cptncreme

Well finally got the fuel smell when full on my '04, decided to pull the back seat and found that the driver's side is good, has a newer manf. date than the car, so was been replaced in '08. Passenger side is the culprit, leaking thru the electrical connector ......like i stated its only when full, so if I don't fill all the way up will I be ok? I found a great price on an airtex pump module with a coupon code for $365 shipped!

http://www.partsgeek.com/gbproducts/...DJkaAtgu8P8HAQ

Hulk

That's not too bad of a price

kponti

So that's the driverside, what's in the passenger side? I'm guessing sending units? Where can one buy a sending unit setup?

cptncreme

No the one I attached the link for is the passenger side(fuel pumps) side. The drivers side sending unit ones I looked for were about $500. Funny how the sending unit is more than the pumps

AgSilver

Airtex simply resells the OEM pump module. Best to check if it is the most current version.

Hulk

Correct about airtex

nhussain81

I had the same issue and I replaced the passenger side unit. I noticed that one of the terminals had a dark burn mark that distorted the connector housing. What causes this?

I have read that excessive resistance would cause this, but what is the fix. I am afraid it is only a matter of time for this to happen again, if caused by excessive resistance.

Hulk

The filters get dirty and clogged which causes resistance

Worth the wait

Which side controls the gas gauge?

shardul

iTrader: (1)

both sides have float sensors

rockthemullet

I actually think mine was related to power. Since our base fuel pressure is 65psi (quite high compared to the standard 43psi) and the system is returnless, there is probably a good load on the system. I also noticed the harness leading to the pump assembly is heavy while the leads into the pump hat and the pigtails out of the pumps are quite light. This means any failure based on amperage is likely to be seen within the hat.





To combat this, I'll be making a fuel hat out of billet on my downtime this offseason and running a 10-12ga. waterproof bulkhead connector as a new interface from the pumps to the stock wiring harness.

marcmaddox

Are both pumps constantly energized?

cptncreme

Ya think I got luck, only got the gas smell within the past week. My harness side connector is still in good shape. I guess they really mean change them at 60k, I'm at 65k now. Got a replacement on the way. Gonna keep the old basket to get a couple walbro's fabbed in there with upgraded wiring.

kponti

I need to find a spot to mount an external fuel filter. I intend to throw out whatever filter comes with a new sending unit when it's time to replace mine

BC928

I have both units new sitting on my dining room table. I want to take some pics so people understand more of what is being spoken of if they have not held these units themselves.

I will also be keeping the old units, as I would like to find a way to modify them or remake them in different materials to accomplish things like:

1) Large output line size
2) Different intank (and external to tank) fuel pump options
3) Better wiring....


The fuel filter inside the sender (which is also the pressure sensor AS well as the actual (what I believe) is the fpr in the bottom of the case) is a wear item that should be more accessible.

As I add power and e85, I will be concerned over these two units.

turbo97se

I used to have resource to make stuff like this .. I had something similar to this made for my IS300.
https://www.swiftracing.com/SRT/item.aspx?id=112

It'd be great to make the hat portion out of billet aluminum or something .. that is the part that cracks and leaks. If pumps wear out/break they can be replaced with like a pair of Walbros.

rockthemullet

Walbros are not designed for returnless (variable voltage) fuel systems. If you intend on running Walbros, I suggest converting the car to return style. There are a few options out there for returnless systems, I am running two Aeromotive 340LPH Stealths and I think Craig is running AEMs.

You won't be able to run E85 on the stock pumps, I strongly suggest retrofitting bigger pumps right off the bat.

That's the plan, and the hat should be relatively easy to reproduce in billet. Again, I would steer clear of Walbros

99lightning

whats the best place to get new pumps I have 62,000 miles should prob change mine

turbo97se

Please build extras if you can .. yeah I had heard that Walbros may not be good for deadhead fuel systems .. aeromotive or something .. my point was that they can be easily replaced. The hats are not so easily replaced

BC928

I feel like there is some misinformation on what dead head or return less fuel systems means.

There is still a fuel pressure regulator, and there is still an outlet for unused fuel. Volume and pressure in the system, it just simply in the tank.

So you could basically see the entire system out of the tank as the fuel rail on a return system car. The FPR is in the tank and the return line is in the tank, and the pressurized side of things is what you see out of the tank and in the engine bay.

rockthemullet

Incorrect. There is a PRV (Pressure relief valve) within the pump assembly to prevent damage in the event of an overpressure, but the output of the pumps themselves are variable based on voltage. Many returnless systems use a driver module to control the minute adjustments but they're not necessarily needed.

I designed the returnless, twin pump fuel system in the 2nd gen CTS-V back in 2007 when I worked at Denso.

BC928

I have read what you are saying. Lets dig deeper for a second. When I wrote this, I was holding the sender. When you designed the system for Denso - are you saying the pumps were run against the pressure side of the system with NO exhaust relief in normal usage? This is not standard for a returnless system.

There is no pressure relief valve on the pump side. So when you say "Pump assembly" are you referring to the dual basket assembly on the passenger side or the multi-usage piece on the drivers side?

The driver side piece has a pressure sensor the top that has the second small plug that you can see with I believe two pins. You also have the 4 pin plug.

At the bottom of the filter area, there is a steel piece that is held into the plastic body with a strong steel clip. This area also has a line for exhausting the fuel (as in a return).

However, whether or not I have identified some of these sectioned properly ( I believe I have) - a "returnless" system does NOT eschew a FPR. It simply relocates it to the tank. This is what I am saying. Even with a variable speed pump, for longevity, they will not run the pump in a true "bottle corked" manner.

This is my understanding, and I am open to correction, but I have done quite a bit of research.

If there is variability in the voltage supplied to the pumps, it is not according to a FP need in realtime closed loop. It is more of a planned change in needs based upon preset areas of the rev range.

Worth the wait

Thanks!
As always...THE source for info!

rockthemullet

I was not speaking specifically about the E55 pump assembly, I was speaking generically about a returnless fuel system. In a returnless system the pumps are run on the pressure side with an exhaust relief only utilized for overpressure. I designed systems for both Ford and GM where this was the only method used across the company, engineering standard.

I can't speak for our assembly, as I don't have one in my hand, but it may be a deadhead system and not a true returnless system. Regardless, voltage is still variable in a deadhead system. In a true returnless system there is no fuel pressure regulator, whether internal or external to the tank, and voltage variability is indeed based on demand. This is why there are fuel rail pressure sensors used in returnless systems in conjunction with driver modules, for real time response.

shardul

iTrader: (1)

welcome