Hey Guys,


I picked up a bottle of the ford power flush fluid from the dealer and I was trying to do a fuel injector flush on my 98 Nav. The injector machine we have is the Canister style that connects to a compressed air line. I've used this machine and the ford fluid multiple times on other cars without incident and am familiar with how to use the machine (normally. But this is the first time I tried on my truck. I mixed about 1/2 bottle of the ford Power flush into the canister and mixed it ith a bit of gas. I connectted the Compresses air hose to it and set the gauge to about 45 PSI. Then...

- I disconnected the vacuum line on fuel pressure regulator and plug the vacuum line. I leave the end that is on the regulator open.
- I cut off power to the fuel pump to prevent gas from being fed from the tank.
- I removed the little cap from the schrader valve (sp?) and connectted the injector clean machine to it to feed the cleaner into the injectors.
When I started the cleaning it ran for about a 2 minutes, and died. I could hear a gurguling noise and realeased that the chemical had been pushed back into the tank. I disconnectted and blocked off the main feed line from the tank again and it did the same thing. So it looks like it is being pushed backk through the return line.

Shouldn't removing and pluggin the red vacuum line going to the regulator close the return line an prevent the chemical from flowing back? Is my regulator bad?

 

I could be mistaken, but I'm pretty sure you have it backwards. Doesn't a no vacuum condition open the regulator? That way when the engine is turned off, the pressurized fuel can flow back to the tank.

 

The fuel pressure regulator increases fuel pressure under low vacuum driving i.e. heavy throttle application. What prevents fuel from bleeding back into the tank is a one way Check valve built into the fuel pump. What you want to do is disconnect the pressure line from the rail and feed the rail directly,using slightly less regulated air psi in your cleaner than what the fuel pressure is from the factory. This prevents excess fuel/cleaner from being diverted to the tank.