Has anyone ditched both fuel tanks for a single fuel cell? I am thinking about doing that and was wondering how to 'trick' to read the fuel level correctly.

Since there are two sensors, one for each tank, and I'd be going to just one, I wonder if I can use a resistor or something to trick the PCM into thinking one tank is always empty. Then it continues to read the actual sender correctly and the PCM calculates the overall fuel level...

Thoughts? I realize if I did this that I would probably wind up getting a 1/2 full to empty reading and nothing past 1/2 full. That's ok with me. Just as long as the empty reading is correct.

Or maybe the ohms for empty-to-full from the sender can be reprogrammed into the PCM?

Thanks,
Jeff

 

Just wondering why you want to go to a single tank?

 

Well, it's not really for a C5. The tank is going to be used in a street rod, but I am running a C5 PCM. I only want to one run tank but need the PCM to read the level correctly.

 

Ouch ... this may not be easy to do. The PCM not only reads the levels and calculates the fuel gauge reading ... it also checks that the two sensors are "behaving" correctly, and if not, throws a DTC.

The PCM expects to see, say when you fill up, both tanks full. As you drive, it expects the RIGHT sensor to show fuel being used, and the LEFT sensor showing that tank as FULL. Once the RIGHT tank is drained, the LEFT tank sensor then should start to drop and continuously move to EMPTY.

I guess you could fool the PCM by wiring a sensor in as the LEFT sensor and setting it permanently to FULL. The "real" sensor would be wired as the RIGHT sensor, and the PCM should be fine. However, this will mean that when you fill the tank it will show FULL, but when the tank is actually EMPTY the fuel gauge will still show a 1/2 tank level.

You could try wiring the real sensor as the LEFT sensor, and wire the RIGHT sensor as always EMPTY, then you'd get the correct behaviour (At FULL tank the gas gauge would read 1/2 tank, and EMPTY means EMPTY) but I think the PCM will eventually assume the RIGHT tank sensor is "stuck" because it expects to see some fuel in the right tank when you have shut down the engine with fuel in the LEFT tank.

Only other choice is to bypass completely the PCM fuel gauge and wire in a seperate gauge with its own direct wiring to the fuel sensor. The PCM will throw codes, but you could ignore them as they won't affect the fuel level readings you are getting from your own gauge.

See DTC P1431, P1432, and P1433 for a more detailed explanation of the "logic" the PCM uses to monitor fuel levels.

Good luck,

 

You dont need to do any of this..

your using a C5 PCM, but you dont have to use a C5 operating system inside of that PCM, just program the PCM to 2002 camaro/firebird operating system, they only use one gas tank, and then youll also get the best fuel/timing tables for your street rod

One more thing, if your not familiar with tuning, there is a VATS system inside that PCM that will have to be disabled before that PCM will run your engine in your hybrid, any tuner with efi live or hptuners can do all of this for you

EFI Live can re-calibrate the empty to full for the guage, so dont worry about that

actually i have one more question that may throw things off, are you trying to use the corvette guages?

 

I would think the opposite correct? That is, the right tank would be wired permanently empty, the left then proceeds from half-full to empty?

Yes, vette gauges, vette wiring. Although a good idea that I had not thought of, I think the wiring harness will dictate that I probably will need to use a vette PCM program.

Jeff