KEMSO Fuel Pump Installation
Fitting a KEMSO 10910 pump into the factory RX-8 fuel-pump module, with Mazda's rules for opening the module and a printed PA11 retaining clip.
This page covers fitting the KEMSO 10910 into the factory fuel-pump module. The pressure figures, the pump resistor and the speed-control relays are on Fuel, ignition and starting.
The pump
| Published item | KEMSO value |
|---|---|
| SKU | 10910 |
| Nominal flow | 340 L/h |
| Flow condition | 43 psi at 13.5 V |
| Published pressure range | 43-90 psi |
| Body diameter | Approximately 38 mm |
KEMSO’s listing makes no Series 1 or Series 2 fitment statement. The 340 L/h figure is a bench point, not in-car delivery at all voltage and pressure states. The RX-8 deliberately runs the pump at reduced voltage at low demand, so validate pressure in both relay states.
Installation
Mazda’s rules for opening the module, from its fuel-pump unit removal page: drain the tank to half full or less on the gauge first, because above about three quarters the fuel level is above the pump flange. The lock ring is tightened with the Mazda SST: one full turn by hand, then a further 50-140° to a torque of 80-135 N·m. If that torque isn’t reached, replace the cap or retainer. Mazda’s leak check afterwards is to start from standstill, or brake five or six times at low speed, and look for leaks.
- Record baseline fuel-line pressure, residual pressure and the fuel-level indication. Relieve pressure, disconnect the battery, ventilate the area and remove the rear seat and the pump service cover. Drain the tank as above.
- Clean the outside of the module before opening it. Mark the lock-ring/module orientation and photograph the sender arm, cup, strainer and wiring.
- Lift the module without bending the sender arm. Drain it into an approved container and compare the KEMSO body, outlet and polarity with the original pump.
- Fit the strainer at the bottom of the reservoir cup in the same low orientation, clear of the cup wall and the sender sweep.
- Use only hose rated for continuous submerged in-tank fuel service, and fuel-injection clamps. General external fuel hose can delaminate when its outer surface is submerged.
- Confirm connector polarity, terminal retention and insulation. Secure the pump without point-loading its body or outlet and make sure the hose cannot kink as the module closes.
- Move the sender through its full travel and check clearance to the pump, retaining clip, strainer, wires and hose. Verify the reservoir-cup fill and jet-pump passages stay unobstructed.
- Fit a sound module seal, return the module to its orientation marks and tighten the lock ring by Mazda’s method above. Reconnect, command the pump and check for vapour and liquid leaks before refitting the cover.
- Recheck the fuel-level indication, running pressure, five-minute residual pressure, connector temperature and pressure in both low and high pump states.
PA11 retaining clip
The custom MJF clip locates the 38 mm KEMSO body in the factory module. It is printed in PA11-HP.
A prototype clip was left immersed in fuel for three weeks. After removal, it retained its apparent structural stiffness and no visible residue was observed in the fuel. This was a useful preliminary compatibility check, but it was not a complete long-term qualification test.
That observation did not measure swelling, mass change, creep or lifetime. On service, inspect contact stress, cracks, softening, wire/outlet damage and sender/cup clearance. A future check should add dimensional and pull testing, vibration/shock exposure and longer-term inspection in the identified pump fuel.
References
Mazda RX-8 2003 workshop manual (European edition), via the foxed.ca mirror, accessed 14 October 2026:
Vendor: KEMSO 10910 product page.
Technical review: