o1Z0sick

Most of us higher HP guys know about the interesting fuel transfer system. Because of the two separate tanks, GM decided to utilize a non mechanical fluid transfer pump in the passenger tank tapping off the main fuel pump.

This venturi pump has been discussed to death but what I am proposing is doing away with the passenger venturi jet siphon pump. Instead I ask the question about a bilge pump. Just a simple low pressure/volume pump inside the passenger tank to transfer fuel to the driver tank where the main injection pump pickup is located. Fuel could be routed entirely inside the tanks that is up over the cross over hose and spill into the driver tank.

To control the bilge pump, key on power would work but would always run the pump while key was on, float switch so pump powers off when pass tank is empty, or a manual switch in the dash.

I do have some questions to help with design decisions. What is the logic of the PCM for the driver/pass tank level sensors? Should driver side always read more fuel especially close to 1/2 tank? Does the pcm read and display on the gauge cluster the level from the driver side sensor, pass side sensor or both and average?

I might be way out in left field on this one but I really have a good feeling that this may work.

o1Z0sick

Well I thought it may work and to have a dedicated external A1000 fuel pump only feeding the rails. I have horizontal pumps so the lack of support for these is why I thought of this.

cormudd

What you are thinking will work, but the electronics involved for the DIC servive fuel system warning, will not allow you to pass Smog... or now Vehecal inspection. Any error and it is a fail... Then you must spend at least $600 to get a referee to pass you..

lionelhutz

The transfer pump has to move fuel quicker than the engine uses it, so I'd expect it's tank is emptied first.

cormudd

Its the screwy way the ECM analizes the output of the fuel leval sending unit. There is a good post from the guy that used a resistor to bypass the sending unit. If you do that you can probably bypass the Venturi. I think I know what your trying to do.???

lionelhutz

I'm not trying to do anything. But, the simple fact is that the venturi must pump the fuel to the drivers tank faster than the engine uses the fuel. This means it will first empty the passenger tank before the drivers tank is emptied. So, if he mimics that operation with a different fuel system then I doubt there will be any issues with the fuel gauge.

Still, the car is modified so turn-off the fuel sensor codes if all else fails and there would be no issue with passing an OBDII port smog test. That'd cause the gauge gauge to quit working too unfortunately.

cormudd

You can turn off the fuel sensor and disable the error codes???????
Nobody told me that. So I cut holes in my car and weeks of head ache when I could have just dissabled the fuel leval code somehow. How can I do this. ???? just in case. Havent been able to smog now since december....

BigGun

What are the codes (pulled using the dic)? Fuel level codes should not set the service light.

cormudd

P2066. I show emptie all the time and constant service fuel system, as well as low fuel and check engine light. If I disconnect battery and luckey enough to show some reading on gas gauge, it wont be long before service light comes on. Because fuel sender passenger side completly none operational... Have to drive 60 miles or something to clear code and it will not make it 5 miles.

BigGun

You must have a C6. This is the C5 tech area. A search of the code in google will give you several hits from the C6 tech area on this site.

dadaroo

lionelhutz is exactly correct. If it were me, I would add a pump externally and use a float to shut the pump off when level drops low. I probably would design a circuit to use the existing level sensor to also feed a pump controller. I should be able to parallel the level sensor input/output to the PCM to feed the new controller.

One could leave the jet pump in or remove it.

cormudd

The thread is titled, C5 C6 venturi bypass...
Paraleling the level sensor will not work if you read up on how the ECM determins when to send an error code.

cormudd

Wait My bad.. What you are saying will work but now it is just as comlicated as the original crap...

dadaroo

I was thinking about using the sensor to feed a PLC board to control power for the motor on or off. Figured that would be better than trying to install a separate level sensor in the tank. PLC boards are very cheap and easy to program for things like this.

lionelhutz

Since you're hell-bent on hijacking the OP's question and making this thread about your problem - find a resistor the same value as the minimum fuel level and connect that in place of the passenger sensor. Your fuel gauge will read 1/2 tank max and not start to drop until the drivers side tank starts to empty. But, it will work.

Offhand, I don't know the value of the sensor. GM used to use 0-90 ohms but that changed with the LS1 cars.

dadaroo

Lionelhutz, I hope you don't think I was trying to hijack the OPs Thread. My input Posts were meant to provide him with a method to connect an electrical pump to the passenger side. My input was intended to have an automated way to shut the new pump off when the passenger tank was nearing empty.

Sorry if my input was seen that I was trying to solve a problem I had. I'm happy with my OEM design. I will not comment further and let the OP PM me if he wants any further thoughts on the subject.

lionelhutz

It wasn't you hijacking the thread. Sorry about that confusion.