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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I think my fuel sender unit died whilst wiring up my new gauges and putting 12v through the resistance ground wire.
Unfortunately I'm in Australia, so a replacement is not readily available.
What is readily available is the vy/vz commodore fuel sender units, which use the 240-0 Ohm senders, which would match nicely to the VY commodore gauge cluster I've put in the car.
The problem I have is that the commodore unit has 3 lines coming from the tank, and the firebird has 4 lines.
I was under the assumption you had a breather line, a fuel line and a return line.... what would the 4th be for and is it necessary?
Alternatively, is there a way to repair the the resistor/diode on the old sender unit?
Or just change over the sender section of the assembly?
I've got a new 140GPH pump to put in, but just want to make sure I can do it all at once before ripping the ***-end out of the car to do it.
Also if someone can identify the lines in an image and where they go that would be awesome.
Re: Replacing 3rd gen fuel sender with different type
Stuie your right about the three lines , one is the pressure feed to the fuel rail from the pump , one is the return back to the tank from the regulator , and the third one goes to the charcoal canister to trap gas fumes that would otherwise vent to the atmosphere , and then when the ECM tells it to a canister purge valve opens and the offending fumes are burned in the engine . So that brings us to line #4 . Line #4 goes to that little plastic valve that's supposed to be on a bracket on the car's left hand side (U.S. driver's side) right in the same general area that the fuel filter is found . This valve is a two way valve that will open if too much vacuum is built up in the tank to let air in , and will also open if there is too much pressure in the tank to vent some out . It is my understanding that in normal operation the charcoal can is supposed to the the primary vent and the weird little valve being a safety device whose opening pressure/vacuum is greater than the normal venting that would happen with the can . There are a bunch of threads kicking around here about taking that valve apart and cleaning it , and a few threads that start with "There is this hose hanging down near the fuel filter" in the case where the valve has gone missing .
02-12-2017, 05:17 PM
Stuie your right about the three lines , one is the pressure feed to the fuel rail from the pump , one is the return back to the tank from the regulator , and the third one goes to the charcoal canister to trap gas fumes that would otherwise vent to the atmosphere , and then when the ECM tells it to a canister purge valve opens and the offending fumes are burned in the engine . So that brings us to line #4 . Line #4 goes to that little plastic valve that's supposed to be on a bracket on the car's left hand side (U.S. driver's side) right in the same general area that the fuel filter is found . This valve is a two way valve that will open if too much vacuum is built up in the tank to let air in , and will also open if there is too much pressure in the tank to vent some out . It is my understanding that in normal operation the charcoal can is supposed to the the primary vent and the weird little valve being a safety device whose opening pressure/vacuum is greater than the normal venting that would happen with the can . There are a bunch of threads kicking around here about taking that valve apart and cleaning it , and a few threads that start with "There is this hose hanging down near the fuel filter" in the case where the valve has gone missing . 