Salpolit Posted June 23, 2023 Share Posted June 23, 2023 Hi everyone, I have a new to me Mack RD with a 350 horse E7 mechanical engine. Don't have much history on this engine as to what was done on it, repairs, etc. We had leaking injector lines for #4 and #6 cylinders as the truck currently has the crappy cheap Mack injector lines and the fittings flattened out causing a leak. I replaced #4 and #6 lines with PAI lines (the double nut style). After doing #4 line, all is good. After I did #6 line, the truck has a haze to it when idling and blows a bit of grayish white smoke. When you crack the #6 injector line, the smoke stops. The weird part is it didn't do this before I replaced the line. Could the line somehow be causing this, or do you think it might be an injector hanging open? Any other potential causes? Checked for blowby, truck has zero. Any ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/ Share on other sites More sharing options...
Joey Mack Posted June 23, 2023 Share Posted June 23, 2023 Maybe the well sealed line is showing you that the injector is weak.... And drippy.. Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533498 Share on other sites More sharing options...
Salpolit Posted June 23, 2023 Author Share Posted June 23, 2023 @Joey Mack Would running the 2 different style injector lines cause some type of timing issue with fuel delivery at all? I'm going to swap around injectors this weekend to see if the issue follows the injector Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533506 Share on other sites More sharing options...
Joey Mack Posted June 23, 2023 Share Posted June 23, 2023 I doubt it.. once the lines are full (primed), the amount of fuel delivered by the pump delivery valve is the same amount that is sprayed. cracking the lines individually is a good way to find the cylinder(s) with the issue(s).. If a nozzle is weak or cracked, what have you, it can deliver extra fuel.. I would definately check that.. too much fuel can ''wash'' the cylinder and cause major issues.. I hope some more of the guys will comment on this besides me.. Too many smart men here to name !!! Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533507 Share on other sites More sharing options...
Popular Post fjh Posted June 24, 2023 Popular Post Share Posted June 24, 2023 20 hours ago, Salpolit said: Hi everyone, I have a new to me Mack RD with a 350 horse E7 mechanical engine. Don't have much history on this engine as to what was done on it, repairs, etc. We had leaking injector lines for #4 and #6 cylinders as the truck currently has the crappy cheap Mack injector lines and the fittings flattened out causing a leak. I replaced #4 and #6 lines with PAI lines (the double nut style). After doing #4 line, all is good. After I did #6 line, the truck has a haze to it when idling and blows a bit of grayish white smoke. When you crack the #6 injector line, the smoke stops. The weird part is it didn't do this before I replaced the line. Could the line somehow be causing this, or do you think it might be an injector hanging open? Any other potential causes? Checked for blowby, truck has zero. Any ideas? I think judging by what you have said here the injector got some shit in it on install rust or or something the injector is fouled! 4 Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533534 Share on other sites More sharing options...
Salpolit Posted June 27, 2023 Author Share Posted June 27, 2023 Update, pulled injector number six found it extremely fouled and covered with carbon. Pulled the other injectors, and found all of them, except for cylinder one were fouled out. Most O-rings were torn, and half the injectors did not have the middle O-ring installed. We have six new injectors on their way in. I hope to have them installed by Thursday. Praying this fixes our issue but I think this is the problem. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533669 Share on other sites More sharing options...
Joey Mack Posted June 27, 2023 Share Posted June 27, 2023 when you say ''middle oring'' what do you mean? there are 2 rubber o-rings, and a soft metal sealing ring for around the tip.. there is no o-ring where the injector barrel is screwed together.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533670 Share on other sites More sharing options...
fjh Posted June 27, 2023 Share Posted June 27, 2023 12 hours ago, Salpolit said: Update, pulled injector number six found it extremely fouled and covered with carbon. Pulled the other injectors, and found all of them, except for cylinder one were fouled out. Most O-rings were torn, and half the injectors did not have the middle O-ring installed. We have six new injectors on their way in. I hope to have them installed by Thursday. Praying this fixes our issue but I think this is the problem. the bottom oring has been deleted its a not necessary oring the only orings needed are the ones that seal the fuel from getting out of the steel line and the top oring to keep the oil in the engine! I have seen the older injectors used that has 3 oring groves on the return they deleted the bottom oring ! as Joey mentioned the groove half way down the injector is an assembly point! Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533686 Share on other sites More sharing options...
Popular Post Salpolit Posted July 2, 2023 Author Popular Post Share Posted July 2, 2023 Update: 6 new injectors and ran the overhead and she’s back in business! 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72975-e7-350-mechanical-6-cylinder-smoking/#findComment-533987 Share on other sites More sharing options...
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