C44 Fuel Pump Kit, (RXP255E2) HD
C44 Fuel Pump Kit, (RXP255E2) HD
C4 Corvette Fuel Pump Kit — RXP255E2 HD
A Racetronix RXP 255 LPH pump, the hardware to mount it on the hanger, and a complete HD wiring system from the battery to the pump terminals. For 1989–1996 Corvette.
Kit RFPK-044 | RXP255E2 | PIK-C4X | FPWH-044HD | IPH-3W12 | BCA-4W | ITWH-042
This is the complete package: pump, pump installation hardware and wiring, under one part number. Everything between the battery and the pump is either supplied new or deliberately left to do a lighter job, so the pump you are paying for actually gets the voltage it needs.
Most pump upgrades change the pump and leave the wiring alone, or add a relay kit that stops at the tank. Either way, the current still has to pass through the factory hanger connector, the factory pass-through and the thin factory pump leads — wiring sized for the original pump, and often decades old. A high-output pump on that wiring runs short of voltage at best, and at worst overheats the bulkhead and connectors.
The wiring side of this kit is built in two halves. Forward of the hanger it adds a new circuit alongside the factory one: a 10 gauge fused feed taken straight from the battery and switched by a heavy-duty relay. The factory pump circuit stays intact and must remain functional, because that is what triggers the relay — your car keeps full control of the pump, including prime and oil pressure safety logic. From the hanger back, it is a clean replacement: output connector, bulkhead, in-tank wiring and pump grounds are all new and sized for a modern high-output pump.
Already have a pump? Order the matching FPWK wiring kit instead — it is this same wiring system without the pump and pump installation kit. See Which kit do I need? below.
Why the wiring matters
Fuel pump output is a direct function of supply voltage. A pump running a volt or more below battery voltage will not deliver its published flow, and on a boosted or heavily modified engine that shortfall shows up as a lean condition exactly when you can least afford one.
On a C4, voltage is lost in stages: long small-gauge chassis runs, the factory relay and fuse block, the hanger connector, and finally the thin pump leads inside the tank. Each stage is small on its own. Added together, and loaded with a high-output pump drawing several times what the original unit drew, they add up to real pressure loss.
- Full battery voltage at the pump terminals under load
- Factory wiring removed from the current path, front and rear
- Its own fuse, independent of the factory fuse block
- Factory pump control logic untouched — no safety circuits bypassed
What's in the kit
| Part | Description | Qty |
|---|---|---|
| RXP255E2 | Racetronix 255 LPH in-tank fuel pump, high pressure/volume, E85 compatible | 1 |
| PIK-C4X | C4 fuel pump installation kit (contents below) | 1 |
| FPWH-044HD | C43/C44 fuel pump wiring harness HD — relay, fuse holder, 10 gauge feed | 1 |
| IPH-3W12 | Intermediate pump harness, 12" | 1 |
| BCA-4W | Fuel-safe bulkhead connector assembly, four-way | 1 |
| ITWH-042 | In-tank pump harness HD, 12", open-style pump connector | 1 |
| BGC-8 | Body ground cable, 8 gauge, 3/8" terminal, 8" | 1 |
| GMBT-B | GM battery terminal for 3/8" ring terminals | 2 |
| PBIC-001 | Pump booster interface connector set | 1 |
| BCN-R / BCN-B | Insulated nylon butt connectors, 22–18 and 16–14 gauge | 1 each |
| — | 25A and 30A ATC fuses with spares, and fuse holder rating labels | — |
PIK-C4X pump installation kit
- C4 fuel sender gasket, plus a gasket hardware kit of screws with bonded sealing washers and O-rings
- Pump inlet filter sock
- Rubber pump mount grommet
- 5/16" ID submersible fuel hose, SAE 30R10, 130 mm (5") length, with two stainless steel hose clamps
- Foam insulating sleeve for the pump body
The hanger gasket and sealing hardware are replaced because the hanger has to come out for this installation anyway, and a used gasket is not worth reusing on a tank you have just opened.
The pump: RXP255E2
The RXP255E2 is a 255 LPH turbine pump from our own RXP range, built for high pressure and volume and compatible with E85. Turbine pumps run quieter than older roller-vane designs and tolerate ethanol blends better.
It uses the standard open-style pump connector, and the ITWH-042 in-tank harness in this kit mates with it directly — nothing is cut, spliced or soldered inside the tank. The pump is supplied matched to the wiring, so there is no connector to identify and no chance of ordering the wrong in-tank harness.
