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WALBRO 255 FUEL PUMP UPGRADE - MAZDA RX8 2003-2008 HONDA TOYOTA SUBARU
any idea is this legit to install 2004 s1?
I`m thinking my fuel pump has some problems..
Thanks!
If you look back into fuel pump failure threads you will see much discussion about the walbro pumps and other solutions. Some have found success with the Walbro pumps, others have found solution with installing a Series 2 fuel pump (with slight modification to the intake line and electrical connector). All DIY's are posted here within the fuel pump threads if you search it. Best to you.
Last edited by gwilliams6; 01-29-2016 at 10:33 PM.
Be advised that the current Mazda recall 1017E is vague. While it reads,"...will replace the fuel pump filter body w/ a modified one to address...1017E.", in reality Mazda will swap out the entire filter body AND pump assembly for a completely new filter body and pump assembly. So, if you're running an aftermarket pump, it will go too. I intend to swap in my OEM pump, let Mazda perform 1017E, then replace my DW200.
Be advised that the current Mazda recall 1017E is a vague. While it reads,"...will replace the fuel pump filter body w/ a modified one to address...1017E.", in reality Mazda will swap out the entire filter body AND pump assembly for a completely new assembly. So, if you're running an aftermarket pump, it will go too. I intend to swap in my OEM pump, let Mazda perform 1017E, then replace my DW200.
Can you link to any evidence that Mazda are replacing entire fuel pump assemblies?
Guys, As I indicated in my post...no there is no documentation / evidence that Mazda is replacing the fuel pump as well. That's why I posted. But having installed a DW200 in my car I was adamant at the dealership today inquiring if it w/b removed OR swapped into the new assembly. I was taken back to the mechanic who physically showed me that "the entire filter body assembly (w/ the fuel pump)" w/b replaced. So, I recommend that you confirm w/ your dealership, but at mine they are NOT swapping my existing fuel pump into the new assembly. Wish they were.
Just documenting the detailed S2 pump information here in the link below including formal flow/pressure testing with both the factory Denso pump and the Deatschwerks DW65C (rated 265 lph) along with many pictures of the internals
Just wanted to post about my recent fuel pump issues in the hopes that it might help others here.
2005 RX8, 110k kms, mostly stock. I think I was running on the factory fuel pump.
Late last summer, the car started hesitating and jerking quite badly at around 6-7000rpm when at WOT, eventually registered a misfire when I really pushed it. Otherwise, the car felt fine and if throttle was applied gradually it seemed ok. Pulled the cat which was only about a year old and it looked fine. Cleaned the MAF and ESS, reset the ECU, and thought this had solved the issue.
Winter came shortly afterwards and the car drove fine throughout the Canadian winter, but there are obviously less opportunities for WOT when the roads are covered in ice/snow. Unfortunately, once the hot weather came back in the spring, I noticed the same high rpm hesitation as last summer. Decided to try really pushing it about 30 minutes into my drive and all of a sudden the hesitation started occurring at all rpms. It would still idle fine but once throttle was applied, the car would quickly die. Once dead, it wouldn't start again until maybe 5 minutes later. Suspected the fuel pump was on it's way out so I decided to just replace it with the Carter fuel pump. I guess the cold weather was able to prevent the fuel pump from overheating.
Being impatient when removing the pump, I decided to try to fabricate a fuel pump ring removal tool out of scrap metal brackets and bolts. Needed to use a grinder and welder, but it worked!
The new fuel pump has been in for about a week and the car feels totally different when driven aggressively. I can go WOT up to redline without any issues and it seems the gradual loss of power was slow enough for me to not really notice it.
