I would not use any fuel system cleaner. If you insist, be sure to put it in a full
tank. The quote below is from a GM powertrain engineer from a Cadillac site. He is well respected there and I trust his advice.
"All electric fuel pumps for modern fuel injected cars are in the fuel tank and virtually all of them circulate the fuel directly thru the pump to cool the pump. The fuel circulates directly around the armature windings so any harsh solvent in the fuel will eat the varnish like insulation off the armature windings.
This is not a specific problem to Cadillac or GM fuel pumps. Pumps made by Bosch, Nippondenso, Diesel Kiki, Walbro and others are all susceptible to this problem.
Unless your friends that arrived at the conclusion you state have developed fuel systems for automobiles I would say that they are speaking completely from ignorance.
I HAVE developed fuel systems for automobiles and seen MANY failed fuel pumps, from various suppliers, returned from the field. The vast majority of them are failed due to shorted armature windings causing excessive current draw. The shorted armature windings were damaged from chemical/solvent attack from some substance in the fuel. Since those fuel pumps were tested for many thousands of hours in just about any conceivable fuel known to man the conclusion is that some solvent, not normally found in gasoline, was put in the tank.
I have a spool of armature winding wire from a major fuel pump supplier. Solvents in many gas treatments and injector cleaners, if wiped on the wire, will take the insulating coating off. Been there, done that. It happens.
I related an anecdote earlier about my parts cleaning tank that uses a Bosch PFI fuel pump along with dual/dual filters in series with the solvent line both before and after the pump. The tank uses mineral spirits for cleaning solvent. The pump will run forever as long as all it is circulating is mineral spirits. EVERY time someone uses the tank as a catch basin for carb cleaner it kills the pump. EVERY time. Gumout carb cleaner spray is the WORST.....same with Gumout injector cleaner. Need more proof...???
BTW....same is true for injectors....the fuel circulates directly around the windings in the injector...and strong solvents can damage them the same way.
The reason you don't "hear" of this or recognize it is because people do not realize or relate the use of the solvents to the fuel pump failing. They may use the solvent and then have a fuel pump failure months later that was actually instigated by the solvent. They just do not associate the two incidents as it is not part of their thought process that the injector cleaner could be the root cause of the fuel pump failure.
Good luck with the use of the STP product."
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