Hard thud from engine during cold start

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  #1  
Old 09-17-2015, 07:14 AM
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Default Hard thud from engine during cold start

Good morning
weird scenario. Lately my car has been doing this thud/shutter only during cold start just before the car completly turns over on the driver side it feels like. I prime the car once or twice before starting it. I replaced fuel pump, filter, fpr and all the fuel stuff. Any thoughts? Thanks
 
  #2  
Old 09-17-2015, 09:05 AM
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Is it just a single thud like one big thud or a lot of little thuds?
 
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Old 09-17-2015, 10:59 AM
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one solid thud just before it turns over. Feels like something isnt catching. But its only on cold starts the rest of the day its fine
 
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Old 09-17-2015, 01:45 PM
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turning the key sounds like your check valve is going on the pump ,that can go on for long time ,could need a .tune up ,or the starter .?
 

Last edited by 95 camaro 406; 09-17-2015 at 06:39 PM.
  #5  
Old 09-17-2015, 01:58 PM
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Kinda sounds like something might be a bit loose but honestly it's hard to say. See if you can get a video of it maybe and let us have a listen. Does it sound like it's coming from under the hood or under the car?
 
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Old 09-17-2015, 02:32 PM
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Ill try to get footage but its one of those things you have to feel. Its def coming from under the hood on driver side. Seems like a spark is not happening. I had a tune up done with new opti and all that and the pump is new as well. The fuel pressure holds but i do have to prime after it sits overnight. It does it slightly int he afternoon now that i noticed it but its smaller thuds. I guess you can call it a slight rumble. I think i may try to replace my wires or something and see if that helps. I dont want to do the parts tossing, no codes are showing up either
 
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Old 09-17-2015, 06:41 PM
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ya the video will help
 
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Old 09-18-2015, 10:16 AM
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sounds like it could be a misfire
 
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Old 09-23-2015, 05:58 PM
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its kind of on and off. I cant get footage of the shake. Ordered some better wires and im going to toss them on this weekend and hope that solves the problems. Thanks all
 
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Old 09-23-2015, 10:17 PM
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what engine so you have?
 


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