I had the common symptoms often found here on this forum and other threads, you know, no power, poor acceleration, usually when weather is warmer, but not always, code reading says secondary air pump, so frustrating ! Well if you read as many posts on these as I have, you will probably end up just as confused and annoyed as I was. Change this, check that, a list as long as your arm and very expensive " check list " cause honestly, that all it is. I CHANGED the CAT, FUEL PUMP, PLUGS, LEADS, COILS, INJECTORS, cleaned lines, all made a difference, and each time I did one of these things the problem went away ! FOR A SHORT TIME! Then came back after 1, 2 or 3 weeks, by the time I had done all these things over a year or so, no crap it would have been better to put a load of cash inside the car and just set fire to it, was over it ! The reason I am commenting on this particular thread is simple, he's right, yes they do have pump problems, and Bravo to him for posting his solution, absolute champion, without it I would not have found the ACTUALL problem ! After all the frustration, expense I found a problem with the design of the pump, and deeerrrr explains everything. FUEL PRESSURE RELIEF VALVE. If this fails the fuel pressure will drop dramatically, hence minimal amount of fuel being injected, so more accelerator, more air, mixture wrong, no power, can't climb the slightest incline ! I find it absolutely mind boggling that such a simple design fault could destroy the reputation of such a fabulous car ( when running properly ) and ended the RX ! So here it is in a nut shell, geniuses at the design desk needed a way to get the fuel from right side of tank to left evenly and efficiently, so in the housing they incorporated a syphon, to ensure the line stays full it is incorporated into the pressure relief, return, rubber block is at the bottom of tank, WITHOUT ANY FILTER, so can pick up any rubbish in tank, ( even from new can get fine particles in tank, and the more fuel you put in, the more crap you put in ) this then gets sucked up to the valve, which stays open, no pressure to main line, this can then clear and pressure returns, making it a random problem, frustrating hey ! Clean thoroughly the pump housing and blow out all valves, reassemble then wrap in fine nylon stockings doubled, zip tie at top so top flange seal is clear, replace ! Do coils every 100k, happy RX8ing
I've gone through a Walbro and now a DW200 and still the same problems.
THE DIFINITIVE FIX FOR FUEL CUT ON HIGH G LEFTS AND ANY RANDOM LOSS OF FUEL PRESSURE IN A LOWER END HP BOOSTED, STREET, LIGHT TRACK DUTY CAR IS TO ONLY USE A BRAND NEW SLIGHTLY MODDED TO FIT SERIES 2 FUEL PUMP ASSEMBLY.
DO NOT PUT HIGH FLOW PUMPS IN A SERIES 1 ASSEMBLY IT DOES NOT WORK. I HAVE DONE IT TWICE NOW AND IT STILL DOESN'T WORK!
SERIES 2 OEM Fuel Pump Assembly part no. N3R1-13-35Z Some Modifications to fit in a Series 1 fuel tank is required.
End of Scottish quotes in 2014.
.................................................. .................................................. .................................................. .................................................. .................................................. .
This thread is intended to answer some questions about the function (or lack thereof) of the OE RX-8 fuel pump assembly as it is employed on the 2008 and earlier models.
There is a lot of speculation out there about pump efficacy, volume and the function of the siphon system for the saddle-style fuel tank as well as some pretty wild conjecture about the filtration parts, pressure regulation and the control electronics.
The fuel pump assembly is located under an access panel beneath the left-side rear passenger seat. The lower seat cushion simply pulls up and the panel beneath is held in place by 4 sheet metal screws. Since the pump is a "dead-end" style, self-regulating assembly, there is only a single discharge outlet and no return inlet. There is a single electrical connector on the pump assembly that provides power to the pump and readings from the left-side tank level sensor.
The pump assembly is mounted to the tank and held in place via a clamp ring that is removed with a "special service tool". This ring clamps the pump's upper section to the opening on the tank and against a stacked set of "O" rings.
The pump is controlled by a "two-step" electrical regulation scheme under PCM control. Two relays in the main fuse box under the hood provide current to the pump in two stages - the initial low-load/start-up/idle output is on the "CIRCUIT" relay and the high-load output is on the "FUEL" relay.
Current from the "CIRCUIT" relay passes through a .34 OHM power resistor located on the air pump assembly bracket prior to powering the pump. This resistor lowers the pump voltage by about 2 volts from the alternator's ~14v output. Current from the "FUEL" relay goes directly to the pump, bypassing the resistor.
Under command from the PCM, these relays close based on current vehicle operating conditions.
The "CIRCUIT" relay is closed at all times that the engine is running or being cranked. It is open (off) when the key is in the "RUN" position and the motor is not running. It also switches off should the engine stop running for any reason or the roll-over sensor in the fuel tank is tripped.
The "FUEL" relay closes around the same time and conditions under which the secondary fuel injectors are enabled, upping the pump pressure output by about 15%.
This scheme is employed purely to reduce noise from the pump and fuel vapor emissions and is NOT a wear-reducing countermeasure. Most modern performance vehicles with an electric fuel pump employ this scheme.
The pump assembly itself is comprised of 5 main components:
The spring-loaded upper section which has the discharge fitting and external connector, the lower fuel "bowl", which accumulates and retains fuel prior to being picked up by the pump, the pressurized main filter and integral fuel pressure regulator, the regulator discharge and siphon assembly and the pump motor itself.
