Nooch8it

I have a 2011 c6 grand sport a6. I installed long tube headers with 3in xpipe to 2.5in npp exhaust. 450lph fuel pump with hot wire kit and ecs stage 1 feul system that is boost activated. I also have ecs 1500 sc system on the car.
I lost to motor to a fueling issue while tuning and I now have a forged ls3.
My issue now is after replacing the fuel pump I'm still having fuel pressure drop.
The car will have 60psi of fuel pressure on start up but by the time I get to work it's down to 40psi. Then tonight on my 30 min drive home the pressure started out at 60psi dropped during the trip but was back up to 60psi when I got home.
I got a brand new fuel pump and module to install tomorrow but I don't want to drop the tank a third time so any ideas on this would be great. FYI stock pump did the same thing as my current 450lph pump is doing now.

Mike's LS3

Are you going into WOT/boost with a quarter tank of fuel or less? On a Boost a pump set up it can cause the fuel pump to heat up and loose pressure. Fuel helps cool the pump. Just a thought.

I would contact Doug at ECS for advice.

Nooch8it

I spoke with ecs and I'm going to address the points they mentioned. Imy running the new motor na for break-in so no boost. No boost a pump in the car now. The fuel pressure is not wot/throttle dependant it will just fluctuate for no reason. I have run it with a full tank and the results are the same.

extrapilot

Did you replace just the fuel pump or the whole module?

Mike's LS3

Good luck, hope you get this resolved.

Nooch8it

Today I replaced the pump and entire module as a unit with a brand new Z06 unit..... no change. Starts at 60psi and drops to 50psi shortly after. If I trigger the ecs stage 1 system the pressure jumps up. I'm on my 3rd pump replacement now and I can pull the pump tank fast as heck now. This is some bs.

Mike's LS3

Have you checked voltage to the fuel pump while pressure drops?

Nooch8it

I have a hot wire system for both stock and ecs fuel pumps. Both are getting full power from the alternator. I verified that this morning prior to pulling the tank. Looks like I'll be going return style system and removing the stock pressure regulator. I'm running out of options.

extrapilot

Sounds like the fuel is bleeding off somewhere. The right side tank also has a secondary fuel pressure regulator. Not sure how much fuel would be lost if the regulator was faulty, but could be a problem.
Noted as G in right tank. V is the primary regulator, but since you replaced that whole module, that should be good.

Nooch8it

Does anyone know if the fuel pressure regulators in each tank are the same? I have the one in my last sending unit, I don't feel like tossing more money at this only to have it do the same thing. On a good note I can pull a tank on an auto c6 and replace the pump in 4hrs or less.

navy-et

I had this same problem when i did a aeromotive pump swap,
it ended up being the orings on the transfer tubes that connects both tanks together.
I threw all that **** in the trash and made an lines to connect the 2 tanks together. Now i have perfect pressure. hope this helps.

extrapilot

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This is another thought that I was going to bring up, very good advice here..

Nooch8it

OK I was thing this was the issue. How does you fuel level system work with this setup? Does it still read correctly? I think I'm going to go this route. Thats.

Nooch8it

So I pulled both tanks and removed the in tank fuel system to inspect it. I didn't see anything wrong so I set it up outside of the car to see it working. No leaks and the fuel transfer works as it should. I have now replace the entire in tanks system and still have fuel pressure issues. I was able to get low pressure a few times during my testing and noticed the passenger side regulator was oscillating. I replaced it and still noticed the same issue.
So I'm going return style fuel system and not looking back. What are ppls reviews on the lpe c6 regulator block plugs? Does fuel still transfer correctly? Thanks

anthony piper

I just swapped my stock fuel pump with the walbro 450 also and did the Ecs stage 1 e85 fuel upgrade along with it. Just wondered if you kept the set up and if you've had any more problems cause heading what you said has me a little nervous.

Nooch8it

I ended up removing the stock fuel cross over parts and going to a custom return style system. The car made great power on e85 with rock solid fuel pressure. The ecs system is great and worked perfect with the 450 in tank pump. The stick fuel pump wiring didn't last long with the 450 pump so get a hot wire kit and upgraded tank harness....my stock tank harness plug melted.

anthony piper

I have a manual. Is there a way you can attach the links to the parts you are talking about I would appreciate it alot. Thanks again in advance.

Nooch8it

I made the custom fuel system myself so you would need to have knowledge of how to make ptfe fuel line with an fittings. You should be fine with the 450 pump with racetronix hot wire http://www.racetronix.biz/itemdesc.asp?ic=FPWH-008&eq=&Tp=

and the ecs fuel system. Just double check the fuel sending unit for leaks and add clamps to all the hose ends in it.

anthony piper

I looked at the link you sent and order the kit. I was reading right under where I clicked to buy the kit and it said, "When installing a new pump or module we highly recommend purchasing our IPH-008 intermediate pump harness to replace the undersized factory harness. This harness runs between the driver's side wheelwell to the connector on the fuel module at the top of the tank. Access to this area (dropping the tank) is typically required to install this intermediate pump harness."

Do I need to get this also?

Nooch8it

yes it's a good idea to get that as my stock one melted the plug end. After the wire/pump upgrade I had no more issues. Good luck