I want to test my injectors for flow and spray pattern. I did this on my VW with CIS injection. Ran the pump with a bypass switch, placed injectors in individual bottles, raised intake sensor plate and observed. But I can't come up with an easy way for this truck with the electric injectors on a fuel rail.

Has anyone tested their injectors? And if so, how did you do it? Thanks

92 F-150 5.0L

 

Possibly an OEM style scanner may pulse the injectors during some of it's manual tests. I don't know what the local injection shops use to bench test......must be simular to a scanner.
Phillip

 

One way is to have an injector electrical testor (one that plugs into the injector and sends a selected # of pulses) and a fuel pressure gauge. Turn the key on and let the fuel pump come up to presure, then turn off the switch. Then test each injector and watch how much the fuel preasure drops from injector to injector. You will have to represure the system between injector test. This won't let you see the spray pattern but will let you know how the injectors are flowing compaired to each other.

 

The way I pulse injectors is to use a 555 timer chip driving a mosfet. Here is the basic schematic:



The above schematic will pulse the injector at 144hz, and the adjustment of R1 will control the pulsewidth from 5% duty cycle to 95% duty cycle. 100% duty cycle means the injector never closes, and 0% duty cycle means it never opens, hence the range 5% - 95%. Run the whole circuit on a 12-14V power source and you're good to go. The mosfet in the schematic is suitable for testing one or two injectors at a time. If you need to test all eight injectors at the time you need a larger mosfet. Feel free to substitute as you wish.

M1, the motor in the above schematic, represents the injectors. This circuit can also be used as a PWM motor controller but for your application simply wire in the injectors in place of the motor in the schematic.

For housing and feeding the injectors, I took the two fuel rails off a junked Crown Vic, which has four injector bungs each and the clips to retain the injectors. I simply feed that 45psi of fuel pressure using a fuel pump/level sender/float I took off the same CV, sticking that assembly in a large bucket full of mineral spirits.

Apply power to pump, apply power to circuit, adjust pot and watch the spray patterns. I aim the injectors into an old rubbermaid pan which is about the same size as a kitty litter box to give you an idea of size/shape. You can put baby food jars or something like that under each injector, and pulse for a given amount of time then measure the quantity of mineral spirits in each jar to see if they flow the same, somewhat the same, or not even close. This is how I "match" junkyard injectors actually, using the same test rig.