The pump motor is a ~115 lph (nominal) unit made by Arram. When current is applied, it draws fuel in from its pick-up port on the bottom through a plastic filter "sock" that blocks larger particles of crud from entering the fuel system. The fuel is discharged from the upper port under pressure.
Pressure and flow are, of course, inversely proportional, so the volume of fuel that is moved by the pump is a function of the pressure developed after the pump. This pressure is regulated by the main filter and integral fuel pressure regulator, into which the pumps output is sent.
The main filter and integral fuel pressure regulator has three ports: the inlet, the outlet and the pressure regulator discharge.
Fuel is pumped into the main filter assembly and exits the discharge at a rate determined by the integral pressure regulator (about 60 PSI).
When the pressure inside the filter exceeds the regulator setting, fuel is sent back to the fuel bowl via the regulator discharge and siphon assembly.
Fuel passes through a venturi on its way back to the bowl, generating suction on the siphon tube fitting. If excess pressure is generated by the small venturi orifice, it is bled off through a spring-loaded pop-off valve on the top of the assembly.
This is, in a properly operating pump assembly, a continuous operation - fuel is always flowing out of the main filter and through the siphon assembly as the pump should be producing more than 60 PSI at the required flow at all times.
There are essentially 3 failure modes observed with this pump assembly:
1)Loss of flow during normal operation after extended highway cruising
2)Loss of flow during relatively high-G left-hand turns
3)Loss of flow during normal operation after 60k miles or more
Additionally, a drop in pressure may be noted during high demand and will adversely affect engine output and AFRs. Those tuning their PCM may note fairly extreme deviations from commanded fuel values at higher loads.
Though much has been discussed on this forum with regards to the causes of these failures - filter clogging, misalignment of the assembly in the tank, crimped or disconnected siphon hoses, clogging from the use of pre-mix, etc. - all can actually be attributed to partial failure of the pump motor itself.
In every pump I have tested - some that were removed because of these failures, some as regular maintenance and some that were still in service - the pump motor could not keep up with demand under all circumstances.
In many, the pump never produced enough pressure to open the regulator at all. This means that no fuel was servicing the siphon, so no fuel was being moved from the right-side tank to the left-side.
Not a single pump had enough "blockage" of either filter element to restrict flow were the pump up to task. In fact, the sealed main filter cannot restrict flow significantly even if it were somehow completely clogged! The assembly is constructed in such a manner that fuel will flow around the element as it becomes a restriction (something that NONE of the pumps tested had done - even units that were replaced for that very reason by the owner of the vehicle).
Solutions suggested to date:
1) Dismantle and clean the filter elements
As noted, the main filter is not serviceable and wouldn't contribute to reduced pump output even if it became completely blocked. The "sock" on the bottom of the pump motor is serviceable, but none of the pumps I inspected were blocked. Some were dirty or contaminated, but offered no noticeable restriction to pump flow.
2) Replace the entire unit with a new OE unit
So far the most practical solution. At ~$135, it is relatively easy and requires very little action on the part of the user. However, it does not address the under-performing pump motor itself and it will eventually fail again.
3) Replace the entire unit with a new 2009+ OE unit
Also a good possibility. The newer pump system uses a superior Denso pump instead of the Arram and inverts the venturi/bypass mechanism function. At ~$250 or so, it is a bit more expensive and requires some wiring and placement of the pump in a manner that differs with its intended application and orientation.
None of these solutions address the fundamental issue that the OE pump is designed to just barely fulfill the fueling requirements for 250 - 300 HP and probably only does so for a short period of time. Additionally, the OE siphon system will only continue to work as long as the pump is surpassing the fuel demands of the motor. As soon as its output is below demand, the siphon will stop working again. If you are racing and in a high-G left hand turn while accelerating in a high-output RX-8, you will almost immediately starve the pump.
The 09+ assembly addresses some of the siphon issues, but is still designed to provide about 115 lph. A 350 HP+ Renesis will need closer to 200 lph.
Fortunately, the solution for ALL fuel pump issues is relatively easy and inexpensive:
Simply modify the siphon assembly for greater flow and install a high-output pump motor.
The OE siphon assembly cannot take the elevated relief pressures as it stands, so the pop-off valve cap on top of the siphon must be melted on with a hot piece of metal or something similar to keep it in place. Reassemble and reinstall.
Removal and installation of the pump unit is well covered elsewhere on this forum.[/QUOTE]
I've gone through a Walbro and now a DW200 and still the same problems.
