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Does anyone know if I can add Techron to a full tank of fuel or just an almost empty one and add 12 gallons of fuel per bottle instructions?
I don’t drive it much and winter time it just doesn’t move much. It’ll take a long time to work. My gas gauge won’t read anything but empty. That’s why I wanted to add it. Tank now is full. Anyone with knowledgeable input?
No issue adding to a full tank...it will mix. GM's TSB states to add at fill up.
Techron also comes in 32 oz bottle (complete fuel system treatment) if want more concentration, which you probably do for a fuel gauge arm not reading right.
I wouldn't hesitate to use two 12oz bottles initially to hit the sending unit hard. (24 gals treatment in an 18 gallon tank)
will probably take a few treatments to see if it does any good. Don't overuse it as can be bad for engine. Techron recommends every 3000 miles
Because the fuel constantly circulates between the 2 tanks, you don't have to run it very long before it will be completely mixed.
I don’t get that from reading the attached document. According to what’s described, the right tank has to empty before any fuel starts to transfer, and there’s no mention of any constant circulation between the 2 tanks. Seems to me the best practice is to dump in the additive when both tanks are as empty as possible and then fill until the auto shutoff in the nozzle lets you know the system is full. This would get Techron (or whatever additive you poured in) into both tanks. If you fill first and then add the Techron I don’t see how much if any would end up in the right-side tank. The only constant circulation I see happening is excess fuel being returned back to the left tank from the left tank.
That included info was great. Now I can see how both fuel sensors can read zero at the same time. Complicated fuel system and doesn’t look like fun to remove. If I had a Tach 2 I could tell which side actually failed. Too bad a backup sensor wasn’t designed in. I’m hoping for the miracle liquid to help. Just got this car and am finding lots of things to fix. I have some winter work now. Thanks for including the fuel system info. I always wondered how it worked.
Seafoam will probably do the same if you have that in the cabinet already.
Seafoam will not. Seafoam is effectively just ether, it has very little cleaning properties when diluted into gasoline.
Techron and Gumout Regane and Redline's fuel cleaner are PEA based, and will absolutely clean stuff when dusted into gasoline. PEA will not cause harm if used above stated concentration, until you get to like, absurd levels like 1 gallon PEA in the tank. FWIW Redline SI 12 I think it's called has the highest concentration of PEA, but Gumout Regane is usually the best value (unless you can get the 32oz Techron on sale).
They say to add it to an empty tank with the thought that the fuel being added to the tank on top of the cleaner will agitate the mixture enough for it to mix completely. I suspect in a normal gas tank this happens quickly regardless of when you put it in if you slosh your fuel around enough.
If I had a Tach 2 I could tell which side actually failed.
If the ECM set a trouble code, don't need a Tech2 to see what it is. Any basic code reader....or guy at AutoZone... can pull the code that you can research on here or elsewhere.
P2068 seems to be the most common code as it refers to the passenger (secondary) tank sensor. This sensor fails more often because the right tank gas gets used up first before the remaining 9 gallons in the left tank. Any time your fuel level is below half, the right is empty and its sensor is exposed to air and can accumulate (cheap gas) sulphur deposits on the sensor contacts. Top Tier gas and Techron have additives that keep the contacts cleaner.
I have lived with a bad passenger tank sensor for 10 years. To get the dinging and "service fuel system" stuff to go away, I added resistors to emulate the bad sending unit. Is described here in my write-up
Seafoam will not. Seafoam is effectively just ether, it has very little cleaning properties when diluted into gasoline.
Techron and Gumout Regane and Redline's fuel cleaner are PEA based, and will absolutely clean stuff when dusted into gasoline. PEA will not cause harm if used above stated concentration, until you get to like, absurd levels like 1 gallon PEA in the tank. FWIW Redline SI 12 I think it's called has the highest concentration of PEA, but Gumout Regane is usually the best value (unless you can get the 32oz Techron on sale).
They say to add it to an empty tank with the thought that the fuel being added to the tank on top of the cleaner will agitate the mixture enough for it to mix completely. I suspect in a normal gas tank this happens quickly regardless of when you put it in if you slosh your fuel around enough.
The C6 does not have a "normal" gas tank. It's a 2 tank system, and as I pointed out above, and according to the documentation, if you pour in the additive after you've filled the system, there's no sloshing between the tanks, and the system doesn't try to keep both tanks at the same level.
