Rickster42 Posted July 10, 2010 Share Posted July 10, 2010 hey guys, have a bit of a head scratcher on my hands. early build 03 - missing on #5 cyl -25% cont. worse when hot. codes for #5 cont/balance. no other codes. exhaust black. usually starts missing after revved up and the let idle in gear. fuel press = 50psi has had 2 injectors in #5 . injector wire harness is new. relative comp shows ok. comp test reaches 400psi. leakdown test - 5% on that cyl. pushrods look good. anyone? TIA Quote Link to comment Share on other sites More sharing options...
joshbuys Posted July 10, 2010 Share Posted July 10, 2010 I have a set of jumpers so i can "swap injector wiring" made from an old injector harness and two old injector pigtails. They allow me to unplug the injector harness from a suspect injector and one of it's neighbors, hook the jumpers in and route the wiring to the neighboring injector. This is a quick, easy way to diagnose whether it's the injector or the harness. Quote Link to comment Share on other sites More sharing options...
slim Posted July 11, 2010 Share Posted July 11, 2010 First thing that comes to mind is a leaking copper washer letting combustion gas into fuel system, maybe the last injector wasn't torqued, or bolt for hold down streched, or bad cup. Doesn't sound like air in fuel but I can't think of anything else right now. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 11, 2010 Share Posted July 11, 2010 I have seen those oldies with the oil log, get some junk in them and make its way to one injector and prevent oil from properly getting into the injector. Easy enough to rule out just take the rail off and you will know if something is in there causing an issue. Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 11, 2010 Share Posted July 11, 2010 Wouldn't the leaking copper washer beat down the whole bank, eventually, the longer it ran? Quote Link to comment Share on other sites More sharing options...
Rickster42 Posted July 13, 2010 Author Share Posted July 13, 2010 I like that idea of the jumper - but your talking buzz testing with the jumper correct? - all injectors buzz nice on no codes other than low cont #5. or are you using the jumper another way? i`d like to hear more about that. thanks Quote Link to comment Share on other sites More sharing options...
joshbuys Posted July 13, 2010 Share Posted July 13, 2010 Yeah, I use the jumpers when I've got codes, now that I've looked back over this post, I see this wouldn't be very usefuel for you since you have no codes. I've never tried running a truck with the jumpers on, but I can't imagine it would work very well, or tell you anything usefull. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted July 13, 2010 Share Posted July 13, 2010 I've never tried running a truck with the jumpers on, but I can't imagine it would work very well, or tell you anything usefull.To even THINK of attempting this would be akin to attempting to run a gas engine with the spark plug wires arranged in the wrong order wouldn't it? Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 14, 2010 Share Posted July 14, 2010 Everyone's fucked up a firing order at least once... I'm not sure it would be catastrophic, but it probably wouldn't be real good. Quote Link to comment Share on other sites More sharing options...
joshbuys Posted July 15, 2010 Share Posted July 15, 2010 I don't mean it would be catastrophic....I mean there would be no useful diagnostic information obtained from such an endeavor. Quote Link to comment Share on other sites More sharing options...
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