Question about rebuilt engine

Discussion in 'Chevy C/K Truck Forum' started by okysmokey911, Feb 18, 2010.

  1. okysmokey911

    okysmokey911 Rockstar 100 Posts

    I just rebuilt my 5.7 350 and I have some questions about it. Once i first start her up, the engine idles kind of roughly and the exhaust smells of gasoline. Once the engine warms up, the rough idle goes away, but the gas smell still persists. Any ideas on this? I have already adjusted the idle and messed with the timing some. I'm still thinking its a timing issue.

    93 k1500 5.7 350 tbi

    Forged flat top pistons
    edelbrock 3702 cam
    k&n cold air intake
    Hypertech Chip
    Holley 670 cfm throttle body
    Throttle body spacer
  2. Crakums_GT

    Crakums_GT Epic Member 5+ Years 500 Posts

    IT sounds like it could be a timing issue. Have you tried adjusting the throttle? Maybe it's dumping too much fuel at idle and needs set back a bit. That could be causing a rough idle also because the air/fuel mixture is too rich with fuel.

  3. okysmokey911

    okysmokey911 Rockstar 100 Posts

    Yeah I have tried adjusting the throttle. Its weird because it like starts to cut out once you get into the higher rpms when its a little cold, but like I said once it warms up this is not an issue. I suppose i should try using a timing light to get it just right.
  4. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    it could also be the coolant temp sensor, if they go bad it can cause the computer to dump fuel in at start up to the point of flooding the engine
  5. okysmokey911

    okysmokey911 Rockstar 100 Posts

    Pretty much all of my sensors are new. The temp sensor is the newest one I have replaced.
  6. Gambit

    Gambit Rockstar 100 Posts

    You may want to check the spark plugs. Just becasue they are new doesnt mean they cant fail. if you have the smell of gas in the exhaust it could be becasue it isnt being burned.
  7. okysmokey911

    okysmokey911 Rockstar 100 Posts

    Tested all of the spark plugs and they are good as well as the wires. I guess the only thing it could really be is timing.
  8. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    You say it was a rebuild...

    How many miles were on it?
    Still have the stock Intake Manifold?
    Stock Exhaust Manifold or Headers?
    Still have the CAT's?
    Did you give the throttle body a good cleaning?

    Setting the Timing is a must. Also check the Idle Air Control Valve. Clean it for sure, but for $20 you can replace it.

    I did a rebuild, and I still can smell some gas in the exhaust. But that is cuz' I cut off the CAT's and the Dual Exhaust dumps out just behind the cab.
  9. okysmokey911

    okysmokey911 Rockstar 100 Posts

    How many miles were on it? Well like 135,000 and I blew some piston rings which messed up one of the cylinder walls so I had to rebuild to whole thing. Brand new everything.. The block was bored out, brand new forged flat top pistons, gaskets, rings connecting rods, cam......etc. I put a new intake on it. I still have the exhaust manifolds on it. Never had cats just the dual exhaust. Throttle body is a pretty much brand new holley 670 cfm and I did clean it. I do not know about the Idle Air Control Valve I will check that for sure.
  10. Wpowell

    Wpowell Member

    Are you getting any codes to indicate that it is rich or lean? Usually if your far enough out of tolerance to smell gas its popping a rich code for sure?

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