How to diagnose faulty fuel injector (cylinder not firing)

Sep 02, 2004 2 Replies

Hey everyone,



I have a 94 Explorer, and one of the cylinders is not firing. Spark is okay (checked at coil, and at plug end of wire).



The plug itself was completely coated in oil and crap....we tried replacing the plug, but that did not change anything.



We did a compression test, 145 lbs.



So, the suspicion is that the injector is not injecting fuel.



Any way to test this without removing the upper intake manifold?



Thanks for your suggestions.



Chris


Injector balance test but some specialized equipment is required.....

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and apressure guage can help to diagnose injector flow problems.

Couldn't you just swap injectors between two cylinders and see if the problem follows the injector? And I still would not rule out the spark plug wire. I don't know what the original poster meant by "checked at coil, and at plug end of wire." What fires in open air, doesn't alway fire in the cylinder, especially if the wire's insulation is leaking to ground.

Ed

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