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Can Someone Help Identify This Knocking Sound?

514 Views 7 Replies 4 Participants Last post by  bryancraftyhands
Good day everyone, I need some help identifying this sound on this 1995 4.3L Astro - It starts on engine on & never fades under any circumstance, and increases along with RPM.


Vehicle is beautful inside & out, then one day it starts stuttering at stops & having a rich fuel smell... I meet a mechanic & mentioned it to him & he immediately said it was the Fuel Pressure Regulator. Sounding right in my head I believe he was competent to do the job.

Day later we open the intake manifold & yes, fuel all over (as YouTube told me would happen if faulty)... .Mechanic replaces it (I bought the part prior), upon reinstalling the piece of the housing that holds the screws opposite the injectors cracks, so we replace the entire 'spider' assembly... A few attempts at installing, leaks appearing & extra O rings being added (not to forget copious amounts of fuel spraying) & it's finally installed and holding properly...

At this time the mechanic tells me that the large amount of fuel that leaked will need to burn out of the system & it will get cloudy, so for this he revs the engine past the point I would ever think necessary... After telling him to not rev the engine so hard & him arguing back about "this is why shops don't let customers into the garage", what he did seemed to clear the system (as massive clouding turned to a small amount). I turn the vehicle off because I feel the vehicle was being overworked, and he wanted it to continue running... During this I'm not particularly recalling hearing any knocking (maybe I was yelling too much), but upon re-start to leave I hear this knocking sound...

Researching on YouTube says it could be a stuck lifter... He tells me new oil will fix that; replaced oil and filter, no change... Is this a natural, motor-made sound or did this guy drop something inside of there? My YouTube research leads me to believe the stuck lifter/rod sound has a different sonic pattern, but maybe somebody knows better than me & I'm just too close to the problem to think clearly... This is my only vehicle & currently cannot afford another one, and this problem seems so minute as everything else is A+ except this problem.

I know every single shop I can bring it to is just going to say "well your engine 'is bad', get another one (& we won't actually have to do any work)" and neither do any actual explanation of the source of the problem nor offer a less $labor-intensive$ answer, & try to charge a $250 look-see fee which they'll never take the job "because of the age on the dash" (vehicle has 130K miles & every record of work ever done since purchase, vehicle was basically perfect before this issue)

I am also in Las Vegas (DI & Eastern) if there is any better mechanics here in the area who can solve this :fingerscrossed:

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Double tap, cracked piston, or wrist pin is now loose. These engines should never be revved over 4k, without a load, and that is when newer. Less with mileage.
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