Motor sputters out under heavy acceleration at higher RPMs - Team Camaro Tech
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post #1 of 7 (permalink) Old Apr 15th, 02, 05:28 AM Thread Starter
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I have a 1967 Camaro all restored back to stock condition. The motor has 900 mile since a complete rebuild. The carb is the original Q-Jet that is rebuilt. When I drive the car, it starts great, idles great, runs under normal conditions great. But when it is time to have fun and put the acclerator down, the engine will sputter and lose all power, almost like there is a rev limiter or something. Yesterday, at about 3500 rpm in third with the accelerator floored, it lost all power, but the motor did not die, it sounded like it was just idling. It would not respond to the accelerator pedal at all. I turned on a side street and a few seconds of just idling and I was on my way again. Again, this occurs ONLY under full acceleration and ONLY above 3500 RPM or so.
I thought that the car may be running out of gas with the secondaries open, so I installed a larger needle and seat and hi-flow fuel filter but that did not help. Would you guess it is still in the fuel system somewhere? The coil giving out at higher rpm? The coil arcing maybe? The distributor doing something weird (I have not gone through the distributor yet)? Or something else? If there are any steps or tests you recommend, I would really appreciate it. Thanks in advance.
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post #2 of 7 (permalink) Old Apr 15th, 02, 07:18 AM
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hows the fuel pressure?
5 1/2 to 6 psi is normal for stock pump.

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post #3 of 7 (permalink) Old Apr 15th, 02, 09:00 AM Thread Starter
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I have not tested the fuel pressure with a gauge, but can tell you it seems to come out very strong. I will add the fuel pump to the list haha. Thanks.
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post #4 of 7 (permalink) Old Apr 15th, 02, 09:47 AM
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The next time this happens, do this.

When engine acts up, turn off IGN switch and keep pedal to floor. Coast to a safe spot on the side of the road. Raise hood, remove air cleaner, and insert a pipe cleaner into bowl vent and retract cleaner.

Check the end of pipe cleaner for gas moisture. If there is none, fuel delivery problem. If there is fuel, then ignition problem.

Fuel pump should provide min. of 1 quart of fuel in 15 seconds, idling.

Should also check fuel tank and fuel line for resrictions, hose conditions, etc.

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post #5 of 7 (permalink) Old Apr 19th, 02, 05:43 PM
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If you're running breaker points, add a condensor to the list of oddities. Usually, a bad condensor will behave like a rev limiter regardless of load, but a cheap test non the less.

Make sure your secondaries aren't comming on too soon. Are they mechanical or vacuum operated?

-dnult
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post #6 of 7 (permalink) Old Apr 20th, 02, 01:31 PM
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The fuel pump should deliver a pint in 30-45 seconds.

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post #7 of 7 (permalink) Old Apr 21st, 02, 05:01 PM
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denverRS/SS, I am currently having the very same issue. Same exact symptoms, @ full throttle. I changed my fuel pump to a Holley Perf. mechanical and the same issue occurs, I changed fuel filter the same. My fuel pressure is @ 6lbs when the engine is cool and 3lbs when hot at idle and that is a concern I've had, but I think this is due to vapour lock.

What I have found that helped, is advancing the timing. The moment I did that, the bog at high RPMs went away and performance increased.



[This message has been edited by mikestr (edited 04-21-2002).]
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