How do you test glowplugs on 7.3l powerstroke?

Answer 1

You can do a few tests with out removing the valve cover. Remove the 9-pin connectors at both valve covers. The valve cover gasket is also a threw connector for the glow plugs and coils on the injectors. Using DVOM set to ohms black probe to battery ground positive probe to the large pins inside the valve cover gasket both end ones (they are bigger easy to tell) Make sure your only on the one pin it can get tricky just take your time. Now a normal operating circuit for the glow plugs on the 7.3L the ohms reading should be 0.06-0.08 ohms of resistance. If its OL or open then their is an open in the glow plug circuit from the test point to the glow plug under the valve cover. There is another harness under the valve cover that could of come disconnected or burnt. So assuming all connections are OK you can test all 4 glow plugs on that bank doing this procedure. Just do the same to other bank. If the you find OL then either glow plug is bad or harness issue so the V/C will need to be removed for further inspection. You can bench test the glow plug as well and should touch both tips of the GP with the probes (try not to touch plug with hands while doing so) and your readings should be about 0.08ohms. Hope this helps. Good luck.