What each part of the wiring does
The wiring is a system. Each piece exists because the piece it replaces could not carry the current, seal against fuel, or both.
FPWH-044HD — main wiring harness
Battery to the rear of the car
Carries a 10 gauge feed from the battery ring terminal through a sealed 630-series ATC fuse holder, into a 630-series sealed relay with an integral suppression device, and on to the rear of the car in 10 gauge. The factory fuel pump feed plugs into the input side of this harness and does one job: energise the relay coil.
The output is a three-position Metri-Pack 280 connector rated for 30 amps. This is deliberately not the factory hanger connector. The original Weather Pack connector and its terminals were never intended for this kind of current, so the kit supplies its own mating half rather than plugging into one that would become the new weak point.
IPH-3W12 — intermediate pump harness
Harness output to the hanger, outside the tank
The 10 gauge feed arriving from the relay is split inside the IPH into two bonded 14 gauge conductors, both of which pass through the bulkhead and are recombined on the other side. The pair shares the load in parallel and carries 28 amps combined — this is not a step down to a single smaller wire.
It is also where the high-current pump ground is brought back into the circuit. The ground ring terminal on top of the hanger connects into the IPH, where it is bonded to a 10 gauge conductor that carries it forward to a spiked chassis ring terminal at the relay end.
BCA-4W — fuel-safe bulkhead connector assembly
Through the hanger plate
A four-way sealed bulkhead that carries both positive conductors, the low-current ground and the level sender signal through the hanger plate. It seals on the liquid side and the vapour side, replacing the factory pass-through — the part we see fail most often when a high-output pump is run on factory wiring.
ITWH-042 — in-tank pump harness
Bulkhead to the pump, inside the tank
Picks up the two positive conductors on the inside of the bulkhead and recombines them into a single feed at the pump, terminating in the open-style connector that plugs straight onto the RXP255E2. A separate heavy-gauge conductor runs from the pump connector to a ring terminal on the brass bolt through the hanger, forming the high-current ground return.
Built with PTFE or ETFE insulated wire rated to 600 volts — the same wire we use in every in-tank harness we make. It will not swell, harden or leach in gasoline, ethanol blends or methanol. It also carries a flying lead for the fuel level sender, so your factory sender wire joins our harness and its signal passes through the bulkhead to the gauge unchanged.
Fuses, labels and connectors
Supplied in the accessory bag
We no longer ship the fuse holder with a rating printed on it. The kit includes both 25 amp and 30 amp ATC fuses with spares, plus labels so you can mark the holder to match the fuse you actually fit. Insulated butt connectors are included for the small number of joints made to vehicle wiring.
Two grounds, not one
Grounding is where most pump upgrades quietly fail. A pump that cannot get its current back to the chassis is just as starved as one that cannot get current in, and the factory hanger ground path was sized for the original pump.
| High-current ground | Heavy-gauge PTFE conductor from the pump connector to a ring terminal on the brass bolt through the hanger. On top of the hanger a second ring terminal picks it up into the IPH, where it bonds to a 10 gauge conductor running forward to a spiked chassis ring terminal at the relay. |
|---|---|
| Low-current ground | Carried through the BCA-4W bulkhead alongside the positive conductors and the sender signal, in parallel with the high-current path. |
Follow the grounding instructions exactly. An incomplete ground, or an assumption that the factory ground path still applies, is the single most common cause of a kit that does not perform as expected.
