Polaris Genesis DI /Virage TXI / FICHT Aftermarket Fuel Pump Issue Discussion Thread

[HiPeRcO]

Lately there has been a lot of reports about so-called "replacement" fuel pumps for the Polaris DI machines. It seems that the experience is consistent that they are not appropriate replacements, in that they draw far more current (>5A) than the OEM (<2A), and create significantly higher pressure.

I am wondering if cutting the voltage applied to the pump would resolve the issue. To this end, below is a DC/DC converter that seems like a good candidate to perform a test with. Who has a "bad" aftermarket pump that wants to do the test? Discuss

https://www.amazon.com/SMAKN-Converter-Power-Supply-Module/dp/B00CXKBJI2

[martincom]

The OEM pump "sound like" and has the shape to indicate it is a motor driven pump. Typically, motors don't start well with low voltage, if at all, don't come up to speed, the windings get hot, the shellac insulating coating melts off, the windings short, and all the white, black & blue magic smoke escapes.

I guess there is a few guys who have purchased the so-called direct replacement pumps that are now paper weights. So I guess they wouldn't be out anything to let you try. I try it with a bench supply before purchasing the DC-DC comverter and see if the pump lives and what the current is reduced to.

[Tune by Tito]

Lately there has been a lot of reports about so-called "replacement" fuel pumps for the Polaris DI machines. It seems that the experience is consistent that they are not appropriate replacements, in that they draw far more current (>5A) than the OEM (<2A), and create significantly higher pressure.

I am wondering if cutting the voltage applied to the pump would resolve the issue. To this end, below is a DC/DC converter that seems like a good candidate to perform a test with. Who has a "bad" aftermarket pump that wants to do the test? Discuss

https://www.amazon.com/SMAKN-Convert.../dp/B00CXKBJI2

"SMAKN Dc/dc Converter 12v Step Down to 5v/3a Power Supply Module"

Will never work!!! is a step down power supply.
You need a step up power supply may be to 14 to 18 volts, higher voltage less amps.
A simple step up power supply is only less than 85% efficient so power will be wasted.
A sophisticated dc-dc step up power supply will need some complex electronics for a 90-95% efficiency.

Here is something can help:

https://www.amazon.com/NW-converter-95Wmax-Supply-Converter/dp/B01E6T7YFY/ref=sr_1_34?ie=UTF8&qid=1500593311&sr=8-34&keywords=12+volt+step+up+converter

However to me the easy way to fix this problem is to find the lower consuming fuel pump in the market(less than 5 amps) and used a relay to power the fuel pump, also a higher capacity Battery will be needed.

Best Regards Tito

[Tune by Tito]

Any way to install a step up controller like those you still need to bypass the fuel pump circuit with a relay, so is activated when you connect the lanyard.

[Tune by Tito]

Here is a better one from 9-14 volts step up to 15volts 10 amps.

https://www.amazon.com/SMAKN-Converter-9-14V-Supply-Module/dp/B00XV8E4IM/ref=sr_1_8?ie=UTF8&qid=1500631204&sr=8-8&keywords=DC%2FDC+step+up+converter+12V+to+14v

With all that current you can power half of Las Vegas.

[HiPeRcO]

The OEM pump "sound like" and has the shape to indicate it is a motor driven pump. Typically, motors don't start well with low voltage, if at all, don't come up to speed, the windings get hot, the shellac insulating coating melts off, the windings short, and all the white, black & blue magic smoke escapes.

I guess there is a few guys who have purchased the so-called direct replacement pumps that are now paper weights. So I guess they wouldn't be out anything to let you try. I try it with a bench supply before purchasing the DC-DC comverter and see if the pump lives and what the current is reduced to.

"SMAKN Dc/dc Converter 12v Step Down to 5v/3a Power Supply Module"

Will never work!!! is a step down power supply.
You need a step up power supply may be to 14 to 18 volts, higher voltage less amps.
A simple step up power supply is only less than 85% efficient so power will be wasted.
A sophisticated dc-dc step up power supply will need some complex electronics for a 90-95% efficiency.

Here is something can help:

https://www.amazon.com/NW-converter-95Wmax-Supply-Converter/dp/B01E6T7YFY/ref=sr_1_34?ie=UTF8&qid=1500593311&sr=8-34&keywords=12+volt+step+up+converter

However to me the easy way to fix this problem is to find the lower consuming fuel pump in the market(less than 5 amps) and used a relay to power the fuel pump, also a higher capacity Battery will be needed.

