Mean Green Posted March 13, 2023 Share Posted March 13, 2023 I know it’s just a pick up but with all the problems I have had with this engine noise Maby this will help others out . My truck is a 2017 gmc with the 5.3 after I gout it I got a cold exhaust leak would make some noise on start up then go away . Then it developed a hard shift from 1st to 2nd when cold and only one time . Then it developed a knocking sound when cold like it had a diesel and you could hear the injectors rattling this would happen when cold for a few miles then go away but if you let it idle for a few min it would come back and then go away after a few miles . Also the fuel mileage sucked if you sat in traffic the fumes got worse . Finally I bought new manifolds and gaskets I only had 1 broken bolt but the last 2 ports were leaking . Fired it up with the leak fixed and no injector knocking and shift problem is gone the exhaust leak caused it to over fuel go figure hope this helps others Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
tjc transport Posted March 13, 2023 Share Posted March 13, 2023 exhaust leaks do strange things to new engines. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment Share on other sites More sharing options...
Mean Green Posted March 13, 2023 Author Share Posted March 13, 2023 Never did I think it would go that far the fuel rail pressure was constantly 2000 plus psi gm states from 500 to 2300 is good but never stated at what speeds or loads Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
Joey Mack Posted March 14, 2023 Share Posted March 14, 2023 Well it's good you got your pick/up, up and running... You saw my post about Yota.. anyway. It is amazing how much is connected to exhaust flow.. it's rediculus. I hope it gives good service for years to come.. my wife's 5.3 only has 60 PSI fuel pressure.. how is yours so high? Hers is a 2004. 1 Quote Link to comment Share on other sites More sharing options...
67RModel Posted March 14, 2023 Share Posted March 14, 2023 2004 is port fuel injection. 2017 is most likely direct injection. Possibly something to do with that? 1 Quote Link to comment Share on other sites More sharing options...
Mean Green Posted March 14, 2023 Author Share Posted March 14, 2023 67 R model your right there is a mechanical high pressure pump under the intake that runs off the cam you can’t test the pressure with a gauge any more only with a scan tool I was going to replace that thinking something failed and it could no longer control filial pressure properly the ecm sends a signal to the pump to control pressure . I’m just glad it don’t sound like a bucket of bolts any more Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
mowerman Posted March 15, 2023 Share Posted March 15, 2023 That’s really weird I wouldn’t of thought that….. right away something in electrical. Glad you got it figured out…. Bob Quote Link to comment Share on other sites More sharing options...
Mean Green Posted March 16, 2023 Author Share Posted March 16, 2023 Thanks bob im glad it’s fixed too and I’m glad I didn’t go the other routes to repair it everything I found on the net and forums was cam and lifter or fuel pump all of witch were expensive I even sent a video to a Chevy tech and he had no clue what was wrong so if this helps someone I’m happy 1 Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
Joey Mack Posted March 16, 2023 Share Posted March 16, 2023 MeanGreen... You did great... I have been on this site for almost 3 years... and in my local world, i know a lot of guys that say they are mechanics, but they talk about 'Tuners' and sensors, and programming,,, blah, blah, blah,... I have been to a few other forums with question's, hoping that I would get ideas from guys that are like the guys here at BMT.. Sometimes I do.. but for the most part,,, guys are so 'Hellbent' on talking tough,, that they tell people to replace, replace, replace.. because the computer said so.. or a guy on a C.B. Radio said to do this and that... Whatever.... Your info on what fixed it is what guys need.. Thanks again... P.S. I hope I wasn't an A-Hole... Jojo 1 Quote Link to comment Share on other sites More sharing options...
Mean Green Posted March 16, 2023 Author Share Posted March 16, 2023 Thanks jojo that’s why I’m always here I like to see what everybody posts cause Maby I will run into it some day and it will help me fix something and if I can help some people along the way I’m happy . I have worked for the local cat dealer for almost 20 years and my dad had a fleet of 10 ford ltl 9000 I have always liked trucks I see rrom your posts you have quite the background too working on just about anything it’s great with guys like us 1 Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
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