Fuel Pump burning out

[quick.msp]

Does anyone have any ideas my mechanic is trying to figure out why my fuel pump keeps burning out on my car, 93 FD with ls3 crate. Fuel pump is a walbro 525LPH, he mentioned something about the pump being wired to the factory mazda pins which seemed very thin.

If anyone has any insight to help out would be greatly appreciated. I finally got the new tail housing on the tremec transmission because it was blowing the rear seal because there was no machining where the seal sits, its a brand new fuel pump and kit, any help would be great.

[AHarada]

The factory fuel pump wiring is definitely not up to the task of supplying the proper current that any aftermarket pumps will require. The factory connector at the fuel pump cover is especially bad, and often creates a short at the wiring inside the connector itself. This happened to my car using a smaller pump than yours, so I repaired it using much beefier electrical bulkheads to pass the wiring through the cover. The pump you are using will draw much more current than stock, so the only way to go about it is to use new wiring of the appropriate gauge (fuel submersible) all the way from the pump to a new relay.

[Bowtie7]

What are you using for a pressure regulator?

[quick.msp]

Thanks for the reply’s, I have the shop running a new wire to fuel pump with new relay.

I do not think there is a aftermarket fuel pressure regulator on the car, will I need one?

I bought the car used it was previously tuned with a walbro 450 pump which died, I assume because of the wiring.

Thanks.

[quick.msp]

Can I wire the fuel pump like this and bypass the bulkhead and Mazda wiring?

[quick.msp]

Any help is appreciated, my mechanic is not that experienced with the RX7:

http://www.radiumauto.com/Fuel-Hanger-Surge-Tank-Mazda-RX7-FD-P1390.aspx

He claims the wiring passing through the fuel hat is an issue, but I also don't want to go overkill on this setup.

The car made 450wheel its a stock ls3 525 with asa cam. I only plan to do some head work and a better cam, what do you guys suggest for setup?

The car had a walbro 525 but it kept shorting out, thanks for any help.

[AHarada]

Rewiring the pump like that takes care of the wiring, but in that video he is still using the factory bulkhead connector. That connector is a huge problem; check out this thread for more details and solutions to it.

https://www.norotors.com/index.php?topic=6346.new#new

[AHarada]

Your mechanic is correct about the bulkhead connector at the fuel hat.

The radium piece is extremely nice and addresses the issue of our cars shifting fuel in the tank and causing fuel starvation. Very expensive as you’ve seen.

Your fuel pump claims to support 900hp, so it may be a tad overkill for your setup. You can use a smaller pump, run good wiring and use a proper wiring pass through at the stock fuel hat and have a solid set up.

[quick.msp]

Thanks that makes sense.

Any idea where I can find this pass through wiring?

He told me to look for a bulkhead connector that's fuel rated, I know nothing about these items.

[jwvand02]

Thanks that makes sense.

Any idea where I can find this pass through wiring?

He told me to look for a bulkhead connector that's fuel rated, I know nothing about these items.

Not sure how much fabrication you/your mechanic are up to, but Ballenger makes a really nice fuel bulkhead connector, this one is weld in and they have a bolt in version that's more expensive:

https://www.bmotorsports.com/shop/product_info.php/cPath/109_631/products_id/5164?osCsid=q8dgu3rd59fk6hqkei4s8l03v3

I ended up making my own fuel hat on my FC. I couldn't use this connector because there just was not enough space but I think the FC fuel hat is quite a bit smaller than the FD.

I actually used these types of pass-throughs:

https://www.mcmaster.com/products/cord-grips/wet-location-multi-cord-grips-7/

They have worked fine and I've had no leaking issues, even though they're not really explicitly for that purpose they are on the top of the tank so they're not remaining submerged. I used teflon coated wire up from the pump, through the cord grip and terminated at a deutsch connector.

This might also be an option:
https://cj-motorsports.com/products/cjm-twin-pump-fd-rx7

If you are paying a mechanic to figure this stuff out for you it might be worth it just to buy that piece or the radium stuff and call it a day, his labor hours will eat up any savings trying to do it economically.

[quick.msp]

Thanks,

I ended up picking up this bulkhead up and will install this with bigger wire + relay. It’s getting wired in tomorrow, will report back how it works.


 https://www.racetronix.biz/p/universal-bulkhead-wiring-system-4-way/bcws-001


The radium part was nice but costly and took a while to get, don’t think I needed that on street car with future plans of just a different cam.

[quick.msp]

update:

everything installed and running perfect, thanks for all the reply's and hoping this can help anyone wiring up a new fuel pump.

[Gunnytron]

Glad you got it sorted. There's some good links to good parts in this thread.

[quick.msp]

Bringing this thread back as my fuel pump wiring issue is fixed with the racetronix bulkhead connector installed by the shop the car was at, but my fuel gauge reading is not working. Now because I never really drove the car before bringing it to this shop for the fuel pump issue , I don’t know if this was a existing issue or if it started after the new bulkhead connector was installed.

I am trying to trouble shoot this and could use some help, I have read threads about corroding ground post and it all seems to be ok (blue and black wire).

 I did notice an existing Mazda connector beside fuel top hat no longer in use, is it possible this has to be connected or grounded?

 The fuel warning light works but the needle is always below E.

Any suggestions?

See photos, thanks

[Exidous]

There are three wires. The ground, fuel warn and fuel level. If level isn't working the wiring is bad or the sender is shot. Based off the modding in the area I'd guess the wiring. The stock bulkhead has two connectors in it. One is pump. One is the warn and level signal