reduces it's output, according to this discussion I found on the web, at the link below.  I know even the early SU fuel pumps used to basically turn off, or reduce the flow, as my Dad had an early Morris straight 6 (like the Worsley 6/80), & the SU fuel pump was on the passengers side on the rear of the engine bay, & you could hear it ticking away, & changing it's beat.

The SUs were not very good at sucking either. I think on the very first Minis, the SU was up front; but later Minis, had the SU, right at the rear, near the tank.

https://www.4x4community.co.za/forum/showthread.php/19591-Facet-electric-pumps-Fuel-return

Cheers Banjo

[knibusu]

So the oil pressure switch is basically acting as a fuel cut solenoid, everything is still stock, I am still using the stock KE70 oil pressure sensor, the stock oil pressure sensor of the KE70 is 0.4 bar

The ke70 oil pressure switch is rated almost the same oil pressure as the Holley oil pressure safety switch, so there is no way for the holley oil pressure safety switch to cut off the car while driving, because its acting on the stock KE70 oil pressure sensor. The holley switch is not shutting off the car loses oil pressure its shutting off the fuel pump, so as soon as the car dies the fuel pump dies at the same time. 

The orange arrow arrow the thing that its pointing to is the Datsun 240Z stock oil pressure sensor. the T piece is used for both stock oil pressure sensor and holley oil safety switch to get pressure, its just a way to join the two pressure switches. 

So as for the KE70 where the orange arrow is pointing the stock KE70 oil pressure sensor will go. Its not a full blown EFI system, the stock mechanical pump runs 4 - 7 psi, I am essentially removing and blocking it off, and running the Electric Fuel Pump then running the pump as close to the fuel tank as possible on the chassis rail, it will pump the fuel from the tank then use a bypass fuel pressure regulator to regulate the fuel set at 4.5 psi, weber usually says 3 psi, but lowest pressure regulator is 4.5 psi as affordable price. then goes to the carby.

Try not to think of the Holley pressure safety switch as a oil pressure switch, its like a hobbs switch, if it sensors the correct stock ke70 oil pressure from the car it will turn the fuel pump on when car is running and when the ke70 oil pressure sensor senses 5 or below psi the fuel pump will shut off, in no way can it turn my car off because the stock ke70 oil pressure sensor is plugged into the t piece as long as the ke70 oil pressure sensor senses above 5 psi the fuel pump will be on, if the car hits 5 or drops below 5 psi both the car will bog out and stall, the fuel pump will turn off because it has lossed oil pressure, the holley pressure safety switch can't turn the car off from loss of oil pressure it only can shut off the fuel pump from loss of oil pressure. Its kind of a weird thing that not many people do because its easier just to have the pump run when the car is ignition on 12v but if you were to stall your car and the ignition is still in on position the fuel pump will still be pumping fuel and running, my ke70 is manual, so example if you are driving the ke70 and you hit a lightpost and pass out, the car will still be ignition on pumping fuel because you havent switch from ignition on to lock, but if you hook up the holley pressure safety switch if you hit the lightpost and pass out you would hopefully take your foot off the clutch drops to 5 psi oil pressure stalls out the engine and the fuel pump will cut off.

Even more simpler the cluster stock oil pressure light as long as that is not on the fuel pump will be pumping when you turn off the car or lose oil pressure and the oil light comes on the fuel pump will be off.

 

Edited Wednesday at 10:43 AM by knibusu
misclick

[knibusu]

At a cost perspective yeah it might be better to just run a mechanical fuel pump, but ive gone through three mechanical fuel pumps within the year, always the same thing the diaphragm giving out and puncturing and fuel pump leaking.

Any they are not cheap either 

Both goss and fuelmiser I have used and they have both failed.

So the thought of running the electric fuel pump tempted me. Yes you might spend a little bit to set it up but the advantages are there.

This is the electric fuel pump I'm going with its a aeroflow electric fuel pump adjustable from 4.5 to 7 psi

[Banjo]

Quote

but ive gone through three mechanical fuel pumps within the year, always the same thing the diaphragm giving out and puncturing and fuel pump leaking.

No, No, No !  New mechanical fuel pumps do not fail like that, or so quickly.  I think I know what is your problem ?  Not supplied with any of the new mechanical fuel pumps You have purchased in the past, is a fibre spacer, about 12mm think, that fits between the fuel pump flange, & the side of the engine block, where the pump fits. If you omit this spacer, the fuel pump arm is "too close" to the offset lobe on the camshaft, that operates the mechanical fuel pump. This means the diaphram in the pump travels too far up, & either tears the diaphram, or breaks the pump.

Put the spacer back in, & your mechanical fuel pump issues will disappear, immediately.

Some lots of replacement K Series replacement pumps are sold with two (2) off gaskets.  They are not being generous.  The two gaskets are for fitting to both sides of the spacer block.  I've even seen one pump advertised, which includes the spacer block.

Guaranteed to solve your problem !

Cheers Banjo

Edited Wednesday at 12:13 PM by Banjo

[knibusu]

Yeah every single pump I got came with the spacer and two gaskets. I keep the spacer and gaskets as spares now 😆, but yeah I don't know, I'm gonna try the electric fuel pump setup and see how I go.

Also I had a look at my ignition switch and tested each terminal with a multimeter to test for 12V source
I am a bit of a visual learner so looking at the wiring diagram I understand it a little bit but actually seeing the circuit and testing gave me a better understanding 

 

Ill let you guys now how I go with the installation and keep you posted. 🤙. I also have a immobiliser in my and the previous owner ran it off ST2 seeing that and testing voltage when immobiliser is on and off was interesting to. 

[Banjo]

Quote

but ive gone through three mechanical fuel pumps within the year, always the same thing the diaphragm giving out and puncturing and fuel pump leaking.

I'm intrigued now; as to why all three (3) brand new mechanical fuel pumps, mechanically failed; all with damaged diaphrams, in a short period of time; when You had utilised the spacer block to mount them off the engine block mounting point ?

The only thing I could suggest; was that the curved arm on the aftermarket ones, was a different shape or profile, to the Toyota original supplied & fitted pump ?

My KE30 with a 4K-U engine has been running a mechanical pump for 20 years, I've owned it, without issues. They are not real good at drawing/sucking, without priming; but once that line has got fuel in it, they never stop or fail; from my experience.   

Got me beat !

However, I applaud your determination to fit a good electric fuel pump, in the boot area, close to petrol tank.  It is the way to go.

P.S.  In a petrol / carby engine, the fuel pump is one item, you can actually drive, without using one at all.  Many years ago, in an olde English car, the S.U. fuel pump failed, in the middle of no where. A small plastic jerry can, was roped to the roof rack, & a plastic tube run from said plastic jerry can, to the carby fuel inlet. A quick suck on the tube to get the fuel running down the plastic hose, & we drove all the way from Brisbane to Sydney, without so much as a hiccup !    I think it is referred to, as "gravity feed".  True story.

Cheers Banjo

 

 

Edited yesterday at 01:46 AM by Banjo