Best Regards Tito

Fuel pump motors are simple brush motors. The current they draw is a function of their load and applied voltage. Applying more voltage will almost certainly result in MORE current, barring some fluid effects resulting from the pumping portion cavitating, or somesuch. I wouldn't expect that the motor would have any trouble starting with a lower applied voltage, it will just spin slower, draw less current, and produce less fuel pressure.

[K447]

"SMAKN Dc/dc Converter 12v Step Down to 5v/3a Power Supply Module"

Will never work!!! is a step down power supply.
You need a step up power supply may be to 14 to 18 volts, higher voltage less amps.
A simple step up power supply is only less than 85% efficient so power will be wasted.
A sophisticated dc-dc step up power supply will need some complex electronics for a 90-95% efficiency.

Here is something can help:

https://www.amazon.com/NW-converter-95Wmax-Supply-Converter/dp/B01E6T7YFY/ref=sr_1_34?ie=UTF8&qid=1500593311&sr=8-34&keywords=12+volt+step+up+converter

However to me the easy way to fix this problem is to find the lower consuming fuel pump in the market(less than 5 amps) and used a relay to power the fuel pump, also a higher capacity Battery will be needed.

Best Regards Tito

Nope. Not unless the fuel pump is changed to one rated for higher voltage.

Otherwise, apply higher DC voltage to a simple DC motor load will increase the motor current and the operating speed/pressure of the pump motor.

[Tune by Tito]

Fuel pump motors are simple brush motors. The current they draw is a function of their load and applied voltage. Applying more voltage will almost certainly result in MORE current, barring some fluid effects resulting from the pumping portion cavitating, or somesuch. I wouldn't expect that the motor would have any trouble starting with a lower applied voltage, it will just spin slower, draw less current, and produce less fuel pressure.

Will not work with 5 volts, may be 10 volts or 9 volts.

[Tune by Tito]

Nope. Not unless the fuel pump is changed to one rated for higher voltage.

Otherwise, apply higher DC voltage to a simple DC motor load will increase the motor current and the operating speed/pressure of the pump motor.

All fuel pump are rated at 12 volts nominal, however all of them are made to withstand higher voltages, the charging system can dump more than 45 volts to the battery any time.
Also if the flow increase then increasing the load use a external fuel regulator to control the load, this system do not depend on a specific fuel pressure to function correctly, the service manual said between 20 to 30 psi, the amount of fuel injected in the chamber is determine by the stroke of the injector and the fuel maps, is a very basic Alpha Number system with a stupid complex ECU(EMM).

So you will not loose any thing, you only will gain knowledge.

[Tune by Tito]

Here is a fuel pump may work:

https://www.delphi.com/manufacturers/auto/powertrain/fuelhandling/t11

The Delphi T-11 Fuel Pump features low current draw — less than 1.4 amps compared to 6 amps, which is characteristic for automotive fuel pumps — while providing a minimum flow rate of 3 grams⁄second (14.4 liters⁄hour) at 12 V and 250 kPa. The Delphi T-11 Fuel Pump is available with a standard copper commutator, or optional carbon commutator.

Typical Applications
The Delphi-T11 Small Engine Fuel Pump is designed for use in non-automotive small gasoline engine applications such as motorcycles, scooters, small all-terrain vehicles, snowmobiles, personal watercraft and lawn and garden equipment. It can also be used as a transfer pump for automotive auxiliary fuel tanks.

Best Regards Tito.

[bspanovic]

I am almost certain that BLDC motors are used in the in-tank fuel pumps given the no ventilation situation and more importantly hazardous environment where NO SPARKS are wanted, common with brushed DC motors. Brushless motors must have electronic drivers to energize the coils at the right time and the right polarity. The driver must be packaged within our pump housing and is really the best way to control the operation of a BLDC motor. Typically reducing the voltage will reduce its speed of rotation where reducing current will decrease the torque of a motor. Applying excessive voltage for too long above rated specs is NO GOOD as it will increase the speed of rotation and generate heat. The heat is the worst enemy for motors. Applying the under spec voltage should not bother BLDC too much, it will run cooler with slower rotation until voltage drops low for motor to operate and the current will go up again.
So I did some tests with OEM and aftermarket pumps. Bellow is the summary of measurements I took.
Things to note:
-I used water instead of petrol, don't think it would make huge difference on the readings with petrol
-tests were done with approx 2 feet hoses with FPR at the end and schrader valve for my pressure gauge.
-my bench PS was maxing out at just above 14V @ 6A with pump working under load (in the water)
-all readings were taken with pumps under load on my workbench. The extra load and consumption of petrol by fuel injectors should be considered when engine is running.

