Frequenting no-name, unbranded fuel sold at Flying J and Pilot because their islands were easier to get to was a bad-habit. My ignorance of GM's reliance on the use of fuels with a high detergent content as part of injector health over time is manifesting in my injectors on my 05 Workhorse Chassis. Pilot, which also own's Flying J, does not, has not, and will not sell its customers top-tier fuel and has elected to supply its customers with the low EPA detergent additives which GM states is insufficient to keep its injectors clean. My loyalty to Flying J/Pilot, and my ignorance believing this was all a marketing ploy developed by Chevron and their Techron additive was a mistake.
This started with a rough idle on my 8.1 and a comment from my service writer on injector cleaning on my duramax. Online searched took me to X66P ACDelco upper engine and injector cleaner. My d-max was simple to perform and with my marginal injectors, I saw an immediate improvement in balance rates; all eight are now approaching zero. So I started looking into doing the process on my 8.1. Not so fast. There are a couple of givens; the process must be done in high concentration 16oz cleaner to 64oz of fuel, which requires a separate fuel supply. At idle this takes app 2 hours to run through the motor. The return line goes back to the temp tank and the onboard fuel tank is isolated from the process. This mixture circulates through the temp-tank over and over until depleted. The reason this was simple to perform on the duramax (sierra) is the fuel pump and filter are on the fuel rail, which makes sense because the rail on a duramax is over 20,000 psi, unlike an 8.1 where the fuel rail pressure is app 60psi.
On the 8.1, from burbs to boats to workhorse, it appears there is a single fuel pump in or near the tank and fuel regulator on the fuel rail with a return line to the tank. Now the injector cleaner process becomes more complicated because isolating the fuel tank, also removes the pump and filter. Now to achieve a highly concentrated cleaner a temp pump and filter is required.
To perform this cleaning on the 8.1, the temp-tank setup must also include a pump and filter, differing from the d-max process where the pump and filter were part of the rail. Also the on-board fuel pump would need to have its fuse pulled. This temp pump would need to achieve 56-62 psi or I am assuming the ecm would through a code.
Because of the ease and observable improvement in my injector performance on my d-max, ignorance in running non-top-tier fuel in my 8.1 and a subsequent rough idle, I am investigating how to do this on the 8.1, which is raising more questions.
On the diesel there was little risk, the temp-tank lines were not under high pressure, no external pump or filter were necessary. Now to DIY on the 8.1, if I understand correctly, I need a high-pressure external fuel pump of at least 60psi and an external filter as part of a temp tank assembly. The cost of such a pump is not prohibitive, but the high pressure (100psi) on the supply side to the fuel rail is what is giving me caution, the failure point is a hose clamp to a temp fuel line at a hot motor.
To clean the 8.1, I found a pressure cylinder on Zoro.com. The cylinder is pressurized from external air and has a built in regulator. Depending on the manufacturer, there is a port on the fuel rail where the cylinder charges the rail. On Chrysler and GM this port is type Schrader. To keep the mixture from flowing back to the tank, which can both dilute the mixture and damage the fuel pump, you need to pull the fuse for the fuel pump -and- keep the pressure at least 5 lbs under the pressure of the regulator on the fuel rail. This will keep the regulator closed and prevent backflow to the tank. On the 8.1, fuel rail pressure is 60#. To be on the safe side, I performed the procedure at 50#.
Zoro Canister Fuel Rail Cleaner
The inconvenient truth is this was all avoidable. Now I need to unring the bell and hope it is a recoverable error on my part for not educating myself about injector health, balance rates and the differences in EPA requirements and what Arco, Chevron, Shell and even Valero, are putting into their fuels because of what all vehicle manufacturers want. The damage in frequenting Flying J/Pilot is done and now I need to perform a cleaning process and hope to undo the damage.
Purchasing from Pilot/Flying J over time was a mistake, the remedy was additives at my expense, or a better grade of fuel; but I simply did not appreciate what was happening slowly over time.
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