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I filled up my 2008 last night with Costco California 91 "Premium" and the gas gauge went to zero, then came back to full. Over the next 15 miles it went up and down 3 or 4 times. Pulled the code and it's P2068. A quick search on the forum and I see this is a pretty common problem.
I'll be running a couple tanks of Techron concentrate through to hopefully reduce the corrosion from sulfur. Is putting it when the tank is full or empty the way to do it?
Am I doomed to replace the sending unit on the passenger side? Anything else I can do to reverse or slow down the corrosion?
Can’t answer your doomed part, but you want to put the Techron in when the tanks (plural) are near empty. That way you should get a fairly consistent mixture into both tanks.
Techron may or may not help. Do not overuse it....can be harmful. Fats and GM TSB suggest adding to an empty tank. Since the left 8-gallon tank fills first before fuel spills over to the right tank. you might try filling left tank (car half full), add Techron and immediately fill right tank. Might get a higher concentration of cleaner to right tank sensor, I dunno.
If you end up deciding on replacing the right fuel sensor....some things to consider:
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Make sure you get the correct parts. 2005-6 sensors are wrong for a 2008.
Since the job is labor intensive, might do fuel pumps too while in there
The left tank pump is known to crack at the nipple on top. Read up on gas smell and decide if you want to change it too.
The right pump is a non-electric venturi siphon pump so it may be less likely to fail and you may not want to replace. Sensor can come with pump or by itself.
GM had some problems with that unit. I had to replace mine like two months out of warranty. One the more serious issues is that the unit leaks fuel, which is what happened to me. Techron will not hurt your fuel system. The book procedure to replace the unit requires a lot of labor. Someone who knows what they are doing can reduce the labor time.
One known issue with the sending unit is gasoline with too much sulfur content. Shell had this issue and admitted it and replaced damaged sending units.
I took some photos of the wiper arms on the sending unit when I pulled the passenger sending unit in my 2008 after it failed. No amount of Techron would have fixed this. The good news is I was able to drop the passenger tank without removing the transmission or rear end. Just had to pull the X pipe and fender well.
In hindsight, I should have had the dealership replace it when they did the fuel pump leak recall on the drivers tank.
Just got a six pack of Techron. The gauge hasn't acted up again so hopefully a bottle every now and then will keep the code away.
No gas smell. Yet, Just one more thing to worry about.
Is the only time gas goes into the right tank during fill up or does it circulate somehow?
Just got a six pack of Techron. The gauge hasn't acted up again so hopefully a bottle every now and then will keep the code away.
No gas smell. Yet, Just one more thing to worry about.
Is the only time gas goes into the right tank during fill up or does it circulate somehow?
from BWF07 The left hand tank contains the electric fuel pump that supplies fuel to the engine. The right hand tank has a pump, which transfers fuel from the right tank to the left tank. The pump in the right hand tank has no moving parts and is not really a pump. It is a siphon device that uses fuel pressure from the left hand pump to start a siphon that transfers fuel from the right hand tank to the left hand tank. In order to create this siphon, the fuel line that goes to the engine splits and a small amount of pressure is routed to the right hand tank to start the siphoning. The fuel that is being siphoned is routed through another hose to the left hand tank. If the left hand tank is full, the fuel transfers back to the right hand tank through the large filler tube located at the top of the tanks.
The idea is to always keep the left hand tank full whenever there is fuel in the right hand tank.
That right hand pump would be considered a Motive Flow Pump (aviation lingo).
03-21-2024, 09:43 PM
Got the Gas Gauge Code P2068
