Engine runs horrible after 45 minutes - Team Camaro Tech
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post #1 of 8 (permalink) Old Jul 31st, 10, 12:53 PM Thread Starter
Dave
 
Join Date: Jul 2010
Location: San Diego, CA
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Engine runs horrible after 45 minutes

1969 Camaro 307 with Edelbrock 650 4bbl

So the car runs fantastic when I first fire it up. If I drive it around for about an hour it starts to diesel a little at idle and feels like it's missing half the cylinders when I hit the accelerator. I have to flutter the gas pedal or it feels like it'll get die out. Eventually it gets up to speed and runs smooth, but it sounds like hell getting there. Everything about this feels like a vacuum issue, but I've replaced all of the tubing recently and checked the seals. I'm going to keep going down that route and get a vacuum gauge but I wanted to throw it out to the community and see if anyone had any other suggestions.
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post #2 of 8 (permalink) Old Jul 31st, 10, 01:04 PM
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Brandon
 
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Re: Engine runs horrible after 45 minutes

Sounds like a vacuum leak,, get some starter fluid and spray the manifold and carb base when it's warm and see if it evens out. If the motor is cold and you spray it then it will bog out if it's got a leak.

Brandon J. licence 1NASTY67

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post #3 of 8 (permalink) Old Jul 31st, 10, 03:15 PM Thread Starter
Dave
 
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Re: Engine runs horrible after 45 minutes

Sounds easy enough. I rechecked my hoses and they're all new with tight connections and no cracks so I have a feeling I'm going to end up with new gaskets. I'll let you know how it turns out.
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post #4 of 8 (permalink) Old Jul 31st, 10, 07:33 PM
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Re: Engine runs horrible after 45 minutes

I would be looking at the carb accel pump linkage adjustment and setting of the sec butterflys...check your choke is setup right and not sticking either.

My Spelling is not incorrect...it is creative

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post #5 of 8 (permalink) Old Jul 31st, 10, 10:35 PM
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Steve
 
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Re: Engine runs horrible after 45 minutes

What ignition do you have?
If electronic, would it be possible that the module/pick-up starts to play up when it gets thoroughly hot and creates a miss?
Food for thought.

Nov 68 Van Nuys. 327 floor-shift-auto, Frost Green and not much else when new.

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post #6 of 8 (permalink) Old Jul 31st, 10, 11:42 PM
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Chris
 
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Re: Engine runs horrible after 45 minutes

I went through the same thing and it turned out to be a bad coil. if you have a spare throw it in and see if makes a difference.

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post #7 of 8 (permalink) Old Aug 1st, 10, 01:25 AM Thread Starter
Dave
 
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Re: Engine runs horrible after 45 minutes

Quote:
Originally Posted by Steptoe View Post
I would be looking at the carb accel pump linkage adjustment and setting of the sec butterflys...check your choke is setup right and not sticking either.
Would this cause the engine to run poorly at times other than just after 45 minutes of run time?

Quote:
Originally Posted by BlackoutSteve View Post
What ignition do you have?
If electronic, would it be possible that the module/pick-up starts to play up when it gets thoroughly hot and creates a miss?
Food for thought.
Not electronic ignition.

Quote:
Originally Posted by 67RSSS View Post
I went through the same thing and it turned out to be a bad coil. if you have a spare throw it in and see if makes a difference.
I don't have a spare, but I'm starting to get the impression that it's somewhere in this area. I've had two mechanic friends tell me to check the condenser and I'm starting to second guess the work of the mechanic that threw the last set of points in the car. I will be checking this out tomorrow.
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post #8 of 8 (permalink) Old Aug 1st, 10, 02:26 PM
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Re: Engine runs horrible after 45 minutes

Not elecronic....check the coil....check the bottom of the coil 1st it will have a 6 or 12 or 25 or 36 stamped on the bottom in amonst some other letters
This (well does in NZ/aussie/England) the voltage rating.
I assume up have the orginal resistance (ballast) wire to the coil it should have 6 stamped.
If one uses a coil outside the voltage it is meant to work at, it gets hot and usually starts to miss after about 20 mins for a little while then the engine dies,
When the coil cools down, the engine fires up fine runs fine and then does the same thing.
Itwas so common yrs ago the coast gaurd boats used to carry spare coils...ppl would put a engine in a boat, use the same coil, wire up and no ballast.....swap the coil for a 12v and will run fine for the next....forever.

My Spelling is not incorrect...it is creative

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