THE DIFINITIVE FIX FOR FUEL CUT ON HIGH G LEFTS AND ANY RANDOM LOSS OF FUEL PRESSURE IN A LOWER END HP BOOSTED, STREET, LIGHT TRACK DUTY CAR IS TO ONLY USE A BRAND NEW SLIGHTLY MODDED TO FIT SERIES 2 FUEL PUMP ASSEMBLY.
DO NOT PUT HIGH FLOW PUMPS IN A SERIES 1 ASSEMBLY IT DOES NOT WORK. I HAVE DONE IT TWICE NOW AND IT STILL DOESN'T WORK!
SERIES 2 OEM Fuel Pump Assembly part no. N3R1-13-35Z Some Modifications to fit in a Series 1 fuel tank is required.
End of Scottish quotes in 2014.
.................................................. .................................................. .................................................. .................................................. .................................................. .
This thread is intended to answer some questions about the function (or lack thereof) of the OE RX-8 fuel pump assembly as it is employed on the 2008 and earlier models.
There is a lot of speculation out there about pump efficacy, volume and the function of the siphon system for the saddle-style fuel tank as well as some pretty wild conjecture about the filtration parts, pressure regulation and the control electronics.
The fuel pump assembly is located under an access panel beneath the left-side rear passenger seat. The lower seat cushion simply pulls up and the panel beneath is held in place by 4 sheet metal screws. Since the pump is a "dead-end" style, self-regulating assembly, there is only a single discharge outlet and no return inlet. There is a single electrical connector on the pump assembly that provides power to the pump and readings from the left-side tank level sensor.
The pump assembly is mounted to the tank and held in place via a clamp ring that is removed with a "special service tool". This ring clamps the pump's upper section to the opening on the tank and against a stacked set of "O" rings.
The pump is controlled by a "two-step" electrical regulation scheme under PCM control. Two relays in the main fuse box under the hood provide current to the pump in two stages - the initial low-load/start-up/idle output is on the "CIRCUIT" relay and the high-load output is on the "FUEL" relay.
Current from the "CIRCUIT" relay passes through a .34 OHM power resistor located on the air pump assembly bracket prior to powering the pump. This resistor lowers the pump voltage by about 2 volts from the alternator's ~14v output. Current from the "FUEL" relay goes directly to the pump, bypassing the resistor.
Under command from the PCM, these relays close based on current vehicle operating conditions.
The "CIRCUIT" relay is closed at all times that the engine is running or being cranked. It is open (off) when the key is in the "RUN" position and the motor is not running. It also switches off should the engine stop running for any reason or the roll-over sensor in the fuel tank is tripped.
The "FUEL" relay closes around the same time and conditions under which the secondary fuel injectors are enabled, upping the pump pressure output by about 15%.
This scheme is employed purely to reduce noise from the pump and fuel vapor emissions and is NOT a wear-reducing countermeasure. Most modern performance vehicles with an electric fuel pump employ this scheme.
The pump assembly itself is comprised of 5 main components:
The spring-loaded upper section which has the discharge fitting and external connector, the lower fuel "bowl", which accumulates and retains fuel prior to being picked up by the pump, the pressurized main filter and integral fuel pressure regulator, the regulator discharge and siphon assembly and the pump motor itself.
The pump motor is a ~115 lph (nominal) unit made by Arram. When current is applied, it draws fuel in from its pick-up port on the bottom through a plastic filter "sock" that blocks larger particles of crud from entering the fuel system. The fuel is discharged from the upper port under pressure.
Pressure and flow are, of course, inversely proportional, so the volume of fuel that is moved by the pump is a function of the pressure developed after the pump. This pressure is regulated by the main filter and integral fuel pressure regulator, into which the pumps output is sent.
The main filter and integral fuel pressure regulator has three ports: the inlet, the outlet and the pressure regulator discharge.
Fuel is pumped into the main filter assembly and exits the discharge at a rate determined by the integral pressure regulator (about 60 PSI).
When the pressure inside the filter exceeds the regulator setting, fuel is sent back to the fuel bowl via the regulator discharge and siphon assembly.
Fuel passes through a venturi on its way back to the bowl, generating suction on the siphon tube fitting. If excess pressure is generated by the small venturi orifice, it is bled off through a spring-loaded pop-off valve on the top of the assembly.
This is, in a properly operating pump assembly, a continuous operation - fuel is always flowing out of the main filter and through the siphon assembly as the pump should be producing more than 60 PSI at the required flow at all times.
