Knock during start up
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Knock during start up
Hi, I'm new to the forum and hoping for some help. My 2004 powerstroke recently started making a loud knock during the process of starting. Will make the sound warm or cold, however I mostly hear it when the truck is warm as it cranks a little longer and about two seconds into the crank something starts knocking. After the truck starts it runs perfectly fine. And advice would be appreciated.
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Do you think it is internal engine knock, or do you think it is more like a banging noise? Sometimes a broken mount, or even a broken exhaust hangar can make a knocking-banging noise while starting.
If it is internal engine noise, I would say it is most likely a combustion knock. Does it have some exhaust smoke right after start? A combustion knock can be caused by air in the fuel or HPOP, an injector sticking, coolant getting into the cylinder, or even the oil level being too high. You can easily rule out a few things by checking oil and coolant levels first. If it seems like there is a bit more exhaust smoke than normal, I would say it is an injector.
If it is internal engine noise, I would say it is most likely a combustion knock. Does it have some exhaust smoke right after start? A combustion knock can be caused by air in the fuel or HPOP, an injector sticking, coolant getting into the cylinder, or even the oil level being too high. You can easily rule out a few things by checking oil and coolant levels first. If it seems like there is a bit more exhaust smoke than normal, I would say it is an injector.
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Coolant level and oil are fine. And no smoke from the exhaust unless cold (around 30 degrees here) and even that clears up in just a few seconds. I never encountered this problem until switching to the sct street tune from a custom tune. The only way I can describe it is that the truck will crank normally but around 1 or 2 seconds into it will knock very hard twice and then start and rin normally with no problem.
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Oh okay. That might be your answer. I don't know anything about the SCT tune, but tunes change the injector fueling. It might just be normal for the tune. See if somebody who has the SCT tune can let you know what their truck sounds like, or call SCT and ask them.
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