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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: PStansb on January 20, 2006, 11:34:00 pm

Title: Gasoline motor sounds like diesel?
Post by: PStansb on January 20, 2006, 11:34:00 pm

OK - I'm not sure the best way to describe this, but my 305 V8 gasoline motor often times sounds like a diesel engine when I accelerate.

Any ideas what would cause this, or even what it may be?  Again, I'm sorry for the not-so-technical description, but that's what it sounds like.

This is an 81' C-10 with 305 V8, 4BBL.

Thanks,
Paul Stansberry

Title: diesel
Post by: ChevyGuy on January 21, 2006, 12:21:00 am

Exhaust leaks?

Title: Re: diesel
Post by: toplessblazer on January 21, 2006, 12:55:00 am

Spark knock. You may need to time your engine and try running higher octane gas

Title: Re: diesel
Post by: PStansb on January 21, 2006, 07:48:00 am

I've owned an 80' before that did the same thing and it WAS as simple as running higher octane.  However, I am already running 91 octane in this one and it hasn't resolved the problem.

I'm about to replace the spark plugs and wires...  do you think that would help?

ChevyGuy - When you say exhaust leaks...  what do you mean?  How would that cause the motor to run this way?

Title: Diesel
Post by: Lt.Del on January 22, 2006, 12:11:00 am

Retard your timing a tad.  That is the sound of your valves clattering when you accelerate.

SgtDel

Title: knock
Post by: ChevyGuy on January 22, 2006, 08:16:00 am

The knock is also part of it running bad? I had exhaust leaks before that made it sound that way thats why I said that.

Title: Re: Gasoline motor sounds like diesel?
Post by: 1976Scottsdale on February 18, 2006, 06:21:00 am

This one is a definate long shot, but mine did it twice before I got the message that it was broken.  Make sure that your distributor itself in all the way in.  Mine was hanging out about 3/4 of an inch.  It ran, it just hammered really hard.