robp823 Posted April 12, 2016 Share Posted April 12, 2016 I have a 6NZ in a kenworth that will miss intermittently.Its not logging any faults.Ran injector test and passes.Pulled valve cover and checked overhead, no issues.Had a fuel pressure gauge and road test.Fuel pressure was good.Any thoughts? Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted April 15, 2016 Share Posted April 15, 2016 How many miles on this truck? Air in the fuel and low fuel pressure will cause trouble like this. Spec now is 80 to 90 psi. I have seen before where air has gotten in the fuel from a failing injector seal caused by improperly torqued bolts. I put a sight glass in the return line n snap the throttle or chain it to the dyno to find this.fuel filter bases crack from time to time, n davco filters are always a pain in the ass.How did the harness under the covers look? I have found before where the harness has rubbed on a rocker or the valve cover base n caused n intermittent short. Also oil in the injector pass thru connector can cause grief. Faults don't always log if the fault is only there a short time. How old are the injectors? Quote Link to comment Share on other sites More sharing options...
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