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Dies when put into gear

Discussion in 'Engine & Performance' started by 78SierraGrandeTX, Jan 19, 2021.

  1. 78SierraGrandeTX

    78SierraGrandeTX Member

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    Hello Everyone,

    I recently got my engine running good at idle since I did both head gaskets. But now the issue is it dies when put into gear.

    Originally I thought it was the vacuum line that goes from the back of the intake manifold to the transmission. But that seems to be fine.

    Then I thought maybe it isn’t getting gas...but when I have someone press the gas pedal, gas flows out the of carb just fine.

    Any ideas on what could be causing this? Even if I keep one foot on the brake and one on the gas when shifting in gear, it still dies.


    * I know that more information is likely need but here are the basics - sbc 350 ( I believe to be around a 93/94), edlebrock preformed intake, an edelbrock carb, and a th400 transmission.
     
  2. Blackbeard44

    Blackbeard44 Full Access Member

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    what RPM is the truck idleing at?
    what is your initial timings set at?
     
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  3. Bextreme04

    Bextreme04 Full Access Member

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    you need to set idle mixture and idle rpm. Get it fully warmed, set parking brake and block wheels. Put it into drive and set the idle mixture by backing out the mixture screws a half turn at a time(counter-clockwise) until the RPM's peak and start dropping again (You will want to keep the rpm around 750 rpm while you do this). Once it has peaked and started dropping again, screw the mixture screws back in until it peaks again. Once at peak, make sure it is at 750rpm. Then screw the idle mixture in until the RPM has dropped to 600-700rpm. That will make sure your idle mixture is just lean of stoic. The lower the RPM you adjust it too, the leaner the mixture setting will be. Once you have it set, adjust the idle to be where you want it to idle in gear. You probably want about 750rpm in gear. Then go put the truck in park and see what your unloaded idle is. It should be about 800-850 unloaded. If the spread is more than that, you could have a transmission problem or the engine might have a big vacuum leak or a misfire.
     
  4. Bextreme04

    Bextreme04 Full Access Member

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    Oh, and like blackbeard said, before you set the mixture make sure you have initial timing set and that you are setting the mixture with the vacuum advance disconnected and plugged. I would do it all at the same time. You will also want to do the final idle setting at the very end once you have reconnected the vacuum advance.
     
  5. 78SierraGrandeTX

    78SierraGrandeTX Member

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    The tach on it isn’t working as of now, but I have also adjusted the RPM higher and was still getting the same results.

    For the timing, I am not sure on the degrees of it. I will run to the auto parts store and get one. Could it be the timing? I just set it by going to TDC.
     
  6. Curt

    Curt Supporting Member Supporting Member

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    Definitely.You need a timing light,preferably one that has a built in tach.Make sure you firing order is correct
     
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  7. 78SierraGrandeTX

    78SierraGrandeTX Member

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    I can’t put it into drive to mess with the mixtures screws, because once I go to shift it it dies, even if I give it gas.

    I have let the engine warm up too before trying to go into gear
     
  8. 78SierraGrandeTX

    78SierraGrandeTX Member

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    I didn’t even think that this could be a timing issue, I will go ahead and get a timing light then.
     
  9. 78SierraGrandeTX

    78SierraGrandeTX Member

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    I went ahead and adjusted the timing to 12 degrees ATDC ( or very close) , truck starts up great and ideals fine. It tried to run a bit after I put it in gear, but still dies, even if I am giving it gas.

    This weekend, I have someone bringing in another carb that I will try and place on the engine. I know that the carb currenty on the truck has definitely seen it’s better days. I will adjust the mixture screws as y’all had suggested.
     
    Last edited: Jan 21, 2021
  10. 80BrownK10

    80BrownK10 Full Access Member

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    Did this truck ever run right for you? Is this a new issue?
     
  11. OldBlueDually

    OldBlueDually Full Access Member

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    Out of curiosity sake, when the truck is idling will it rev up & down nicely when you ease slowly on the gas and let off? Now how about when you hit the gas harder, what does it do? Hitting the gas harder will put that quick load on the engine without it being in gear, so one would think it may want to sputter/die on you.

    I too believe it is a carb or vacuum issue. I am a firm believer in Rochester Quadrajets, but that is just me. Always had the best luck with them, especially when re-built & tuned right.
     
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  12. Snoots

    Snoots Supporting Member Supporting Member

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    Please tell us you mean 12 degrees BTDC.
     
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  13. Rusty Nail

    Rusty Nail Victim of Culture

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    :popcorn:
     
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  14. 78SierraGrandeTX

    78SierraGrandeTX Member

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    Got the truck running again, and into gear.

    Put on a new edelbrock carb, and the truck now goes into gear!
    The only possible vacuum issues that I can think that it had may have been the vacuum line that runs to the brake booster. However I believe it was the carb, I checked the vacuum line multiple times when I was original having the issue. The only reason I bring this up is being all excited with the new carb I tried starting it without that line connected. Resulting in the truck dieing once shifted into gear. But hey it works now. Took it for a drive and all (after adjusting the idle mixture screws).


    As for the questions, the truck did not have any issues when I would go hard on the gas when it was in park. The engine didn’t have any issues going to high RPM’s then slowly go down.
    And yes the truck did run about 5 months ago, however not well. I replaced the head gaskets along with many other parts since then. Thankful for all the helpful post and comments back to my questions on this forum.
     
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