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Motorhead-47, i am hoping you are still around.
I am looking for specific feedback and/or advise related to the P2066 & P2068 codes for the fuel sender circuit. I would like to hook up external jumper the wires to new replacement fuel senders for testing before going thru the extensive process required to replace the fuel senders in the tanks.
To do this, I am in need of a snapshot of the fuel sender schematic to help determine which two of the three wires coming out of the fuel sending unit plug are used for the sending unit side of the circuit. I would be greatly appreciative of any information explaining/showing the color of the two wires used for the sender side of the circuit. I would like to confirm this before is do something wrong and toast a control board....LOL
I have spent an excess of 100 hours trying to get my things out of my car. It’s a 2007. I finally gave up and just put it back together and it’s going to the dealer. So now I have this question. After you shut your car off how long does it take for your fuel pressure to drop to zero psi? Mine drops to zero pretty much immediately after shutting the engine off and then it has to crank a little bit to build fuel pressure to start.
By the way, I have been working on vehicles for 35 years and I have decided that the C6 Corvette fuel system might be the biggest engineering failure in the history of automotive technology.
I completed the replacement of the passenger side sending unit after getting the P2068 code. A couple of tips that I did not see elsewhere that might help:
1. I used a USB endoscope to see what was going on up near the crossover pipe and could not have done the job it without it.
2. I struggled with unlocking the black plastic ring that locks the crossover pipe to the tank. It is a split ring. I got my fingernal in the split and pulled the ring out of the groove it sits in.
3. Some of the vent tube connections were very tight. I squeezed the plastic clips as hard as I could and some would not budge. I used a pick to remove the plastic that you squeeze which made it a bit easier. They were still tight though, even after I removed the clips.
I am an average DIY/home mechanic and I hate paying others if I can do the job myself. This task is most definitely possible if you have patience. It took me forever. I walked away multiple times, and got lots of cuts and scrapes. Knowing what I do now, I would tackle the project again. It is very expensive to hire out and there is nothing impossible about it. It is just hard and time consuming.
I completed the replacement of the passenger side sending unit after getting the P2068 code. A couple of tips that I did not see elsewhere that might help:
1. I used a USB endoscope to see what was going on up near the crossover pipe and could not have done the job it without it.
2. I struggled with unlocking the black plastic ring that locks the crossover pipe to the tank. It is a split ring. I got my fingernal in the split and pulled the ring out of the groove it sits in.
3. Some of the vent tube connections were very tight. I squeezed the plastic clips as hard as I could and some would not budge. I used a pick to remove the plastic that you squeeze which made it a bit easier. They were still tight though, even after I removed the clips.
I am an average DIY/home mechanic and I hate paying others if I can do the job myself. This task is most definitely possible if you have patience. It took me forever. I walked away multiple times, and got lots of cuts and scrapes. Knowing what I do now, I would tackle the project again. It is very expensive to hire out and there is nothing impossible about it. It is just hard and time consuming.
Good info, Thanks!
I'm dreading tackling mine. Good tip on the endoscope.
Alright, ill wake this thread from the dead, but its been a fantastic thread in helping me taking down my fuel tank and to change the fuel pump.
It really tested my patience though. First, because of the transmission brace i have fitted to my C6z06, the crossover tube cannot be moved rearwards as much as you would like. Second, the crossover pipe and pipes in the tank would not separate, but instead the small hooks and tabs on the tank pipe broke, making everything move with the prying of the crossover tube.
Finally i got that situation sorted, only to find the fuel pump module opening in the tank had been disformed, together with the fuel pump module expanding with the age and fuel. Well, no other way then to start filing away on the opening of the tank to make a conical shape and get the module out.
All in all, i spent about 6 hours and lots of bad words. Now i just need to figure out if i need to buy a new tank pipe, or if i can just plug them in manually before sliding in the crossover tube.
This fuel pump change is getting expensive, IF i can find the hose its probably around 70 usd, shipping another 70 usd, and then tax and import of 30% ontop of that...
I posted this thread originally over 12 years ago and people are still finding it useful! WooHoo!
i'm hoping to limp mine along for as long as i can. my issue is that the fuel level sensor (i'm assuming on the passenger side). is getting fussy.
if i top off to full, the gauge will sweep to full then, sweep back to empty. it'll stay there for maybe 5 - 10 minutes. then read full (5-10 minutes), then back to empty.
this usually cycles about 3x, then it'll go full and read normal the rest of the tank. once it starts reading 'normally', it'll then take 3 engine on / off cycles to clear the P20868 code.
my way of 'limping' along is to guess the amount that is just short of a full tank, doing it that way bypasses all of mis-readings and CEL.
when i have a spare $1,200 laying around, i may pony up and have it fixed properly. until then, it works for me.
it was a great article though.
I posted this thread originally over 12 years ago and people are still finding it useful! WooHoo!
Very useful indeed my friend.
Just put a Z06 pump in my 2011 GS. Wasn't bad getting to the crossover pipe as I have a manual trans car. Was easy to unlock the black lock ring and then the metal collar.