The C6 does not have a "normal" gas tank. It's a 2 tank system, and as I pointed out above, and according to the documentation, if you pour in the additive after you've filled the system, there's no sloshing between the tanks, and the system doesn't try to keep both tanks at the same level.
2. Unless your fuel sending unit is sulfated, a fuel cleaner may not fix it, but it's probably worth a try first to see if it will help. If it doesn't, you'll probably have to pull the tank and replace the sending unit. There is one in each tank. The one in my passenger side failed and when I pulled it out, all the wiper arms in it were trashed, no amount of Techron would have fixed it. The one in the drivers side tank is attached to the fuel pump.
No issue adding to a full tank...it will mix. GM's TSB states to add at fill up.
Techron also comes in 32 oz bottle (complete fuel system treatment) if want more concentration, which you probably do for a fuel gauge arm not reading right.
I wouldn't hesitate to use two 12oz bottles initially to hit the sending unit hard. (24 gals treatment in an 18 gallon tank)
will probably take a few treatments to see if it does any good. Don't overuse it as can be bad for engine. Techron recommends every 3000 miles
1. Incorrect. You MUST add Techron to an empty tank or it will not get over to the secondary tank.
2 & 3. Techron also comes in a 20 oz bottle, which is the closest to the amount needed for an 18.5 gallon tank. Putting in more than this in a single treatment can lead to problems if done repeatedly, which is what needs to be done if the sender is stuck because of sulfur.
4. I used Techron to free the sending unit in my C5. It took 6 treatments. I STRONGLY suggest you do not treat tankfuls of gas back to back to back to avoid damaging the system. Do a tank, skip a tank, and repeat.
One of the problems using Techron in back to back tanks is fuel dilution. The Techron gets washed into the crankcase and thins out the oil. I like to use it just prior to an oil change for this reason.
Putting it in the tank and letting it sit for a long time, might actually be a good way to de-sufate the fuel sender, as it will give the Techron more time to work on the sending unit. But as I showed above, if your sending unit wiper arms are bent up like mine were, Techron isn't going to do any good.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment that the Fuel gauge goes to empty when the fuel level is greater than what is shown on the gauge and DTCs P2066 and P2636 are present. When these codes are present the Fuel Level Low message should be displayed on the DIC. This could be caused if the ECM does not receive the expected voltage signal to indicate that the fuel transfer is properly occurring. If this condition exists for 30 minutes both of these DTCs will be set. The fuel level sensor card may have slight discoloration possibly caused by fuel contamination which can affect the level sensor output. The fuel level sensor diagnostics are sensitive to this issue.
Recommendation/Instructions:
1) Verify that P2066 and P2636 DTC are set.
2) Confirm fuel rail pressure with the fuel pump on is 58-62 psi. If the pressure is not within this range, follow eSI Service Procedures to correct the issue and then proceed to Step 5.
3) Confirm proper jet pump transfer by checking and recording the fuel level sensor voltages using a Tech2. This must be performed with less than 3/4 tank of fuel. If required, remove sufficient fuel from the Schrader valve on the fuel rail. Follow all safety procedures as outlined in SI. Clear the DTCs to get a reading on the fuel gage. If the secondary (passenger side) sender is less than 2.2 volts and the primary (driver side) is more than .86 volts, the secondary (passenger side) level sensor and the module (includes the jet pump) should be replaced. Prior to replacing fuel hardware confirm all wiring connections are fully seated and harnesses are properly routed. After replacing the level sensor and module move to step 5.
4) If the jet transfer pump is operating properly the fuel sender card may be contaminated. This could cause an incorrect voltage signal to be sent to the ECM. Customers should be advised to correct a contamination issue by adding one bottle of GM Fuel System Treatment PLUS (part number 88861011) to the fuel system on their next fuel fill. Note; the fuel level must be below ¼ tank when the fuel treatment is added. The treatment rate is 1 oz. per gallon of fuel (Using one 20 oz bottle to the fuel system is acceptable). To clean a severely contaminated fuel level sensor, it is permissible to treat the fuel system on two consecutive tanks.
Note: Back to back treatment is only permitted once in the life of the vehicle. After the initial treatment, customers should be advised to add one bottle of GM Fuel System Treatment PLUS to the fuel tank at every oil change, however, not more frequently than once every 3000 miles.
Techron concentrate plus
