KevinInSac

I may have a blown HG on my 3.0, again. I'll know after trying to pressurize the cooling system this saturday. By the way the truck was running prior to getting it into the garage, it made me suspect a faulty fuel injector. Is there anyway to test the fuel injector with out running the engine? I'd rather not run the engine until I confirm whether the HG is blown or not.

abecedarian

The only diagnoses you can perform on a fuel injector without removing it are verifying it's getting a triggering pulse and that it's coil resistance is within spec. Otherwise you'd have to remove the injector(s) to flow and spray pattern test them.

If you have an obvious misfire, then you could, as yota4runna said, find which cylinder is the culprit by pulling sparkplug wires: the one which least affects the engine operation is most likely the cylinder with the issue. Then I'd pull all of the plugs and check them for gap clearance, etc.
I'd skip the injector tests for now and do the above, then if nothing is apparently wrong, do a compression test. If the compression test is inconclusive, a leakdown test should be done. Misfiring can be caused by anything from a spark plug wire arcing to ground somewhere, to valves needing adjusted, to compression issues or even a failing injector.

Targetnut

there is a tool that is available from OTC (part#3398) that connects to the injector and pulses it. You can pressurize the fuel system and then pulse the injector and repeat this test on all the injectors. If one does not cause the pressure to drop as much as the others or not at all that is a bad injector

If you have an oscillosope then you can also check the voltage and current waveforms for anamolies while you pulse the injectors..

KevinInSac

Guys, thanks a ton, You've given me a whole lot to work with. First and fore most, I need to pressurize the cooling system, without that, I'm still shooting in the dark. So, until saturday, let the brainstorming continue.