Was a fight getting the tube separated from the tank and of course the internal two lines did not want to separate at first. Had to pull the crossover tube out a bit and then use a pry bar to push the internal tubes off. Really need 3 or 4 hands for this idealy.
I did have to replace the two yellow o-rings in the two small pipes as they got cut in the process but that was pretty easy finding replacements.
I didn’t break the plastic clips that hold the internal lines in but you can tell they were weakened. I did secure them in place with small zip ties which is a very useful tip especially if you do indeed break the small retainers. And this was my only option as both the drivers side and passenger side internal tank pipes are out of stock everywhere and on national back order.
Had to basically rip out the old pump as it would just not fit through the hole in the fuel tank. The opening is just slightly smaller than the diameter of the hole. Probably could trim 1 or 2mm around the hole with no detrimental issues for sealing.
Re-install was much easier going back together. But I did lube everything (two small internal pipe o-rings, large main opening o-rings) with Syl-Glide and that made everything slide back into place with very little effort. Then just twisted the metal collar to lock and put the black plastic lock ring back in place.
Going to finish up bolting everything back together this morning.
Got everything back together and car fired right up. Gas gauge reading correctly. Need to fill her up with gas to finish but should be good to go.
Update. Filled up my car with gas from 1/16th of a tank to full. No problems filling and gauge is reading correctly. So looks like I am good to go.
Last edited by Spaceme1117; Apr 17, 2023 at 07:49 AM.
Very useful indeed my friend.
...Had to basically rip out the old pump as it would just not fit through the hole in the fuel tank. The opening is just slightly smaller than the diameter of the hole. Probably could trim 1 or 2mm around the hole with no detrimental issues for sealing.
Just venting here and I knew when I bought a vette some things would suck, but this is just to most assinine design ever. It would've been so incredibly helpful if they made the tank bulkhead diamter - even a 1/2" larger. Anything would've helped. Not only was getting the pump in an out a signifiant PITA, but the using a wire hanger to fetch the hose connections, clasping the one in and getting the return hose to go into the pump housing for cooling - just make the bulkhead a tiny bit larger. I'd rather have replaced the oil pan seal. End rant.
Just venting here and I knew when I bought a vette some things would suck, but this is just to most assinine design ever. It would've been so incredibly helpful if they made the tank bulkhead diamter - even a 1/2" larger. Anything would've helped. Not only was getting the pump in an out a signifiant PITA, but the using a wire hanger to fetch the hose connections, clasping the one in and getting the return hose to go into the pump housing for cooling - just make the bulkhead a tiny bit larger. I'd rather have replaced the oil pan seal. End rant.
if you still own the 'vette, it's not yet the end of ranting...
Just venting here and I knew when I bought a vette some things would suck, but this is just to most assinine design ever. It would've been so incredibly helpful if they made the tank bulkhead diamter - even a 1/2" larger. Anything would've helped. Not only was getting the pump in an out a signifiant PITA, but the using a wire hanger to fetch the hose connections, clasping the one in and getting the return hose to go into the pump housing for cooling - just make the bulkhead a tiny bit larger. I'd rather have replaced the oil pan seal. End rant.
Honestly, re-connecting the hose connectors to the pump using a piece of wire while quite awkward, to me was not the worst part. Getting the crossover to separate was just the worst. Everything after that by comparison was not too bad.
If I were to have to replace the pump again, I would definitely use a utility knife and trim off a 1 or 2mm around the tank opening. It is really all that is needed to get the pump out.
While I was doing the job, I was trying to imagine exactly how the factory assembled everything. How did they get the internal tubes connected to the pump, etc.? I have to imagine that there was a bit of cussing on their part as well.
these are the reasons why I was quoted $1,200 to replace my fuel pump. actually, it's not the pump, but the fuel level sensor. if I totally fill it up, the analog gauge will cycle 3 times between full and empty (over about 10-15 miles).
once it does settle on full, it will read correctly the rest of the tank. for the last 6 months or so, I fill up just short of a full tank (guessing the gallonage). so far, It seems to work. if the gauge takes a total dump, than maybe I'll fork over the $$$.
Thanks for posting this. If I understand correctly, the fuel is transferred from the right tank by the pump on the driver side. So what does the right side fuel pump do? I'm in the process of replacing my left side fuel pump because fuel is leaking. I haven't found anything about replacing the right side fuel pump, although I was going to replace it as a precaution. What would you suggest?
There's a syphoning/venturi system that works off the flow of the driver side pump to "suck" fuel over from the right tank to the left tank, then it goes through the pump and up to the engine from there.
This is a great post, did mine this weekend. One thing I learned that might help some others trying to do this replacement - I found that unclipping the cross-over tube from the support does not allow much additional movement, removing the support allows the corrugated stainless tube to move/flex much more, it's kind of a pain to remove completely blind but I was able to get a 10mm flex head ratcheting wrench on the bolt and remove it. This was a game changer for us for re-aligning the tube with the fuel tank.
