When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
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.
Any idea what would cause the wiper arms to get bent upward ( or just bent) ? Do these arms normally move somehow/way ?
I'm not 100% sure, but my suspicion is that gas sloshing on curves with a low or half tank may cause the sending unit float to move aggressively enough to damage the wiper arms. I live in a curvy area, so I can see how it would happen. I now try to keep the tank near full as much as I can to reduce the sloshing effect.
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.
All this techron talk lol, is it currently on sale anywhere? I put a 32oz bottle in my take when empty and filled it. Gauge maybe worked three or four times for a few seconds (usually never works).
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.
If you look at the picture at the top of the 3rd page it shows fuel going both ways. I believe the fuel constantly circulates between the two until the right tank is empty.
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.
As more time passes by the factory part will become unavailable. Then one must look into the aftermarket as I was told by a reputable Chevrolet dealership.
I was just reading about Techron® High Mileage Fuel System Cleaner, i wasn't aware of this particular product.
Has this in the description:
-Protect the fuel system and fuel gauge sensor
-Stabilizes fuel for 24 months. Perfect for classic cars and vehicles with infrequent use.
What about just keeping the fuel tanks full rather than below the fuel sensors?
I have already had sensor replaced and both fuel tanks dropped to the tune of $2,300+ a year or so ago but will have to refer to receipt for exact amount as I had auto trans service with fluid and filter changed along with rear end fluid drain and changed with friction modifier. Both services using Amsoil fluids.
If you look at the picture at the top of the 3rd page it shows fuel going both ways. I believe the fuel constantly circulates between the two until the right tank is empty.
You need to read the document carefully. The picture you refer to is figure 4, and what the document states is “When the engine is running (fig. 4), the turbine fuel pump (D) in the left tank pressurizes the fuel feed pipe (M). The entire fuel supply system, from the pump to the injectors, is pressurized. The turbine pump creates more pressure and more fuel flow than the engine needs. Excess pressure and excess fuel is allowed to bleed back into the left tank by the primary fuel pressure regulator (V) within the tank.”
So some fuel is pumped out of the left tank and returns back into the left tank. Fuel does not constantly circulate between the two tanks.
What about just keeping the fuel tanks full rather than below the fuel sensors?
I think this is a more valid approach than relying on miracles in a bottle. Having the right hand sensor bounce around dry seems more likely to cause the wear I see in pictures. Never seen a picture that actually showed the so called "sulfur deposits". All our fuel is ultra low sulfur anyways. Driving around town, I always fill up before I get down to half a tank to keep the right hand sensor submerged. That has to somewhat lubricate and damp motion. But I use Techron 3 times a year and carry a lucky rabbits foot.
If you look at the picture at the top of the 3rd page it shows fuel going both ways. I believe the fuel constantly circulates between the two until the right tank is empty.
You have to understand how the venturi pump in the passenger side tank works. Fuel from the electric fuel pump in the drivers side tank is forced through the venturi pump in the passenger tank. The venturi action then draws in additional fuel from the passenger tank and it gets returned to the drivers tank along with the fuel that was forced through the venturi from electric pump in the drivers side tank.
So more fuel flows back to the drivers side tank through the return line than flowed into the venturi pump from the electric pump. This insures that the passenger side tank is emptied first. Without the venturi pump, there would be no way to get the fuel out of the passenger tank.
The reason they use a venturi pump is because it prevents them from having to install an electric transfer pump in the passenger tank. The venturi action is driven by the flow of fuel from the electric pump in the drivers tank, so a second pump isn't needed.
Last edited by CSixDude; Nov 23, 2024 at 02:21 PM.
fyi: Back in 1982 there used to be only ONE Chevron product in a black bottle with gold lettering. It was used to remove engine deposits, clean injectors etc. It was expensive as I recall and you could only get it from a Chevron gas station. At the time Chevron didn't have these two other separate Techron products (Chevron fuel treatment and Chevron fuel injector cleaner-today).
This engine deposit remover is no longer on the market. I wonder what happened to it? Somehow or someway was it replaced by the latest 2 products from Chevron.
... Fuel from the electric fuel pump in the drivers side tank is forced through the venturi pump in the passenger tank. The venturi action then draws in additional fuel from the passenger tank and it gets returned to the drivers tank along with the fuel that was forced through the venturi from electric pump in the drivers side tank.
So more fuel flows back to the drivers side tank through the return line than flowed into the venturi pump from the electric pump. ...
So the fuel is going to mix between the two tanks and you can dump what ever you want in when ever you want.
The fuel recirculates between tanks. GM probably doesn't want you to add fuel cleaner to a full tank because the concentration in the LH tank would be too high for an unpredictable period of time, and some 'highly concentrated' fuel would certainly reach the engine.
Per the write-up: "Some of the pressurized fuel is directed through a feed pipe (N) inside the crossover hose, to a siphon jet pump in the right tank. The jet pump relies on the venturi effect to use pressurized fuel to draw additional fuel from the tank. The combined fuel then flows from the right tank to the left tank, through a return pipe (P) inside the crossover hose. The jet pump is able to move enough fuel to ensure that all of the fuel in the right tank is consumed before the level in the left tank begins to drop."
A venturi pump is an example of the Bernoulli effect. By pumping fuel with the electric pump (from the LH tank) into a venturi pump in the RH tank, a vacuum is created in the venturi pump that draws fuel from the RH tank. What is returned to the LH tank is a mix of RH tank fuel and LH tank fuel. This process is continuous, so over time, the fuel between tanks is mixed. The rate of fuel being pumped into the LH tank is greater than the consumption of fuel by the engine, which is how the RH tank empties first.
The pump isn’t running when the car is shut off. That’s all you need to know. If your intent is to fill the tanks before you put the car away for the winter and have an equal mix of Techron in both tanks while the car sits, then you need to add it to a nearly empty system and fill up. A short drive home from the gas station isn’t going to mix much between the tanks, and adding the Techron when the tanks are mostly full would result in having most of the Techron in the left tank while the car sits over the winter.
The pump isn’t running when the car is shut off. That’s all you need to know. If your intent is to fill the tanks before you put the car away for the winter and have an equal mix of Techron in both tanks while the car sits, then you need to add it to a nearly empty system and fill up. A short drive home from the gas station isn’t going to mix much between the tanks, and adding the Techron when the tanks are mostly full would result in having most of the Techron in the left tank while the car sits over the winter.
The procedure requires no more than a 1/4 tank of fuel before the additive is poured in. Presumably GM knows how their fuel system operates, so if the fuel mixed so quickly, freely, and easily between the tanks, why would they care how much fuel you started off with?
The procedure requires no more than a 1/4 tank of fuel before the additive is poured in. Presumably GM knows how their fuel system operates, so if the fuel mixed so quickly, freely, and easily between the tanks, why would they care how much fuel you started off with?
Probably because they want a high concentration to clean a contaminated sensor. Not as a prophylactic to prevent contamination.
