fuel injector return flow test questions

hotrdr1983 · Mar 24, 2010

I am doing a return flow test on the injectors of a 2006 with the 5.9 vin c engine. I have the Miller special tools. The test description says to use tool number 9012 at the rear of the fuel filter housing. I am using the line at the top far right side of the truck(looking from under the truck facing foward). Basically, I have two major problems. First, my 9012 fitting is open when you look through it. That mean to me that you are blocking the return flow off from the cylinder head and getting the flow from the filter housing, i.e. you are basically performing a return flow test of the fuel injector pump. Second, i used a Miller 9014 fitting which is blocked off on the ends and has two holes in the sides to allow fuel from the cylinder head to pass through and blocks fuel from the filter housing. Is my logic correct? When i perform the test with the 9014 fitting i get 400 ml per minute. I can block off my injectors and i get a 30 ml drop on # 1 10 ml drop on #'s 4 and 5 and 0 ml drop on 2,3,6. I don't understand my test figures. Even if i substract the 50 ml from the leaking injectors i am still over the 180 ml spec. also what do you guys do with the retrun line to the fuel tank. the test says to route it to a separate container but if i try that, no fuel comes out of my test fitting and hose. Thanks alot for any and all help.

bdsracer · Mar 25, 2010

Where you install the 9012 fitting is where the fuel from the pump joins with the injector fuel return. The fuel from the 9012 fitting is the return from the injection pump. Disconnect the return rubber line from the metal line at the quick disconnect. You will need to run a line from the 9012 fitting into a container and a line from the metal return line that you disconnected below the fuel filter housing into another container to measure for the inj return amount. The test must be done with the 9012 fitting in to separate the pump return from the inj return, so when you do the test, you will have both injector return and pump return flow. The way the 9012 fitting is made, the pump return flows thought the fitting and the injector return flows around the fitting and out the metal return line.

Hope this helps.

hotrdr1983 · Mar 25, 2010

what does your 9012 fitting look like. the one i have has a hole drilled through it. you can see all the way through it. the injector return line from the head is a banjo type fitting. to be able to read the injector return flow you must block the end of the fitting(pump return flow) and let fuel come in from the banjo side of the fitting. solid bolt on end with a crossdrilled passage in it

bdsracer · Mar 25, 2010

Yes the 9012 fitting is a flow through fitting.

No you should NEVER check injector return at this fitting.
Injector return is checked at the metal return line under the fuel filter housing, where the rubber line was disconnected at the quick disconnect, with the 9012 fitting in to isolate inj. return from pump return.

You need to have the 9012 fitting in at the banjo bolt to isolate the injector return from the pump return. If you blocked the pump return, theres no where for the fuel go, it would cause high pressure to build in the pump and cause a false failure.

Run a hose from the 9012 fitting into a container, like a 5 gallon fuel jug, then run the hose from the metal return line at the filter housing into a small container, now the fuel from the 9012 is the pump return, and the fuel from the metal return line is the injector return. The fuel in the small container is the injector return.

hotrdr1983 · Mar 25, 2010

ok. thanks alot. i did the test like you said. i have 100 ml return flow. that test passed. i torqued the hpc's they were all loose. i hope this will fix my intermittent power problem. once again, thanks for the help and information.

fuel injector return flow test questions

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