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I don't believe it matters, everything should be the same size but since you are installing the S2 assembly I'd go with the S2 for assurance. Are you talking about the o-ring on pump motor or the o-ring around the pump assembly where it sits on top of the fuel tank?
Hi, I'm talking about the latter.
Thank you in advance
What if i change the whole fuel tank form a series 2 (together with s2 fuel assembly and pump) and remove the s1 fuel tank with everything.
It should be completely plug and play in this case?
Yes you 'should' be OK after a quick check of OEM Part Number changes.
As we know the S2 Fuel Tank is slightly larger in fuel capacity and this was achieved by making the overall tank deeper (larger) by about 11 mm (memory), so the mounting Tank Straps are also different to cater for larger Tank.
All the fuel inputs like Fuel Cover and main supply (hose) appears to be the same/OK.
The Fuel Cut off Solenoids and equipment appears to be slightly different as are the OEM Part Numbers.
So as far as I can see provided you install a 'complete Fuel Tank" you should be OK.
You may see some slight differences with Wiring Loom PLUGS.
You would still need to modify the wire loom for the fuel pump as mentioned in this DIY. Why would you replace all this in the first place though, what is the benefit?
What if i change the whole fuel tank form a series 2 (together with s2 fuel assembly and pump) and remove the s1 fuel tank with everything.
It should be completely plug and play in this case?
Removing the tank is a MAJOR PITA, IIRC... and when I did it, the car was on a lift. Consider what it takes before choosing this route: PPF, exhaust, driveshaft, ...
Just wanted to say thanks for everyone's input and info on this thread. Did the swap recently. Stayed with the S1 tank, and put the S2 sensor unit left side, like in one of the posts here, using a s2 dash board as well with this setup.
Just i would like to add to make things clear for future readers that the cutting and splicing of the wires and connectors is actually for the fuel level sensors, not the fuel pump.
Just accomplished this myself. Was expecting a protracted fight. Took my time and only spent about an hour.
I used a cut off disc on a rotary tool to trim the blank/unpinned part of the connector for the passenger side level sensor. I left enough material behind that it is securely wedged in there.
My fuel pump ring was only mildly annoying using the $20 tool from amazon. The only real issue is that it interferes with the sheet metal after about 10-15 degrees of rotation so I had to move, reset, repeat.
Idle fuel pressure (according to my fabricobbled Arduino gauge) jumped 5 psi and my idle fuel trims dropped from +8% to +1%-ish.
And now, since my old S1 pump still mostly works, I have a spare to give away at track events for limp-home use.
Well I converted a local forum members S1 over to an S2 pump recently and tried to slot and re-use the S1 fuel pump connector for the level float wiring plug as some have done here in the DYI thread. Due to the difference in wire/connector sizes between the two plugs it proved to be too loose of a fit for the thin float wiring and the fuel level gauge started acting up shortly after the job was finished. It was actually fairly easy to pull the wires out of the connector plug without too much force. So I personally don’t recommend doing it that way despite some people getting away with it.
Rather than screw around I just bit the bullet and ordered a new S2 level float to have the proper connector and that solved the problem. A cheaper alternative would have been to cut off the larger wire ends and soldered them on the level float wires, but then you have to deal with that again if you change the float. Maybe could have heat shrinked some sleeves onto the wires to increase their diameter, but then the actual connectors are still small and loose in the plug ends. Couldn’t find a used S2 float assembly anywhere to get the connector plug cheap like when I did mine. So the only good solution was to just pay what it took to do the job right imo; a new S2 float just to rob the connector.
Hi,
Need I to buy the S1 O-ring or the S2 one for the swap?
Thank you in advance
Best regards
I’m not sure if it matters, but the top of the pump mounting surface is essentially the same between the S1 and S2 pump housings. So the safe bet is just get the S1 parts such as tank seal, top nut, O-ring seal, etc. You won’t have any issue doing it that way for sure.
Well I converted a local forum members S1 over to an S2 pump recently and tried to slot and re-use the S1 fuel pump connector for the level float wiring plug as some have done here in the DYI thread. Due to the difference in wire/connector sizes between the two plugs it proved to be too loose of a fit for the thin float wiring and the fuel level gauge started acting up shortly after the job was finished. It was actually fairly easy to pull the wires out of the connector plug without too much force. So I personally don’t recommend doing it that way despite some people getting away with it.
Rather than screw around I just bit the bullet and ordered a new S2 level float to have the proper connector and that solved the problem. A cheaper alternative would have been to cut off the larger wire ends and soldered them on the level float wires, but then you have to deal with that again if you change the float. Maybe could have heat shrinked some sleeves onto the wires to increase their diameter, but then the actual connectors are still small and loose in the plug ends. Couldn’t find a used S2 float assembly anywhere to get the connector plug cheap like when I did mine. So the only good solution was to just pay what it took to do the job right imo; a new S2 float just to rob the connector.
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TeamRX8,
I too have had similar issues with the small wires not fitting in the S2 connector so I went back to modifying the S1 connector to fit. I believe this was linked to a premature failure of my s2 pump, although I have no actual proof.
I understood what you said. Your right my statement uses faulty logic, a level float sensor would have nothing to do with pump operation. It was just my immediate knee jerk idea when the pump went bad.
I did end up buying a S2 Level float connector off a part out to fix the issue, I just have not actually swapped the connectors yet.
While using the correct quick-disconnect connector on the siphon hose might be ideal, IMO just using the proper hose and clamps as indicated below is acceptable and should be issue free if installed properly. All this is doing is siphoning fuel from the RH tank saddle over into the LH tank saddle where the pump is. It has a very low vacuum suction pressure. Some people complained about it thinking it was a high pressure connection. It’s not. While I did buy the proper tool and install the proper quick-disconnect fitting it really was more trouble and cost than it was worth.