There are essentially 3 failure modes observed with this pump assembly:
1)Loss of flow during normal operation after extended highway cruising
2)Loss of flow during relatively high-G left-hand turns
3)Loss of flow during normal operation after 60k miles or more
Additionally, a drop in pressure may be noted during high demand and will adversely affect engine output and AFRs. Those tuning their PCM may note fairly extreme deviations from commanded fuel values at higher loads.
Though much has been discussed on this forum with regards to the causes of these failures - filter clogging, misalignment of the assembly in the tank, crimped or disconnected siphon hoses, clogging from the use of pre-mix, etc. - all can actually be attributed to partial failure of the pump motor itself.
In every pump I have tested - some that were removed because of these failures, some as regular maintenance and some that were still in service - the pump motor could not keep up with demand under all circumstances.
In many, the pump never produced enough pressure to open the regulator at all. This means that no fuel was servicing the siphon, so no fuel was being moved from the right-side tank to the left-side.
Not a single pump had enough "blockage" of either filter element to restrict flow were the pump up to task. In fact, the sealed main filter cannot restrict flow significantly even if it were somehow completely clogged! The assembly is constructed in such a manner that fuel will flow around the element as it becomes a restriction (something that NONE of the pumps tested had done - even units that were replaced for that very reason by the owner of the vehicle).
Solutions suggested to date:
1) Dismantle and clean the filter elements
As noted, the main filter is not serviceable and wouldn't contribute to reduced pump output even if it became completely blocked. The "sock" on the bottom of the pump motor is serviceable, but none of the pumps I inspected were blocked. Some were dirty or contaminated, but offered no noticeable restriction to pump flow.
2) Replace the entire unit with a new OE unit
So far the most practical solution. At ~$135, it is relatively easy and requires very little action on the part of the user. However, it does not address the under-performing pump motor itself and it will eventually fail again.
3) Replace the entire unit with a new 2009+ OE unit
Also a good possibility. The newer pump system uses a superior Denso pump instead of the Arram and inverts the venturi/bypass mechanism function. At ~$250 or so, it is a bit more expensive and requires some wiring and placement of the pump in a manner that differs with its intended application and orientation.
None of these solutions address the fundamental issue that the OE pump is designed to just barely fulfill the fueling requirements for 250 - 300 HP and probably only does so for a short period of time. Additionally, the OE siphon system will only continue to work as long as the pump is surpassing the fuel demands of the motor. As soon as its output is below demand, the siphon will stop working again. If you are racing and in a high-G left hand turn while accelerating in a high-output RX-8, you will almost immediately starve the pump.
The 09+ assembly addresses some of the siphon issues, but is still designed to provide about 115 lph. A 350 HP+ Renesis will need closer to 200 lph.
Fortunately, the solution for ALL fuel pump issues is relatively easy and inexpensive:
Simply modify the siphon assembly for greater flow and install a high-output pump motor.
The OE siphon assembly cannot take the elevated relief pressures as it stands, so the pop-off valve cap on top of the siphon must be melted on with a hot piece of metal or something similar to keep it in place. Reassemble and reinstall.
Removal and installation of the pump unit is well covered elsewhere on this forum.
Last edited by 2jzallday; 09-01-2019 at 10:41 PM.
Reason: I made this video because I’m going to be using a fuel surge tank and a External fuel pump also a fuel regulator .
I tried third-party solutions like Walbro and none lasted as a fix. Finally a couple of years ago I had a Series 2 fuel pump installed (with the slight modifications shown here in the forum post link below) and the pump has worked flawlessly ever since, including hard turns and long hot extended highway driving (heavy load conditions) , no issues. That is the best solution in my opinion.
i know this was 10 yrs ago, but i'm hoping someone will answer.
just to clarify, at the bottom of the post, you state that the solution to all fuel pump problems is to modify the siphon assembly and replace the motor. then you say that you have to melt the pop off cap into place.......is that the "modification" you were talking about? is that the only mod, or was there more to the story. im asking because im thinking of going that route and i want to make sure that thats the only thing i need to do. thanks ahead of time
You have to change the plug for the fuel level sender I think and **** around with the siphon tube to get it to work. Otherwise it is supposed to work better.
Heavy track use or turbo I wouldn't expect this to work 100%
In my application the only thing that worked with no issues were 2 lift pumps and a surge tank with a pressure pump in it
hope this isnt a stupid question.....i found this while hunting for a series 2 pump. this kind of looks like a "kit" for the DIY instructions from 10 yrs ago. any confirmation on this?
01-29-2016, 08:52 AM
Common RX8 problem solved !,
