Re: 1996 Collector Edition Corvette
Posted: Thu Aug 05, 2021 10:09 pm
Here is what I would do:
Fix the fuel sending unit
You have two choices. The first is to get another one. I'm thinking this should be under $200
The second is to fix the current one. You will want to determine if the pump works. This might affect your decision. The rust you have does not look worse than what mine had so the sending unit may be salvageable.
If you choose to repair then disassemble the entire unit, dry it out and clean off the rust. Use the water pressure trick to flush out the pressure and return lines on the sending unit. You should be able to disassemble the fuel sending unit and clean the rust out of it. If you break it then you can just get a new fuel sending unit assembly. Once you clean the rust off everything you can reassemble all but the pump and check the sending unit.
After that you can try the fuel pump. Clean all the rust off it and reconnect it to the sending unit. I used zip ties around the outside to hold it in place. You'll want to hear the pump cycle when you turn the key on. If it doesn't cycle you will need a new pump. You can get the pump separate or as part of the sending unit. If it cycles you will want to flush it out too. This one I'd probably use kerosene.
At this point you will want a new fuel sock - these are cheap
Clean out the fuel lines. You will need to flush out the fuel lines. We'll take the system one line at a time
1) remove the fuel filter
2) disconnect the fuel lines from the fuel injector rail
3) disconnect both fuel lines from fuel sending unit (already done it appears)
4) for each line, I would want to get that rusty fuel/water combo out of the lines. What I did was put water into the lines, then blow it out with compressed air. There are three lines (tank to filter, filter to rail, rail to tank). Keep doing this until what comes out the other end is clean. You can use kerosene or whatever else you want, but the water will flush out all the junk and no messy cleanup.
5) after this I would get a new filter and reassemble
Clean out the fuel injector rail
1) The fuel pressure regulator may also be full of rust. I don't know where this is located on the LT4 but you will want to remove it and clean it out. If it's beyond cleaning get a replacement.
2) The same process you used to flush out the fuel lines you will want to use to flush out the fuel injector rails.
There is a distinct possibility that rust bits made it to the injectors. Depending on what comes out of the injector rails can help guide your decision. If there is just rust color liquid and no chunks it might be OK. Worst case it you get the whole system flushed and the injectors are blocked and they need to be cleaned or replaced.
3) put the pressure regulator back in
put the system back to fuel
1) reassemble all the fuel lines, but do not connect the return line to the sending unit, get a piece of hose and direct it to a bucket
2) put a gallon or two of gas in the tank
3) cycle the fuel pump until clean fuel is coming into the bucket
4) reattach the return line
The water for flushing should not do much damage, as it will only be in there a short time, as opposed to the 3-4 years this one sat with moisture in the tank, and the final assemble will flush out the last bits of moisture and any residuals missed during the flushing. The reason I cleaned out all the lines is to minimize stuff in the filter, and stuff headed to the injectors.
My best guess as to why this happens is these cars have a evap canister that allows air to come in but not go out so easily which I believe is the cause of the water getting into the tank. It's worse when they are left low on fuel.
Would be willing to talk about this so let me know if you want to call and talk it out further
Fix the fuel sending unit
You have two choices. The first is to get another one. I'm thinking this should be under $200
The second is to fix the current one. You will want to determine if the pump works. This might affect your decision. The rust you have does not look worse than what mine had so the sending unit may be salvageable.
If you choose to repair then disassemble the entire unit, dry it out and clean off the rust. Use the water pressure trick to flush out the pressure and return lines on the sending unit. You should be able to disassemble the fuel sending unit and clean the rust out of it. If you break it then you can just get a new fuel sending unit assembly. Once you clean the rust off everything you can reassemble all but the pump and check the sending unit.
After that you can try the fuel pump. Clean all the rust off it and reconnect it to the sending unit. I used zip ties around the outside to hold it in place. You'll want to hear the pump cycle when you turn the key on. If it doesn't cycle you will need a new pump. You can get the pump separate or as part of the sending unit. If it cycles you will want to flush it out too. This one I'd probably use kerosene.
At this point you will want a new fuel sock - these are cheap
Clean out the fuel lines. You will need to flush out the fuel lines. We'll take the system one line at a time
1) remove the fuel filter
2) disconnect the fuel lines from the fuel injector rail
3) disconnect both fuel lines from fuel sending unit (already done it appears)
4) for each line, I would want to get that rusty fuel/water combo out of the lines. What I did was put water into the lines, then blow it out with compressed air. There are three lines (tank to filter, filter to rail, rail to tank). Keep doing this until what comes out the other end is clean. You can use kerosene or whatever else you want, but the water will flush out all the junk and no messy cleanup.
5) after this I would get a new filter and reassemble
Clean out the fuel injector rail
1) The fuel pressure regulator may also be full of rust. I don't know where this is located on the LT4 but you will want to remove it and clean it out. If it's beyond cleaning get a replacement.
2) The same process you used to flush out the fuel lines you will want to use to flush out the fuel injector rails.
There is a distinct possibility that rust bits made it to the injectors. Depending on what comes out of the injector rails can help guide your decision. If there is just rust color liquid and no chunks it might be OK. Worst case it you get the whole system flushed and the injectors are blocked and they need to be cleaned or replaced.
3) put the pressure regulator back in
put the system back to fuel
1) reassemble all the fuel lines, but do not connect the return line to the sending unit, get a piece of hose and direct it to a bucket
2) put a gallon or two of gas in the tank
3) cycle the fuel pump until clean fuel is coming into the bucket
4) reattach the return line
The water for flushing should not do much damage, as it will only be in there a short time, as opposed to the 3-4 years this one sat with moisture in the tank, and the final assemble will flush out the last bits of moisture and any residuals missed during the flushing. The reason I cleaned out all the lines is to minimize stuff in the filter, and stuff headed to the injectors.
My best guess as to why this happens is these cars have a evap canister that allows air to come in but not go out so easily which I believe is the cause of the water getting into the tank. It's worse when they are left low on fuel.
Would be willing to talk about this so let me know if you want to call and talk it out further