Originally Posted by rx8convert22
Next step is to prepare the input hose. As stated the Series I hose is to smaller in diameter to fit onto the Series II pump.
Pictured is the input hose still attached to the Series I pump for reference that you should have removed when you took out your Series I pump. Attachment 182442
Here is a picture of the input hose detached from the Series I fuel pump that is in the fuel tank. You want to cut off the elbow with a utility knife. I've circled roughly how much I cut off. Attachment 182445
This is what it should look like once you've cut it elbow off. Attachment 182446
On the Series II fuel pump you should fit your new hose onto it. Here is a picture of the package of the hose I found through NAPA. It isn't cheep! It was $30 for 1 foot! Don't use any other rating of hose though! This is VERY important since this hose will be submersed in fuel. Attachment 182444
Cut a 5 inch piece of hose and put onto the inlet of the Series II fuel pump and secure it with a worm clamp. Attachment 182443
Ok, well always good to humbled by my own foolishness. Don’t bother putting a new quick disconnect on the pump side siphon imo. Apparently Mazda did it that way just to make it a bit easier to swap the pump module. On the siphon side all they did was use a piece of submergeable fuel hose and some clamps as per the pic below. You might even be able to just order and use that hose and clamps instead. First time I ever pulled the siphon out and never saw any pics previously, though at some point they might have been uploaded somewhere and I missed the thread:
To add insult to injury; it also appears that the S1 RH fuel float has the wiring connector needed to plug the S1 LH fuel float into the S2 fuel pump module. Those should be easy to find in any part out or salvage RX8. Guess that’s what I get for not pulling the entire thing apart. Surprised by how much fuel is in the RH saddle too. Was expecting it to be empty since I ran the pump to empty the tank until it ran dry before installing the S2 pump.
so i was at NJMP Thunderbolt last week. filled the tank to till fuel spill out. go out and do a warm up lap and three hot lap. on the 4th lap, i get fuel starve coming out the octopus turn, 180* tight left turn. i come in and it takes 3 gallons of fuel to fill it up. so i was getting fuel starve with just 3 gallons low from full. i thought it might be a bad fuel pump and got a new DW 300 to replace the pump. but now i'm thinking i'm going to do the S2 pump swap instead. thanks for the write up. FYI, i'm also running e85
I finally got the s2 pump installed. I got Ford fuel line repair kit from autozone, 3/8 fitting 5/16 hose, for the siphon line.
this is how much i cut off the siphon line so the line doesn't crimp up when i added the Ford quick release fitting
the plug in the left is the old s1 fuel level sensor plug. the white plug in the right is the old s1 fuel pump plug. i de-pin the fuel level wires and plug it into the s1 pump plug.
instead of slotting the plug like everyone did, i decided to trim off the plug index tab on the s2 basket with xacto blade. the pins are also offset to the wrong side, so i had to bend them over a little for the plug to seat in all the way.
the angle for the output line was too much and the line got crimp. so i heated up the line and tried to bend it a little and that didn't work, it was too much heat and the line bubble up. so i cut the end off and trim some of the hose of to position it better. but i under estimated how hard it was to reinsert the hose. i tried different ways of heating up the hose to push it on but nothing worked. so i just resorted to rubber hose for now till i can figure something out more permanent
Last edited by trackjunkie; 07-09-2019 at 02:19 PM.
You were supposed to rotate the pump module to align the fitting and barb. The arrow doesn’t have to be pointing forward. That only applies to installing it on the S2 for the tech to install it quickly and have it line up. It will need to be rotated about 60 deg CW to align properly.
if i rotate the pump to align the to output line too much, it will kink the bottom siphon line. the S1 siphon line i oriented at the top so it can swivel if the basket is rotated. also i was concern that the orientation of the pump has to do with the fuel inlet check valve at the basket. i'll have to do a permanent fix for output line now.
Not in my experience on two different RX8s, but I wasn’t there to help you figure it out. Which I’m getting ready to pull mine out and will double check it to be sure. It may just be the way you routed it or something.
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Mine isn’t kinked at all, so maybe you either trimmed too much or too little off
I have spent about 2 years looking for a used S2 fuel level sensor plug to no avail. So, I decided to get creative. It seems that the Mazda3 from the same time has the same plug on its fuel level sensor as the S2 RX-8. This is part number B37F-60-960A. I managed to find a brand new Mazda3 unit on Ebay for $23 shipped. I just received the part, tested it out, and it does indeed fit. I wanted to share this as an alternate source for the electrical connector needed for this swap. It's way better than paying $100+ from the dealer for a new S2 unit. Finding a used Mazda3 unit would probably be even cheaper and far easier than sourcing one from a S2.
it’s good to know, but I’ve seen used S2 fuel level sensors FS numerous times on ebay, one on there right now
I never could find a number to backtrack on finding the connector itself though, that’d be the lowest cost alternative if we could figure that out
I’d think it’d be preferred to de-pin the connectors and use in on the Rx8 float sensor though, it wasn’t clear if you were installing the entire float or not.
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This thread was very helpful for me, so I thought I'd add my 2c to aid others.
If you have an air hammer, us a wide chisel tip to help remove/reinstall the plastic ring. I was able to get the ring off in 5 minutes with this method, didn't break any plastic and didn't have to remove the black plastic tabs! Re-install the same way, but I found it difficult to "thread", so get at least 1-1.5 rotations by hand when reinstalling.
03-12-2018, 04:51 PM
