9V Battery & alligator clips = Open Injector?

ks65stang said:

Please excuse my ignorance; will a 9 volt battery and
alligator clips open/test an injector so I can clean with compressed air? I’m
still learning EFI, bare with me.

http://fordfuelinjection.com/index.php?p=82

Click to expand...

The voltage is Ok, but the little battery may not have enough current to do the job.

Fuel pressure OK, the injectors are not firing, OR one or more injectors stuck open

Do a cylinder balance test: Warm the car's engine up to normal operating
temperature. With the Engine Off, Key OFF, use a jumper wire or paper clip to
put the computer into test mode. Start the engine and let it go through the
normal diagnostic tests, then quickly press the throttle to the floor. The
engine RPM should exceed 2500 RPM's for a brief second. The engine will shut
off power to each injector, one at a time. When it has sequenced through all
8 injectors, it will flash 99 or the number of the failing cylinder such as 22 for
cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause
the test to re-run with smaller qualifying figures. Do it a third time, and if the
same cylinder shows up, the cylinder is weak and isn’t putting out power like
it should. See the Chilton’s Shop manual for the complete test procedure.

The red wire on each injector is powered up whenever the ignition switch is
in the Run position. The computer provides a ground to complete the circuit
and fire the injector. The injector must have a ground to squirt fuel on
command. A short to ground in the injector return wiring can cause one or
more injectors to be continually open or triggered

The wiring for the injectors may have some bare spots in it causing the
injector to computer control wire to ground out. This would cause the
injector to remain on anytime the key was in the Run position. Remove the
injector wiring connectors from the injector. Note that each injector has one
red wire for power and a non red wire (wire some color other than red) for
computer controlled ground. With the key off, disconnect the computer
connector from the computer. Use an Ohmmeter between the non red wire
and ground. You should see more than 100000 (100K) ohms resistance.


See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help




Using the above diagram, check the resistance between the injector and the
computer. Clean and check the 10 pin connectors since they are a potential
trouble source. Any resistance greater than 1 ohm between the injector to
computer wire and the matching pin on the computer connector is a problem.




See http://fordfuelinjection.com/?p=6 for more help

Here's the link to dump the computer codes with only a jumper wire or paper
clip and the check engine light, or test light or voltmeter. You’ll need it to do
the cylinder balance test

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html