Some background:
93 RX7
The engine work was done by a shop DNA Garage in Costa Mesa Ca.- This work was poorly doner and had all kinds of problems -including the the fuel pump work see the pic.
The car died while on the way to a shop to have brake lines replaced.
Traced it down to a fried fuel pump relay.
With no reason obvious reason for a fried relay we took out the fuel pump hangar to replace the fuel pump as well as the relay.
Below are pics of the relay, pump and exposed fuel pump wiring from hangar top pump.





I cannot get past the exposed wires in the fuel tank, the crimps are not even offset.
We are replacing with the same pump because we have been told a different pump may not work well with the tune the car has.

The new same T1 automotive pump has a connector not just bare wires, and we also bought a connect kit.
My question is:What could be the reason DNA garage cut off the connector and used crimps when they did the install- Do the connectors fail?

 

That pump (if the hellcat pump) can pull a lot of amps and melt the stock connector. Thats why they did the bulkhead. It's not uncommon to have bare crimps in the fuel tank as most types of heat shrink can't handle gas and ethanol. But you are correct in thinking the crimps should be offset.

 

The stock connector is known to go bad (it fries). I'm not familiar with your T1 pump (and it's connector) but I assume it was the same reason they bypassed the connector?
While gasoline is not a conductor, the exposed crimps next to each other do not look good.

Edit: didn't notice twinchargedrx7 already replied

 

Thanks for the replies.
So the connector that comes on the pump (believe it is the hellcat pump) cannot handle the amps the pump can pull?

I have read that heat shrink does not like gasoline, and I suppose that is why those crimps are exposed, the heat shrink practically dissolved.

So I was going to wrap submersible fuel like around the postive crimp (unless I used the connector)

Can this fuel pump also fry the relay- the relay is rated @30amps while the pump @20amps, so I wouldnt think so.
Also, the wiring comes straight off the battery which has a inline 20amp fuse, and that fuse was not blown.

We dont really need such powerful pump, cars does 380hp to the wheels.
I think DNA put it in the incase we anted more HP in the future.
Can I swap out with a pump that pulls less amps and would it work with the tune?

 

Yes, a less-thirsty pump won't affect your tuning. The only way it could do so is if it can't maintain sufficient flow at your desired fuel pressure (Generally 42psi plus boost). It looks like that is an Aeromotive 400 pump. The Aeromotive 340s have the same footprint as the stock Denso pumps and should give you more than enough flow for your current power. I was running a Walbro 255 in my 20B
Also, you are correct in being suspicious of this shop's work. I might be a bit picky about electrical work, but any respectable shop wouldn't use an inline fuse holder from Walmart on such a thirsty pump. Anyone that knows a FD knows that power for the fuel pump comes off the Circuit Opening Relay. And it's already a sufficiently-sized circuit. Also, on North American FDs, there's an open ATO Fuse slot in the Main Fuse Box. Early Japanese FDs have the Telephone Adapter powered here, fused for 20 amps and the Telephone Adapter connector is right beside the Antenna. I see no reason why you couldn't replicate such a setup. I wanna say the terminals are from Yazaki, but you'll have to do some digging there. IIRC, the in-box feed jumpers are 8awg.

As for the flange wiring breach, this is just poor workmanship. Probably 89 cents at Home Depot and zero thinking was involved. If the pump's current draw exceeds what the stock connector can handle, the next step is to use bulkhead connectors. It separates in-tank wiring from external wiring, so there's zero chance of breaching the wire insulation. Aaron Cake did this on his Cosmo a few years ago (check youtube). Alternately, you might find some generic stud-style bulkhead connectors on Ebay for fairly cheap too.

 

You just need to have fuel grade heat shrink, most shop probably don't care to research or carry that kind of stuff. The crimp should be offset, I actually tied the ground wire to the fuel return tube so it can't get close to the positive wire. If done right the stock hanger connector is fine, I've been running an Aeromotive 340 that way for 10 years, and all heat shrinks are still intact last time I pull the pump for inspection 2 years ago.

 

I’ve seen the stock connector fail on walbro 255s to hellcat pumps and everything in between. I’ve also seen it work for years, or work for weeks until burning up again.

With the power a lot of these cars are pushing it’s a no brainer to go bulkhead connector with a bigger connector.

 

It’s all about power draw, not the pump itself. So you have to plan out the max boost you are running, then see what’s the potential amp draw by looking at the pump datasheet. The stock bulk head will work fine on any mildy modded twins car, mine is going on 11th year on 14-15psi on the same pump.

 

I just tackled this today






I had previously drilled holes and used shouldered teflon washers, studs and made my own pass through for heavy gauge wire that I sealed with fuel safe sealant. While it wasn’t elegant, it worked. I went back and did a proper solution today: this is an Aeroflow AF49-4049S connector. This connector is rated for up to 30amps per pin. No risk of melting and full elegance.

https://aeroflowperformance.com/af49...head-connector

Matt

 

I wish my setup looked like that.
DNA garage cut the nipple off the line going to the pump, so right now can only use submersable fuel line to connect the pump.
Looks like you did some welding for the connector coming off the hangar, right?
DNA just drilled a new hole and put in a nylon fitting, the wires just come through the fitting.

The voltage supply to the fuel pump is direct from the battery so ~12.5-14 volts.
Can someone answer if the battery is directly connected to the fuel pump, how would can the amount boost the car tuned for affect the current/voltage to pump fuel pressure if at all?
We had Sakebomb garage put in a rebuilt engine plus new turbo, fuel rails, injectors, hal-tech, basically everything
but they didnt touch the DNA work on the fuel pump.

 

Welding is required for that bulkhead connector install. You have to hole saw a hole a little less than 2” in diameter and you can align it over the factor connector. Any person welding the bung for it should be able to weld closed the nylon fitting they used if you choose to go this route.

It’s very common for the fuel pump to be wired for voltage directly from the battery with larger gauge wire. This allows more draw to the pump. If you just had the connection redone at the pump like mine is done, you should not have to retune the car at all. Ensure that the wire you use in the fuel cell is PTFE coated or some sort of fuel submersible safe wire.

Matt

 

That is the Walbro Universal 535lph In-Tank Fuel Pump E85. The most elegant solution I have found to installing the large flow pumps is the Radium fuel hanger. Radium Fuel Hanger Surge Tank 93+ RX-7

 

I've been way down the rabbit hole with fuel pump stuff.
https://www.rx7club.com/3rd-generati...relay-1149692/

 

Radium hanger looks elegant, but does not look like there is a way to add the fuel level mechanism, right?

 

the fuel level float mechanism does mount to the Radium surge tank body. it is the most challenging part of the swap as it needs to be attached while half of the surge tank is in the FD tank. i recommend you drop the tank to get it done.

the engineering on the Radium system is top notch. it is easily possible running at 500+ rwhp to get fuel starvation on close to half a tank of gas. Radium provides a solution.

 

Will be install it in my new 20B FD that I am building to replace the one I lost in the "war" lol

 

That surge tank pump hanger set up is awesome! It’s just a little overkill for someone with a bolt on FD I run the denso Supra pump rewired and the garage alpha “Hyperion” surge tank cover. Keeps the starvation away and plenty of juice for the 315whp mine makes.

If I had an epic 20b build, of course the radium kit would be on my list

 

What's a surge tank do and do I need one?
We have double to single turbo conversion, haltech ECU, big injectors new fuel rail....
380hp to the wheels.

 

It prevents fuel starvation and allows you to cleanly install multiple high flow pumps.