	Aftermaket				OEM
V	A	psi		V	A	psi
14	5.9	30		14	2.09	23
13.5	5.67	30		13.5	2.03	22.5
13	5.49	29		13	1.98	22
12.5	5.3	29		12.5	1.93	22
12	4.93	28		12	1.9	22
11.5	4.7	27		11.5	1.87	22
11	4.5	26		11	1.85	21.5
10.5	4.32	26		10.5	1.87	21
10	4.1	25		10	1.92	20.5
9.5	3.95	24		9.5
9	3.7	24		9
8.5	3.5	23.5		8.5
8	3.3	23		8
7.5	3.14	22		7.5

The aftermarket pump @7.5V when stalled pushed the pressure to 50psi. When voltage was reduced the current went down as well and vice versa. The same happens when increasing the current ,the voltage would go up as well.
The aftemarket pump was NOT pushing more than 30 psi above 14V up to 18 V being max V applied.
The OEM pump behaved in the same way but the operating range was a lot smaller. Below 10V the pump's motor would stop rotating and current would go upwards.
Temperature was not an issue and the pumps were always running cool as expected being in the water.
For 12L of water to be moved from one to another tank it took:

OEM: 6min 30sec (@13.5V 1.98A 22,5 psi)
Afermarket: 5 min 40sec (@ 8.5V 3.5A 23psi)

For the reference to the non metric people (hate those old school confusing and inaccurate imperial fractions), my Genesis I would use approx 20L per hour when I tow and have an observer on the back seat. When I solo ride at 70% throttle in calm waters my ski uses approx 12L per hour!

It looks that aftermarket pump can be modified by either restricting the voltage or current with the same result. Reducing voltage would be easier but heat, waterproofing and physical mounting need to be worked out.

[Tune by Tito]

This type will be good to look into is the smaller fuel pump I could find that meet the specifications.

http://oem.fuelpumps.com/dodge-fuel-pumps-c-35/dodge-caravangrand-caravanmini-ram-vanroyal-mini-ram-van-fuel-pumps-c-35_250/19871990-dodge-caravangrand-caravanmini-ram-vanroyal-mini-ram-van-fuel-pump-4-cyl-25l-k-efi-p-886.html

The Fuel pump in the Polaris seem to come from a Dodge Ram or Dakota circa 1996!

[K447]

All fuel pump are rated at 12 volts nominal, however all of them are made to withstand higher voltages, the charging system can dump more than 45 volts to the battery any time.

Also if the flow increase then increasing the load use a external fuel regulator to control the load, this system do not depend on a specific fuel pressure to function correctly, the service manual said between 20 to 30 psi, the amount of fuel injected in the chamber is determine by the stroke of the injector and the fuel maps, is a very basic Alpha Number system with a stupid complex ECU(EMM).

So you will not loose any thing, you only will gain knowledge.

The 45 volt system is in no way connected to the 12 volt battery, at all. The 12 volt battery circuit is separate from the 45 volt circuit. They are separate outputs from the EMM.

The maximum voltage on the 12 volt battery during engine run/charging would be just under 15 volts.

You are correct that the Ficht system does not require a specific fuel pressure, just decent pressure within a range. And it requires return fuel flow through the injectors.

On a stock Polaris Ficht watercraft, we can use the measured fuel pressure to verify expected fuel pump operation.

[HiPeRcO]

I am almost certain that BLDC motors are used in the in-tank fuel pumps given the no ventilation situation and more importantly hazardous environment where NO SPARKS are wanted, common with brushed DC motors.

You will be surprised to learn that not only are brushed motors used, but the fuel flows right through the motor (including the brushes)! This is possible because there must be a proper air/fuel ratio for a spark to cause ignition. Pure fuel does not burn, only vapor mixed with air does.

Nice work on the pump current draw measurements! It seems that at least for the pump you have that driving it with 5V may be insufficient.

[martincom]

I did some searching for voltage regulators on Digikey. I was hoping to find something with an 8 volt output and 4.0 amps or more current capability..and in a TO-220 package. I struck out. I found one listed for 5.0 amps in a surface mount package, but it was obsolete and they had no stock.

I'll check Mouser.