Bad injector?
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Junior User
Joined: Mar 2016
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From: Perrysville ,IN
Bad injector?
I drove this one guy in my truck back to his farm yesterday and he told me it sounded like I had a bad injector and he genarly knows his stuff which leads me to how do I check to see which injector is the bad one. Do I just trail and error or is their a better way? (6.9 no turbo)
More Turbo
Joined: Apr 2015
Posts: 625
Likes: 13
From: W. of Seattle, Kitsap P.
I found this at dieselmann's IDI web pages:
source: Ford diesel 6.9 7.3 IDI
Cylinder missfire
To detect a missfire, you could slowly loosen each injector line to see if the way the engine is running changes, but an easier method is to disconnect the glow plugs and measure their resistance with the engine running (the glow plugs have to be in good condition). As the engine gets hot, glow plug resistance increases. A cylinder that isn't firing will be colder than one that is. After starting, glow plug resistance usually rises to 15-20 ohms on a operating cylinder, but stays below 10 ohms on a weak one--even lower if the cylinder is dead. If you own an infrared temperature gun, you can detect the missfiring cylinder by measuring exhaust port temp. If the miss cannot be isolated to any cylinder(s), then there may be an injection pump or fuel quality problem.
To detect a missfire, you could slowly loosen each injector line to see if the way the engine is running changes, but an easier method is to disconnect the glow plugs and measure their resistance with the engine running (the glow plugs have to be in good condition). As the engine gets hot, glow plug resistance increases. A cylinder that isn't firing will be colder than one that is. After starting, glow plug resistance usually rises to 15-20 ohms on a operating cylinder, but stays below 10 ohms on a weak one--even lower if the cylinder is dead. If you own an infrared temperature gun, you can detect the missfiring cylinder by measuring exhaust port temp. If the miss cannot be isolated to any cylinder(s), then there may be an injection pump or fuel quality problem.
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