I converted to Tanks Inc tank and fuel pump during conversion to E85 and it has worked flawlessly for past few years. I recently noticed a slow drip from under the car and eventually concluded the fuel was leaking from the power and ground wires for the fuel pump. The fuel doesn't leak on the outside of the wires, it somehow goes inside the outer sheath of the wire and drips out when it reach a heat shrink butt connector. I called Tanks Inc and they said while it is very rare, it can happen. I ordered a new pigtail to connect into the fuel pump and gasket, and reinstalled. Within 5 minutes of the pump running the fuel started leaking again! I called Tanks Inc and they are pretty perplexed at how this could possibly happen. Absolutely stumped on this one. Anyone have a similar experience or have any ideas?

 

Is the fuel pump internal to the tank?

 

Yes.

 

The E is creating the problem. Snow provides some sort of E6000 sealer with their meth kits. I'd get some of that and seal the inside of the wire bulkhead.

 

I'm using a GP-8 pump, which is designed for ethanol. Also, the fuel is not leaking on the outside of the wires so a sealer won't help. The fuel is siphoning (or whatever is happening) on the inside of the wire when the pump is running.

 

E85 fuel can be harsh on seals, but you'd think the parts would be resistant to E85 if that's how they're marketed.

Do the wires going to the pump pass through the fuel sending unit? All of the factory setups I've seen use a wire connector at the top of the FSU. Pics would help.

 

Well, why isn't it fixed?

 

THIS ^^ Better yet why are you going to run E85. It costs more and gets less mileage in the long run and is not as efficient as 10% ethanol gas.

 

Don’t understand this comment. Also, running e85 since I have 11.5:1 compression with iron heads. Gas stations in Colorado Springs only carry 91 octane, so I have to run e85 or modify engine to decrease compression ratio. Either way, e85 is not what is causing my fuel pump leak.

 

If the wires going to the fuel pump pass through the FSU I'd re-engineer it to use a wire connector. That would eliminate any wicking of fuel into the wires (E85 or otherwise).

 

Thanks but wires do not go through FSU.

 

The probability of the copper strands wicking fuel out of the tank is next to zero. There's a leak, it's not vented right, or something else.
I have the Tanks Inc setup with zero problems on pump gas. The only thing that didn't work was that stupid fill through cap. It leaked every time I moved forward. They give you 2 vents, a y fitting, and a rollover valve. Mine is mounted to the trunk floor slope above the differential. I also have a return line from the regulator.

 

I’ve had 3 calls now with Tanks Inc and they are stumped. They haven’t mentioned venting once. Open to suggestions on how to check venting. I did bring that up but technician said venting isn’t a factor as the weight of the fuel in the tank is a more significant variable (issue occurs when tank is full and pump is on). I haven’t looked at how the venting works, would taking the fuel cap off be sufficient to test pump again?

 

So, you didn't install it?
It is starting to sound like an error in procedure.

 

I installed it 4 years ago. Has worked flawlessly until now. I do live on a dirt road so could the rollover vent get plugged and cause an issue?

 

If you can fill the tank easily without the pump clicking off every few moments then your vent is fine.

 

I got money on a leak, probably caused by the E85 eating a sealant

 

Fleming442 where do you suspect there could be a leak? Once the leaks were detected I called Tanks Inc and they sent me a new wire pigtail and gasket, which I installed with Indian Head shellac. New wires started leaking almost immediately when pump was turned on. What other part of the pump could have been degraded (that I didn’t replace) that could leak? Only thing Tanks Inc can think of right now is the wire connection isn’t solid and there is excessive amperage going through wires, causing them to heat up and expand. I measured 11.8 volts on wires but my amps reading isn’t working. Will get a new multimeter today and report back off amperage is where it should be, which is below 18 or so

 

You mentioned already that the fuel pump wires don't pass through the FSU. If there's a wire connector on top of the FSU it's physically impossible for fuel to wick into the 12VDC wire and GROUND wire, pass through the wire connector and weep on the bottom side of the car.

 

Olds64 I think I misunderstood your question. Wires do pass through top of fuel pump. Thought you were referring to the other part in the tank that sends a reading to the fuel gauge.

 

Without being able to see the pump in operation it might be hard to determine but . . . I have heard of in tank pumps developing a leak in the pump itself and spraying fuel towards the top of the assembly. I would imagine that could cause it to leak where the wires go through. Is this the type of pump you have ?
https://www.tanksinc.com/index.cfm/p...prod/prd84.htm

You could take it out of the tank and try it with some diesel fuel or varsol and see what it does.

 

More or less the same pump. I have the GP-8 pictured below.

 

You said it is getting into the wire itself ? The only way I can see that happening is some type of capillary action or pressure from the tank like others have mentioned.

 

Is there a seal in the 2 wire connector at the fuel pump? If so, remove the seal and see if that helps.

 

Tanks Inc is sending a new pigtail harness with special coated wires that cannot wick fuel. Will report back once I receive those and get installed.

 

So....Tanks Inc send a new set of wires to come through top of tank. Some special coating that prevents the possibility of fuel wicking up through the wires. Installed new wires, filled tank to very top and zero leaks. Still don't fully understand how this happens but important thing is leak is fixed. Appreciate the feedback from everyone.