The current path, end to end
| Battery ? fuse ? relay | 10 gauge, sealed 630-series ATC fuse holder, 25A or 30A fuse |
|---|---|
| Relay | 630-series sealed relay, triggered by the factory pump feed |
| Relay ? hanger | 10 gauge to a three-position Metri-Pack 280 output, rated 30A |
| Hanger, outside | IPH-3W12 — 10 gauge split into two bonded 14 gauge conductors, 28A combined; high-current ground bonded and carried forward |
| Through the plate | BCA-4W sealed four-way bulkhead, plus the brass bolt for the high-current ground |
| Hanger, inside | ITWH-042 — conductors recombined, heavy-gauge ground to the brass bolt, sender pass-through |
| Pump | RXP255E2, plugged directly onto the ITWH-042 connector — no splices, no solder |
Engineering specifications
| Pump | Racetronix RXP255E2, 255 LPH turbine, E85 compatible |
|---|---|
| Relay | 630-series, sealed, integral EMI suppression |
| Relay socket | 630-series, push-to-seat |
| Fuse holder | 630-series ATC, sealed, supplied unlabelled |
| Fuses supplied | 25A and 30A ATC, plus spares and rating labels |
| Main power feed | 10 gauge — battery ring terminal to fuse holder, fuse holder to relay, relay to harness output |
| Bulkhead pass-through | Two 14 gauge conductors in parallel, 28A combined |
| Ground return | 10 gauge to the hanger, heavy-gauge PTFE inside the tank |
| Harness output connector | Metri-Pack 280, three-position, 30A rated |
| Pump connector | Open-style, matched to the RXP255E2 |
| In-tank wire | PTFE / ETFE insulated, 600V rated, submersible |
| Bulkhead | BCA-4W, four-way, sealed liquid and vapour side |
| Pump hose | 5/16" ID submersible, SAE 30R10 |
| Splices | Ultrasonically welded — no solder joints |
Which kit do I need?
The C4 range is split two ways: by model year, because 1984–1988 and 1989–1996 cars use different hanger connectors, and by whether you need a pump.
| Your situation | 1984–1988 | 1989–1996 |
|---|---|---|
| Want the complete kit with a Racetronix RXP255E2 pump | RFPK-043 | RFPK-044 |
| Already have a Walbro 255/350 or Racetronix RXP pump | FPWK-043W | FPWK-044W |
| Already have a Walbro 450/525 or other pump with 280-series leads | FPWK-043D | FPWK-044D |
None of these kits support the factory Delphi pump. The FPWH-044HD harness is not sold on its own — the factory bulkhead and in-tank wiring cannot carry the current a modern high-output pump draws, so we supply the complete current path or nothing.
Not sure which kit you need? Email [email protected] before ordering.
Fitment
Vehicle: 1989–1996 Chevrolet Corvette with the four-position Weather Pack hanger connector. Single-pump cars only — the ZR-1 runs twin in-tank pumps and is not supported by this kit.
1984–1988 cars: These use the three-position hanger connector and need the adapter supplied in RFPK-043 — order that kit instead.
Installation notes
- The fuel pump hanger must come out to fit the pump, the bulkhead connector, the ground bolt and the in-tank harness. Tank lowering, hanger removal and fuel pressure relief are outside the scope of our instructions — follow the factory service manual or an equivalent repair manual for your car.
- Read the grommet warning label in the pump installation kit before fitting the rubber pump mount.
- The bulkhead connector and the ground bolt install through the hanger plate and require drilling. Hole sizes and locations are given in the installation manual.
- Fit the fuse specified in the manual, and apply the matching label to the fuse holder so the next person to open it knows what is in there.
- Work with the battery disconnected and observe normal fuel system safety precautions.
Frequently asked questions
I already have a pump. Do I have to buy this kit?
No. The FPWK wiring kits are the same wiring system without the pump and pump installation kit — see Which kit do I need? above.
Why can't I buy just the relay harness?
Because the relay harness only fixes the front half of the problem. The factory hanger connector, pass-through and in-tank wiring become the bottleneck the moment the front half is fixed, and with a high-output pump they are what overheats and fails. We supply the whole current path so the kit works as designed.
Does my factory fuel pump circuit still need to work?
Yes, and that is by design. The factory circuit triggers our relay, so the factory fuse, relay and wiring must all be functional. If your car has an existing fault in that circuit, fix it first — this kit will not mask it.
Does the fuel level gauge still work?
Yes. The in-tank harness has a flying lead for your factory sender wire, and the signal passes through the bulkhead to the factory circuit unchanged.
Will it fit an aftermarket hanger?
The in-tank harness is built to accommodate the common sender variations — wire-wound or ceramic card level sensors, and push-on or riveted sender connections. If your hanger differs from the factory design in other ways, email [email protected] before ordering.
I have a question before I order.
Email [email protected]. Our support forum is reserved for customers and access is granted after purchase.
Warranty and technical support
Racetronix products are warranted against defects in materials and workmanship. Technical support is provided to verified customers through our support forum only — we do not provide technical support by phone or email.
Request forum access when you place your order so your account is approved before your parts arrive. Presale questions go to [email protected].
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Designed, built and tested by Racetronix in Markham, Ontario, Canada.
